U.S. Department of Labor
Occupational Safety & Health Administration
Federal Registers
Occupational Exposure to Tuberculosis; Proposed Rule - 62:54159-54309
• Publication Date: 10/17/1997
• Publication Type: Final Rules
• Fed Register #: 62:54159-54309
• Standard Number: 1910; 1904; 1926.62; 1960
• Title: Occupational Exposure to Tuberculosis; Proposed Rule
DEPARTMENT OF LABOR
Occupational Safety and Health Administration
29 CFR Part 1910
[Docket No. H-371]
RIN 1218-AB46
Occupational Exposure to Tuberculosis
AGENCY: Occupational Safety and Health Administration (OSHA), Labor
ACTION: Proposed rule and notice of public hearing.
SUMMARY: The Occupational Safety and Health Administration is proposing a health standard, to be promulgated under section 6(b) of the Occupational Safety and Health Act of 1970, 29 U.S.C. 655, to control occupational exposure to tuberculosis (TB). TB is a communicable, potentially lethal disease that afflicts the most vulnerable members of our society: the poor, the sick, the aged, and the homeless. As many as 13 million U.S. adults are presently believed to be infected with TB; over time, more than 1 million of these individuals may develop active TB disease and transmit the infection to others. TB remains a major health problem with 22,813 active cases reported in the U.S. in 1995. A number of outbreaks of this disease have occurred among workers in health care settings, as well as other work settings, in recent years. To add to the seriousness of the problem, some of these outbreaks have involved the transmission of multidrug-resistant strains of Mycobacterium tuberculosis, which are often fatal. Although it is the responsibility of the U.S. Public Health Service to address the problem of tuberculosis in the general U.S. population, OSHA is solely responsible for protecting the health of workers exposed to TB as a result of their job.
OSHA estimates that more than 5 million U.S. workers are exposed to TB in the course of their work: in hospitals, homeless shelters, nursing homes, and other work settings. Because active TB is endemic in many U.S. populations, including groups in both urban and rural areas, workers who come into contact with diseased individuals are at risk of contracting the disease themselves. The risk confronting these workers as a result of their contact with TB-infected individuals may be as high as 10 times the risk to the general population. Although the number of reported cases of active TB has slowly begun to decline after a resurgence between 1985-1992, 16 states reported an increase in the number of TB cases in 1995, compared with 1994. Based on a review of the data, OSHA has preliminarily concluded that workers in hospitals, nursing homes, hospices, correctional facilities, homeless shelters, and certain other work settings are at significant risk of incurring TB infection while caring for their patients and clients or performing certain procedures. To reduce this occupational risk, OSHA is proposing a standard that would require employers to protect TB-exposed employees by means of infection prevention and control measures that have been demonstrated to be highly effective in reducing or eliminating job related TB infections. These measures include the use of respirators when performing certain high hazard procedures on infectious individuals, procedures for the early identification and treatment of TB infection, isolation of individuals with infectious TB in rooms designed to protect those in the vicinity of the room from contact with the microorganisms causing TB, and medical follow-up for occupationally exposed workers who become infected. OSHA has preliminarily determined that the engineering, work practice, and administrative controls, respiratory protection, training, medical surveillance, and other provisions of the proposed standard are technologically and economically feasible for facilities in all affected industries.
DATES: Written comments on the proposed standard must be postmarked on or before December 16, 1997 and notices of intention to appear at the informal rulemaking hearings must be postmarked on or before December 16, 1997.
Parties requesting more than 10 minutes for their presentation at the hearings and parties submitting documentary evidence at the hearing must submit the full text of their testimony and all documentary evidence no later than December 31, 1997.
The informal public hearings will begin at 10:00 a.m. on the first day of hearing and at 9:00 a.m. on each succeeding day. The informal public hearings will be held in Washington, D.C. and are scheduled to begin on February 3, 1998.
ADDRESSES: Hearings will be held in the Auditorium of the U.S. Department of Labor (Frances Perkins Building), 200 Constitution Avenue, NW, Washington, D.C. Subsequent additional informal public hearings will be held in other U.S. locations. A Federal Register notice will be issued upon determination of the locations and dates of these hearings.
Comments on the proposed standard, Notices of Intention to Appear at the informal public hearings, testimony, and documentary evidence are to be submitted in quadruplicate to the Docket Officer, Docket No. H-371, Room N-2625, U.S. Department of Labor, 200 Constitution Ave., NW, Washington, DC 20210, telephone (202) 219-7894. Comments of 10 pages or fewer may be transmitted by fax to (202) 219-5046, provided the original and three copies are sent to the Docket Officer thereafter. The hours of operation of the Docket Office are 10:00 a.m. until 4:00 p.m.
Written comments, Notices of Intention to Appear at the informal rulemaking hearings, testimony, documentary evidence for the hearings, and all other material related to the development of this proposed standard will be available for inspection and copying in the Docket Office, Room N-2625, at the above address.
FOR FURTHER INFORMATION CONTACT: Bonnie Friedman, Office of Information and Consumer Affairs, Occupational Safety and Health Administration, Room N-3647, U.S. Department of Labor, 200 Constitution Ave., NW, Washington, DC 20210, Telephone (202) 219-8148, FAX (202) 219-5986.
SUPPLEMENTARY INFORMATION:
Table of Contents
| I. | Introduction |
| II. | Pertinent Legal Authority |
| III. | Events Leading to the Proposed Standard |
| IV. | Health Effects |
| V. | Preliminary Risk Assessment |
| VI. | Significance of Risk |
| VII. | Preliminary Economic and Regulatory Flexibility Analysis |
| VIII. | Unfunded Mandates |
| IX. | Environmental Impact |
| X. | Summary and Explanation of the Proposed Standard |
| XI. | Public Participation -- Notice of Hearing |
| XII. | Authority and Signature |
| XIII. | The Proposed Standard |
References to the rulemaking record are in the text of the preamble. References are given as "Ex." followed by a number to designate the reference in the docket. For example, "Ex. 1" means exhibit 1 in the Docket H-371. This document is a copy of the petition for a permanent standard filed by the Labor Coalition to Fight TB in the Workplace on August 25, 1993. A list of the exhibits and copies of the exhibits are available in the OSHA Docket Office.
I. Introduction
The preamble to the Proposed Standard for Occupational Exposure to Tuberculosis discusses the events leading to the development of the proposed standard, the health effects of exposure to tuberculosis, and the degree and significance of the risk. An analysis of the technological and economic feasibility of the proposal and an explanation of the rationale supporting the specific provisions of the proposed standard are also included.
Public comment on all matters discussed in this notice and all other relevant issues is requested for the purpose of assisting OSHA in the development of a new standard for occupational exposure to tuberculosis.
A. Issues
OSHA requests comment on all relevant issues discussed in this preamble, including the health effects, risk assessment, significance of risk determination, technological and economic feasibility and requirements that should be included in the final standard. OSHA is especially interested in responses, supported by evidence and reasons, to the following questions. This list is provided to assist persons in formulating comments, but is not intended to be all inclusive or to indicate that participants need to respond to all issues or follow this format. Please give reasons for your answers and provide data when available.
Specific issues of concern to OSHA are the following:
Health Effects
1. What, if any, additional studies or case reports on TB should be included in the health effects analysis?
2. Is there information that will provide data for estimating the rise in Multidrug-resistant TB (MDR-TB)? Is the rise in MDR-TB a serious threat?
Risk Assessment
1. Are there alternative risk assessment methodologies available? What are they? Are there other studies available that would be useful for assessing risk?
2. Are there factors other than or in addition to the ones OSHA has chosen that would be useful in estimating the background risk for TB?
Technological and Economic Feasibility
1. Are OSHA's estimates of the numbers and types of workers currently exposed to M. tuberculosis reasonable? If not, please provide estimates of the number of workers currently at risk and the percentage of the total workforce these workers represent, by industry.
2. Are OSHA's estimates of controlled access rates (i.e., the percentage of workers currently at risk who would remain at risk after employers minimize the number of workers exposed to individuals with suspected or confirmed infectious TB) reasonable? If the number of workers exposed to individuals with suspected or confirmed infectious TB is minimized, by what percentage could the number of workers at risk be reduced in each affected industry? In each industry, what are the job categories that would continue to be occupationally exposed?
3. Are OSHA's estimates of the numbers of affected establishments reasonable? If not, please provide estimates of the number of affected establishments, by industry.
4. Are OSHA's estimates of occupational and job turnover rates reasonable? If not, please provide estimates of turnover rates for each of the affected industries.
5. Under what conditions would social work, social welfare services, teaching, law enforcement or legal services need to be provided to individuals identified as having suspected or confirmed infectious TB? What, if any, procedures could not be postponed until such individuals are determined to be noninfectious? How many workers in each of these categories may need to have contact with individuals with suspected or confirmed infectious TB under these conditions?
6. Using the proposed definition of "suspected infectious TB," how many individuals with suspected infectious TB are likely to be encountered for every confirmed infectious TB case in each of the covered industries?
7. Are OSHA's estimates of the average number of suspected or confirmed infectious TB cases that would be transferred, per establishment in each industry, reasonable? If not, on average, how many TB cases per facility in each of the affected industries would be transferred?
8. How are individuals with suspected infectious TB transferred to establishments with AFB isolation facilities? Who pays for the transport of such cases, particularly for individuals transferred from homeless shelters? OSHA solicits comment on the feasibility of temporary AFB isolation facilities in homeless shelters and on methods that could be used to temporarily isolate individuals with suspected or confirmed infectious TB in homeless shelters.
9. Of the suspected infectious TB cases referred to hospitals from other facilities, how many are immediately ruled out without needing to be isolated?
10. Are OSHA's estimates of the number of necessary AFB isolation rooms reasonable? Are existing AFB isolation rooms reasonably accessible to facilities that transfer individuals with suspected or confirmed infectious TB?
11. What types of respirators are currently being used to protect workers against occupational exposure to M. tuberculosis?
12. Which of the NIOSH-approved N95 respirators meet all of the proposed criteria, including fit testing and fit checking criteria?
13. Are OSHA's estimates of respirator usage rates reasonable? For each of the covered industries, how often could respirators meeting the proposed requirements be reused and still maintain proper working condition? How often, on average, would respirators need to be replaced? Please specify the type of respirator.
14. OSHA has assumed, in its Preliminary Economic Analysis, that hospitals will have licensed health care professionals on-site to perform the medical procedures that would be required by the proposed rule, and that in the other industries, employees will have to travel off-site to receive the medical procedures. Which of the other affected industries typically have licensed health care professionals on site who could perform the required medical procedures? If employers were allowed two weeks to provide the medical procedures, rather than being required to provide them prior to initial assignment to jobs with occupational exposure, will it be less likely that employees will have to travel off site to receive these tests/procedures? What would the costs be if employees travel off-site for these tests/procedures?
15. Are OSHA's estimates of baseline compliance reasonable? If not, what types of controls are currently in place to protect workers against occupational exposure to M. tuberculosis, and what proportion of facilities in each of the affected industries currently are using such controls?
16. For facilities that have implemented controls to protect workers against occupational exposure to M. tuberculosis, how effective have such controls been in reducing the transmission of TB?
17. OSHA's Initial Regulatory Flexibility Analysis assesses the impacts of the proposed standard on small entities using the Small Business Administration's (SBA) size standards.
In addition, OSHA analyzed the impacts of the proposed standard on entities employing fewer than 20 workers. Are these definitions appropriate for the covered industries? If not, how should small entities be defined for each industry?
18. The SBA defines small government jurisdictions as "governments of cities, counties, towns, townships, villages, school districts, or special districts with populations of less than 50,000." OSHA requests comment on the number of such small government jurisdictions.
19. Some parties have suggested that OSHA should allow the use of the CDC guidelines as an alternative to the proposed rule. However, OSHA believes that the CDC guidelines are not written in a regulatory format that would allow OSHA's Compliance Safety and Health Officers (CSHOs) to determine whether or not an employer is in compliance with the Guidelines. Others have suggested that OSHA could judge compliance with the guidelines by determining the number or rate of skin test conversions at the employer's facility. OSHA does not believe that smaller facilities have an adequate population for trends in test conversions to have any statistical validity. OSHA welcomes suggestions on any methods of making the CDC guidelines an enforceable alternative to an OSHA regulation or methods of measuring performance that could be applied across all types and sizes of facilities.
20. Because of the limited availability of data, OSHA characterized the risk in many sectors as similar to that in hospitals, and less than that documented in nursing homes and home health care. OSHA welcomes industry-specific data on test conversion rates or active case rates.
21. OSHA is unable to determine the effectiveness of specific elements of an effective infection control program in hospitals. OSHA welcomes any evidence on the relative effectiveness of individual elements in such programs, such as the identification and isolation of suspect cases, the use of engineering controls, the use of respirators, and employee training.
22. OSHA based its estimate of the effectiveness of infection control programs in other sectors on studies of the effectiveness of such programs in hospitals. OSHA welcomes any data concerning the effectiveness of OSHA's proposed infection prevention measures, or of other alternative infection control measures, in sectors other than hospitals.
23. SBREFA Panel members suggested a number of alternative approaches to the regulation. OSHA believes that it has at least partially adopted a number of these approaches. OSHA welcomes comments and suggestions on these approaches and the extent to which OSHA should further adopt them:
24. OSHA is proposing to include homeless shelters in the Scope of the standard. During the informal public hearings, OSHA intends to schedule a special session for participants to present additional information on homeless shelters. Also, OSHA is conducting a special study of the homeless shelter sector. The information gathered in the study will be placed in the docket for public comment. OSHA welcomes comment on any of the topics this study will cover including:
-- Methods of isolation; and
-- How suspected TB cases are handled.
-- Costs of running a shelter;
-- Revenue sources;
-- How costs are accommodated as the number of homeless persons
served increases; and
-- Opportunities for cost pass-through;
-- Economic impacts in such states of covering volunteers (e.g., how costs would be handled, cost pass-through);
and
-- Protections currently offered to volunteers.
25. In what states, if any, do employers provide volunteers in the sectors affected by this proposed standard with the same protections as they provide to employees? How many volunteers might be affected by such requirements?
26. OSHA is concerned that medical removal protection and medical treatment of active cases of TB may have significant economic impacts on small firms that have an employee with an active case of TB. Is there any form of insurance available for covering the costs of medical removal protection or medical treatments required by the OSHA standard? Should OSHA consider phasing-in these provisions of the standard?
27. OSHA believes that substance abuse treatment centers, particularly in-patient treatment centers, normally have entry procedures that may include medical examinations. OSHA solicits comments on entry procedures for substance abuse treatment programs, the extent to which these entry procedures now include medical examinations, and the extent to which these examinations now include and examination for TB symptoms.
28. OSHA requests comment on the effects of extended compliance phase-in dates for the proposed requirements,particularly for respirators, for small businesses and facilities relying on charitable and/or Medicare and Medicaid funding.
29. OSHA requests comment on all assumptions and estimates used in developing the Preliminary Economic Analysis. Please provide reasons and data to support suggested changes to the assumptions and estimates.
30. The World Health Organization (WHO) has launched an initiative to reduce active TB through the use of multi-drug therapy and using directly observed therapy. OSHA solicits comment on whether it should revise its risk assessment or any of its benefits estimates as a result of this initiative.
31. OSHA requests comment on the number of affected facilities that are tribally-operated, by industry.
General
1. A number of provisions in the proposed standard are triggered by the identification of an individual as having either "suspected infectious tuberculosis" or "confirmed infectious tuberculosis." Of these provisions, are there some that should be triggered only once an individual has been identified as having "confirmed infectious tuberculosis?" If so, which provisions and why?
2. A number of the proposed standard's provisions require compliance or performance on an annual basis, e.g., reviews of the exposure control plan, the biosafety manual for laboratories, and the respiratory protection program; certification of biological safety cabinets; fit testing or a determination of the need for fit testing of respirators; medical histories, TB skin tests; and training. In addition, certain requirements must be performed on a semi-annual basis, e.g., inspection and performance monitoring of engineering controls, verification of air flow direction in laboratories, and, in some instances, TB skin testing. How can OSHA reduce the aggregate burden of these requirements, particularly in small entities, while still providing equal protection to employees? Of these annual and semi-annual provisions, which, if any, should be performed less frequently? Why and at what frequency? Which of these provisions, if any, should be performed more frequently? Why and at what frequency?
Scope
1. Is there information demonstrating risk of TB transmission for employees in work settings other than those included in the scope? Should OSHA, for example, expand the scope of this standard to cover all or some offices of general practitioners or dentists and if so, how? Should OSHA expand the scope to cover all teachers?
2. Are there provisions of the standard with which emergency medical services, home health care, and home-based hospice care employers cannot comply because their employees are at temporary work settings over which the employer has little or no control? If so, what are those provisions and why would an employer be unable to comply with them?
3. In covering only long-term care facilities for the elderly, is OSHA excluding similar facilities where there is increased risk of transmission of TB? If so, what are these facilities? Should OSHA include long-term care populations in addition to the elderly, such as long-term psychiatric care facilities? If so, what are these populations?
4. OSHA is proposing that employers provide medical management and follow-up for their employees who work in covered work settings, but who are not occupationally exposed, when they have an exposure incident resulting from an engineering control failure or similar workplace exposure. Is this the best way of assuring such employees receive medical management and follow-up?
5. OSHA is covering employees who have occupational exposure in covered work settings yet are not employees of the work setting (e.g., physician employed by another employer with hospital privileges, who is caring for a TB patient in the hospital). Can this be made more clear?
6. OSHA has proposed that facilities offering treatment for drug abuse be covered in the scope of the standard. Is coverage of such facilities appropriate? What factors unique to facilities that offer treatment for drug abuse would make compliance with the provisions of this proposed standard infeasible (e.g., would complying with certain provisions of the standard compromise the provision of services at facilities that offer treatment for drug abuse)?
Application
1. OSHA has proposed that an employer covered under the standard (other than an operator of a laboratory) may claim reduced responsibilities if he or she can demonstrate that his or her facility or work setting: (1) Does not admit or provide medical services to individuals with suspected or confirmed infectious TB; (2) has had no case of confirmed infectious TB in the past 12 months; and (3) is located in a county that, in the past 2 years, has had 0 cases of confirmed infectious TB reported in one year and fewer than 6 cases of confirmed infectious TB reported in the other year. Are there alternative methods that can be used to assure protection of employees in areas where infectious TB has not recently been encountered?
Exposure Control Plan
1. OSHA has proposed that the employer's exposure control plan contain certain policies and procedures. What, if any, policies and procedures should be added to the plan?
2. The proposed standard requires exposure incidents and skin conversions to be investigated, but does not require aggregate data regarding employee conversions to be collected and analyzed. Would the collection and analysis of aggregate data provide benefits beyond those provided by investigating each individual exposure incident or conversion? Why or why not? If aggregate data collection and analysis were required, what type of analysis should be required, at what analytical endpoint should employer action be required, and what should that action be?
3. OSHA has set forth the extent of responsibility for transfer of individuals based upon the type of work setting where such individuals are encountered. What are current practices regarding transfer of individuals with suspected or confirmed infectious TB in the work settings covered by the proposal?
Work Practices and Engineering Controls
1. Is OSHA's time limit of 5 hours following identification for transferring an individual with suspected or confirmed infectious TB to another facility or placing the individual into AFB isolation appropriate? If not, what is the maximum amount of time that an individual should be permitted to await transfer or isolation in a facility before the employer must implement the other provisions of the proposed standard?
2. OSHA has considered requiring facilities that encounter 6 or more individuals with confirmed infectious TB within the past 12 months to provide engineering controls in intake areas where early identification procedures are performed (e.g., emergency departments, admitting areas). Should this be a requirement? Are there types of controls, engineering or otherwise, that would be effective in controlling transmission in intake areas? Would the trigger of 6 individuals with confirmed infectious TB be appropriate?
3. Are there methods other than smoke trail testing and continuous monitors that would be effective for verifying negative pressure in AFB isolation rooms or areas?
4. OSHA is requiring engineering controls to be inspected and performance monitored every 6 months. Is this frequency appropriate?
5. OSHA is allowing exhaust air from AFB isolation rooms or areas where M. tuberculosis may be aerosolized that cannot feasibly be discharged directly outside to be HEPA-filtered and recirculated back into general ventilation. Is permitting such recirculation appropriate? If used, should there be any requirements to detect system failure?
6. OSHA is permitting stand-alone HEPA filter units to be used as a primary control measure. Is this appropriate? What, if any, methods other than ventilation and filtration can provide consistent protection?
7. Should ambulances that have carried an individual with suspected or confirmed infectious TB be required to be ventilated for a specific period of time or in a particular way before allowing employees to enter without a respirator? What engineering controls are available for ambulances?
Laboratories
1. The standard does not require labeling of laboratory specimens. Should OSHA require that laboratory specimens be labeled within the facility or when specimens are being shipped? If so, what should the label contain? Are there other agencies that require these specimens be labeled? What are these agencies and what is required?
2. OSHA has attempted to incorporate the CDC/NIH recommendations given in "Biosafety in Microbiological and Biomedical Laboratories" into the standard. Do any provisions need to be added in order for employees in clinical and research laboratories to be fully protected against exposures to M. tuberculosis?
Respirators
1. OSHA is requiring employees who are transporting an unmasked individual with suspected or confirmed infectious TB within a facility to wear a respirator. Is this appropriate? How often would an individual with suspected or confirmed infectious TB be transported unmasked through a facility? Under what circumstances would it be infeasible to mask such an individual? What other precautions should be taken when transporting such an individual who is not masked?
2. OSHA is requiring that maintenance personnel use respiratory protection during maintenance of air systems or equipment that may reasonably be anticipated to contain aerosolized M. tuberculosis. When would it be necessary to access such an air system at the time it was carrying air that may contain aerosolized M. tuberculosis? Should OSHA require that such air systems be purged and shut down whenever these systems are accessed for maintenance or other procedures?
3. OSHA has received information that the use of certain kinds of respirators in helicopters providing emergency medical services may hamper pilot communication. Have other air ambulance services encountered this problem? Does this problem exist when the employee is using a type N95 respirator or other types of respiratory protection such as powered air purifying respirators? What other infection control or industrial hygiene practices could be implemented to minimize employee exposure in these circumstances?
4. The CDC states that there may be selected settings and circumstances (e.g., bronchoscopy on an individual with suspected or confirmed infectious TB or an autopsy on a deceased individual suspected of having had active TB at the time of death) where the risk of transmission may be such that increased respiratory protection such as that provided by a more protective negative-pressure respirator or a powered air purifying respirator may be necessary. Are there circumstances where OSHA should require use of a respirator that is more protective than a type N95 respirator? If so, what are the circumstances and what type of respiratory protection should be required?
5. OSHA is proposing that respirators be fit-tested annually, which is consistent with general industrial hygiene practice, or, in lieu of an annual fit test, that employees have their need to receive the annual fit test be evaluated by the physician or other licensed health care professional, as appropriate. For the circumstances and conditions regulated by this standard, will the evaluation provide enough ongoing information about the fit of a respirator to be an adequate substitute for fit testing? Should OSHA require that an actual fit test be performed periodically? If so, at what frequency?
6. OSHA has not included any provisions regarding the use of supplied air respirators. Are there circumstances in which supplied air respirators would be used to protect against M. tuberculosis? Should OSHA include provisions addressing supplied air respirators in the standard?
7. OSHA is permitting the reuse of disposable respirators provided the respirator does not exhibit excessive resistance, physical damage, or any other condition that renders it unsuitable for use. Will the respirators continue to protect employees throughout the reuse period?
8. In the proposed standard for TB, OSHA has included separate provisions for all aspects of a respiratory protection program for tuberculosis. What other elements might need to be included? Which respiratory protection provisions, if any, are not appropriate for protection against TB? Please provide reasons and data to support inclusion or exclusion of particular provisions.
Medical Surveillance
1. Should any provisions be added to the Medical Surveillance program?
2. OSHA has not required that physical exams be included as part of the baseline evaluation. Is there information that is essential to medical surveillance for TB that can only be learned from a baseline physical exam?
3. OSHA is specifying tuberculin skin testing frequencies for employees with negative skin tests. Should tuberculin skin testing be administered more or less frequently? Are there other ways to determine the frequency of tuberculin skin testing?
4. OSHA is proposing that employees entering AFB isolation rooms or areas be skin tested every 6 months. However, employees providing home health care, home care, and home-based hospice care are to be skin tested annually. Employees entering the home of an individual who has suspected or confirmed infectious TB may have the same potential for exposure to aerosolized M. tuberculosis as employees who enter an isolation room. In light of this, should employees providing care to individuals with suspected or confirmed infectious TB in private homes be skin tested every 6 months?
5. OSHA is requiring that all tuberculin skin testing be administered, read, and interpreted by or under the supervision of a physician or other licensed health care professional, as appropriate, according to current CDC recommendations. Should OSHA require specific training for individuals who are administering, reading, and interpreting tuberculin skin tests? If so, what type of training should be required?
6. Should OSHA require a declination form for employees who do not wish to undergo tuberculin skin testing?
7. OSHA is including Medical Removal Protection (MRP) provisions for employees who are unable to wear respiratory protection or who contract infectious tuberculosis. Are there additional provisions that need to be included? What remedies are available to employees in states where worker compensation system do not consider occupational TB a compensable disease? What benefits are provided to workers who are unable to wear a respirator?
8. OSHA is requiring that employees who must wear a respirator be provided a face-to-face determination of their ability to wear the respirator. Does this determination need to be made through a medical evaluation or would the use of an appropriately designed questionnaire be adequate? What would be the advantages and disadvantages of relying on a questionnaire to make this determination? Are there sample questionnaires that have proven to be effective for determining an employee's ability to wear a respirator?
9. OSHA has drafted Medical Surveillance, paragraph (g), to explain first who must be provided with the protections listed in the paragraph and how the surveillance is to be administered and secondly, in paragraphs (g)(2), Explanation of Terms, and (g)(3), Application, how the general medical terms are to be construed to meet the standard and in what instances the medical examinations or tests are to be offered. The Agency realizes that there is some repetition in these paragraphs and seeks comment on whether there might be a better way to list the requirements.
Communication of Hazards and Training
1. OSHA is requiring that signs for isolation rooms and areas bear a "STOP" Sign and the legend "No Admittance Without Wearing A Type N95 or More Protective Respirator." Is there another sign that would assure patient confidentiality while providing adequate notification of the hazard and the necessary steps to minimize the hazard for employees who may be inadvertently exposed?
2. OSHA is requiring that ducts be labeled "Contaminated Air -- Respiratory Protection Required." Should OSHA require that duct labels also include the "STOP" sign?
3. Is the labeling of ducts carrying air that may contain aerosolized M. tuberculosis (e.g., from isolation rooms and areas, labs) at all access points feasible? What, if any, equally protective alternative exists to permanent labeling in situations where an exhaust duct from a room may or may not be carrying air containing aerosolized M. tuberculosis (e.g., the exhaust duct would only be carrying aerosolized M. tuberculosis when an individual with infectious TB is being isolated in the room)?
Dates
1. OSHA has proposed that very small businesses with fewer than 20 employees be given an additional 3 months to comply with the standard's engineering control provisions (i.e., the start-up date for engineering controls for small businesses would be 270 days from the Effective Date of the standard). Are there other requirements of the proposed standard (e.g., respiratory protection) for which very small businesses should be given additional time to come into compliance? If so, for which provisions would they need additional time and why? Are 20 employees an appropriate cut-off for this purpose? Are there other employers that may need extended time to achieve compliance?
Definitions
1. A number of provisions in the standard are triggered by the identification of an individual as having "suspected infectious tuberculosis." Under the definition of "suspected infectious tuberculosis", OSHA has proposed criteria that the Agency believes are the minimum indicators that, when satisfied by an individual, require an employer to consider that the individual may have infectious tuberculosis. Are there other criteria that should be included in this definition?
2. Coverage of an employee under the standard is based upon the definition of "occupational exposure." Similar to OSHA's Bloodborne Pathogens standard, occupational exposure is dependent upon reasonable anticipation of contact with an individual with suspected or confirmed infectious tuberculosis or with air that may contain aerosolized M. tuberculosis. Are there additions that could be made to this definition that would help employers determine which of their employees are occupationally exposed?
3. OSHA has proposed requirements for research laboratories that differ from those of clinical laboratories. The standard includes definitions of "research laboratory" and "clinical laboratory" to assist the employer in differentiating between these two types of laboratory. Do the definitions clearly differentiate between these two types of laboratories? Should such a distinction be made? Are there any modifications that should be made to these definitions?
B. Information Collection Requirements
This proposed Tuberculosis standard contains collections of information that are subject to review by the Office of Management and Budget (OMB) under the Paperwork Reduction Act of 1995 (PRA'95), 44 U.S.C. 3501 et seq. and the regulation at 5 CFR § 1320. PRA'95 defines collection of information to mean, "the obtaining, causing to be obtained, soliciting, or requiring the disclosure to third parties or the public of facts or opinions by or for an agency regardless of form or format." [44 U.S.C. § 3502(3)(A)].
The title, description of the need for and proposed use of the information, summary of the collections of information, description of the respondents, and frequency of response of the information collection are described below with an estimate of the annual cost and reporting burden, as required by 5 CFR § 1320.5(a)(1)(iv) and § 1320.8(d)(2). Included in the estimate is the time for reviewing instructions, gathering and maintaining the data needed, and completing and reviewing the collection of information.
OSHA invites comments on whether the proposed collection of information:
(1) Ensures that the collection of information is necessary for the proper performance of the functions of the agency, including whether the information will have practical utility;
(2) Estimates the projected burden accurately, including whether the methodology and assumptions used are valid;
(3) Enhances the quality, utility, and clarity of the information to be collected; and
(4) Minimizes the burden of the collection of information on those who are to respond, including through the use of appropriate automated, electronic, mechanical, or other technological collection techniques or other forms of information technology, e.g., permitting electronic submissions of responses.
Title: Tuberculosis 29 CFR 1910.1035.
Description: The proposed Tuberculosis (TB) Standard is an occupational safety and health standard that will prevent or minimize occupational exposure to TB. The standard's information collection requirements are essential components that will protect employees from occupational exposure. The information will be used by employers and employees to implement the protection required by the standard. OSHA compliance officers will use some of the information in their enforcement of the standard.
Respondents: The respondents are employers whose employees may have occupational exposure in the following settings: hospitals; long-term care facilities for the elderly; correctional facilities and other facilities that house inmates or detainees; hospices; shelters for the homeless; facilities that offer treatment for drug abuse; facilities where high hazard procedures are performed; and laboratories that handle specimens that may contain M. tuberculosis or process or maintain the resulting cultures, or perform related activity that may result in the aerosolization of M. tuberculosis.
Also, occupational exposure occurring during the provision of social work, social welfare services, teaching, law enforcement or legal services would be covered if the services are provided in the work settings previously mentioned, or in residences, to individuals who are in AFB isolation or are segregated or otherwise confined due to having suspected or confirmed infectious TB. Respondents also include employers whose employees are occupationally exposed during the provision of emergency medical services, home health care and home-based hospice care. Approximately 101,875 employers will be responding to the standard.
Total Estimated Cost: First year $62,972,210; Recurring years $53,691,915.
The Agency has submitted a copy of the information collection request to OMB for its review and approval. Interested parties are requested to send comments regarding this information collection to the Office of Information and Regulatory Affairs, Attn. OSHA Desk Officer, OMB New Executive Office Building, 725 17th Street NW, Room 10235, Washington DC 20503.
Comments submitted in response to this notice will be summarized and/or included in the request for Office of Management and Budget approval of the final information collection request: they will also become a matter of public record.
Copies of the referenced information collection request are available for inspection and copying in the OSHA Docket Office and will be mailed immediately to any person who request copies by telephoning Todd Owen at (202) 219-7075. For electronic copies of the Tuberculosis information collection request, contact the Labor News Bulletin Board (202) 219-4784, or OSHA web page on the Internet at http://www.osha.gov/. Copies of the information collection requests are also available at the OMB docket office.
C. Federalism
This standard has been reviewed in accordance with Executive Order 12612, 52 FR 41685 (October 30, 1987), regarding Federalism. This Order requires that agencies, to the extent possible, refrain from limiting State policy options, consult with States prior to taking any actions that would restrict State policy options, and take such actions only when there is clear constitutional authority and the presence of a problem of national scope. The Order provides for preemption of State law only if there is a clear Congressional intent for the Agency to do so. Any such preemption is to be limited to the extent possible.
Throughout the development of this proposed standard, OSHA has sought and received assistance from state representatives. Representatives of state departments of health and labor and industries have helped direct OSHA to pertinent information and studies on TB and have submitted drafts of state standards relevant to TB. In addition, representatives of state occupational safety and health departments participated in the review of the draft standard by OSHA field offices and in OSHA's TB Stakeholder meetings, where the requirements of the proposed standard were presented and information was collected from employers, employees, and their representatives on what was being done to prevent occupational exposure to TB in the various worksites and how an OSHA standard for TB could further reduce the exposures.
Section 18 of the Occupational Safety and Health Act (OSH Act), expresses Congress' clear intent to preempt State laws with respect to which Federal OSHA has promulgated occupational safety or health standards. Under the OSH Act a State can avoid preemption only if it submits, and obtains Federal approval of, a plan for the development of such standards and their enforcement. Occupational safety and health standards developed by such State-Plan states must, among other things, be at least as effective in providing safe and healthful employment and places of employment as the Federal standards.
The proposed tuberculosis standard is drafted so that employees in every State will be protected by general, performance-oriented standards. To the extent that there are State or regional peculiarities, States with occupational safety and health plans approved under Section 18 of the OSH Act would be able to develop their own State standards to deal with any special problems. Moreover, the performance nature of this standard, of and by itself, allows for flexibility by States and employers to provide as much safety as possible using varying methods consonant with conditions in each State.
There is a clear national problem related to occupational safety and health for employees exposed to M. tuberculosis. Approximately 6.5 % of the U.S. adult population is infected (i.e., carrying the tuberculosis bacillus, not manifesting active disease), and although the prevalence of TB infection and disease varies throughout the country, TB disease has been reported in every state. Political and geographic boundaries do not contain infection and disease spread. The U.S. population is mobile, moving freely from place to place for business and pleasure. Immigrants, a group whose members are known to have a high prevalence of TB, settle throughout the country. While there are counties that do not report cases in a given year, the counties change from year to year along with the number of cases reported. In addition, reports do not always reflect all the locations where exposure incidents can occur; infectious TB cases are often transferred from their site of diagnosis to a distant location for treatment and reported as a TB case only in the county where treatment is administered. Finally, underreporting may occur because some individuals with infectious TB, in particular the homeless and clients of drug abuse facilities, do not avail themselves of further diagnosis and treatment. TB infection and disease is truly national in scope.
Those States which have elected to participate under Section 18 of the OSH Act would not be preempted by this regulation and would be able to deal with special, local conditions within the framework provided by this performance-oriented standard while ensuring that their standards are at least as effective as the Federal standard.
D. State Plans
The 23 States and 2 territories with their own OSHA-approved occupational safety and health plans must adopt a comparable standard within 6 months after the publication of a final standard for occupational exposure to tuberculosis or amend their existing standard if it is not "at least as effective" as the final Federal standard. OSHA anticipates that this standard will have a substantial impact on state and local employees. The states and territories with occupational safety and health state plans are: Alaska, Arizona, California, Connecticut, Hawaii, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Nevada, New Mexico, New York, North Carolina, Oregon, Puerto Rico, South Carolina, Tennessee, Utah, Vermont, Virginia, the Virgin Islands, Washington, and Wyoming. (In Connecticut and New York, the plan covers only State and local government employees). Until such time as a State standard is promulgated, Federal OSHA will provide interim enforcement assistance, as appropriate.
II. Pertinent Legal Authority
The purpose of the Occupational Safety and Health Act, 29 U.S.C. 651 et seq. ("the Act") is "to assure so far as possible every working man and woman in the nation safe and healthful working conditions and to preserve our human resources." 29 U.S.C. § 651(b). To achieve this goal Congress authorized the Secretary of Labor to promulgate and enforce occupational safety and health standards. 29 U.S.C. Secs. 655(a) (authorizing summary adoption of existing consensus and federal standards within two years of Act's enactment), 655(b) (authorizing promulgation of standards pursuant to notice and comment), 654(b) (requiring employers to comply with OSHA standards).
A safety or health standard is a standard "which requires conditions, or the adoption or use of one or more practices, means, methods, operations, or processes, reasonably necessary or appropriate to provide safe or healthful employment or places of employment." 29 U.S.C. § 652(8).
A standard is reasonably necessary or appropriate within the meaning of Section 652(8) if it substantially reduces or eliminates significant risk, and is economically feasible, technologically feasible, cost effective, consistent with prior Agency action or supported by a reasoned justification for departing from prior Agency actions, supported by substantial evidence, and is better able to effectuate the Act's purposes than any national consensus standard it supersedes. See 58 Fed. Reg. 16612 -- 16616 (March 30, 1993).
OSHA has generally considered, at a minimum, a fatality risk of 1/ 1000 over a 45-year working lifetime to be a significant health risk. See the Benzene standard, Industrial Union Dep't v. American Petroleum Institute, 448 U.S. 607, 646 (1980); the Asbestos standard, International Union, UAW v. Pendergrass, 878 F.2d 389, 393 (D.C. Cir. 1989).
A standard is technologically feasible if the protective measures it requires already exist, can be brought into existence with available technology, or can be created with technology that can reasonably be expected to be developed. American Textile Mfrs. Institute v. OSHA, 452 U.S. 490, 513 (1981) ("ATMI"), American Iron and Steel Institute v. OSHA, 939 F.2d 975, 980 (D.C. Cir. 1991)("AISI").
A standard is economically feasible if industry can absorb or pass on the costs of compliance without threatening its long-term profitability or competitive structure. See ATMI, 452 U.S. at 530 n. 55; AISI, 939 F.2d at 980.
A standard is cost effective if the protective measures it requires are the least costly of the available alternatives that achieve the same level of protection. ATMI, 453 U.S. at 514 n. 32; International Union, UAW v. OSHA, 37 F.3d 665, 668 (D.C. Cir. 1994) ("LOTO III").
All standards must be highly protective. See 58 FR 16614 -- 16615; LOTO III, 37 F.3d at 669. However, health standards must also meet the "feasibility mandate" of Section 6(b)(7) of the Act, 29 U.S.C. § 655(b)(5). Section 6(b)(5) requires OSHA to select "the most protective standard consistent with feasibility" that is needed to reduce significant risk when regulating health hazards. ATMI, 452 U.S. at 509.
Section 6(b)(5) also directs OSHA to base health standards on "the best available evidence," including research, demonstrations, and experiments. 29 U.S.C. § 655(b)(5). OSHA shall consider "in addition to the attainment of the highest degree of health and safety protection * * * the latest scientific data * * * feasibility and experience gained under this and other health and safety laws." Id.
Section 6(b)(7) authorizes OSHA to include among a standard's requirements labeling, monitoring, medical testing and other information gathering and transmittal provisions. 29 U.S.C. § 655(b)(7).
Finally, whenever practical, standards shall "be expressed in terms of objective criteria and of the performance desired." Id.
III. Events Leading to the Proposed Standard
Tuberculosis (TB) is a contagious disease caused by the bacterium Mycobacterium tuberculosis (M. tuberculosis). Infection is usually acquired by the inhalation of airborne particles carrying the bacterium. These airborne particles, called droplet nuclei, can be generated when persons with infectious pulmonary or laryngeal TB cough, sneeze, or speak. TB has long been considered an occupational hazard in the health care setting. However, it is inhalation exposure to aerosolized M. tuberculosis and not some other factor unique to the health care setting that places workers at risk of infection. Thus, any work setting where employees can reasonably be anticipated to encounter individuals with infectious TB also contains the occupational hazard of TB infection.
On December 21, 1992, the Labor Coalition to Fight TB in the Workplace (the Coalition) requested the Agency to issue nationwide enforcement guidelines to protect workers against exposure to TB in health care, criminal justice, and other high risk settings and to issue a Joint Advisory Notice on TB in conjunction with the Centers for Disease Control and Prevention (CDC) (Ex. 2). This petition was signed by the presidents of the Service Employees International Union (SEIU), the American Federation of State, County, and Municipal Employees (AFSCME), and the American Federation of Teachers (AFT), and was endorsed by 9 other unions. The petition included a list of provisions that the petitioners felt should be included in the guidelines, ranging from a written control plan and medical surveillance to anti-discrimination language and medical removal protection.
Eight months later, on August 25, 1993, the Coalition petitioned OSHA to initiate rulemaking for a permanent standard issued under § 655(b) of the Act to protect workers from occupational transmission of TB (Ex. 1). Citing the recent resurgence of TB and the emergence and increasing rate of new cases of multidrug-resistant TB (MDR-TB), the petitioners stressed the need for a substance-specific standard to address the hazards associated with occupational exposures to TB. The petitioners contended that the non-mandatory CDC TB Guidelines do not provide adequate protection because they are not fully or rigorously implemented in most workplaces. They also stated that in every outbreak of TB investigated by CDC, noncompliance with the Guidelines was evident.
In addition to a permanent standard, the petitioners also requested that OSHA immediately issue the nationwide enforcement guidelines that the Coalition had previously requested, and that OSHA promulgate an Emergency Temporary Standard (ETS) as an interim measure. The Coalition requested that the standard be applicable to all work settings where employees can reasonably anticipate contact with infectious TB. The petition included a discussion on occupational risk that included both the traditional high-risk occupations and other occupations such as sheet metal workers, postal workers, airline employees, teachers, and office workers.
Like the request for nationwide enforcement guidelines, the petition contained provisions that the petitioners requested be included in the standard. Examples include a facility hazard assessment and written exposure control plan, engineering and work practice controls, respiratory protection, medical surveillance (e.g., tuberculin skin testing) and counseling, post-exposure management, outbreak management, training, and recordkeeping.
On October 8, 1993, OSHA issued nationwide enforcement procedures for occupational exposure to TB. The compliance document contained the enforcement procedures that the Agency could and would use in certain work settings for protecting workers with occupational exposure to TB. In the compliance procedures, the Agency noted that although OSHA has no standard designed specifically to reduce occupational exposure to TB, the Agency has existing standards that apply to this hazard. For example, 29 CFR 1910.134 requires employers to provide respiratory protection equipment and 29 CFR 1910.145(f) requires accident prevention tags to warn of biological hazards. In addition, section 5(a)(1), the General Duty Clause of the Act, requires that each employer:
* * * furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.
On January 26, 1994, in response to their August 25 petition, Secretary of Labor Robert B. Reich informed the petitioners that OSHA was initiating rulemaking on a permanent standard to be issued under Section 6(b)(5) of the Act for occupational exposure to TB (Ex. 1B). At the same time, the petitioner's request for an ETS was denied. The Agency had determined that the available data did not meet the criteria for an ETS as set forth in Section 6(c) of the Act. However, OSHA committed to enforcing existing regulations and Section 5(a)(1) of the Act in certain work settings while preparing this standard.
On October 28, 1994 the CDC issued revised guidelines for preventing the transmission of tuberculosis in health care facilities (Ex. 4B). In addition, in June of 1995, the National Institute for Occupational Safety and Health (NIOSH) published revised certification procedures for non-powered air purifying particulate respirators (Ex. 7-261). As a result of changes in these two documents, OSHA issued revised enforcement policies and procedures relative to TB in February of 1996 (Ex. 7-260).
In October and November of 1995, OSHA held a series of meetings with stakeholder groups representing labor unions, professional organizations, trade associations, state and federal government, representatives of employers, as well as frontline workers from the various sectors anticipated to be covered by the proposed standard. During these meetings, participants provided input relative to the concepts and approaches OSHA was considering for the proposed tuberculosis standard.
In September of 1996, in accordance with the Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), a Small Business Advocacy Review Panel was convened to consider the impact of OSHA's draft proposed tuberculosis standard on affected small entities. The panel, comprised of members from the Office of Advocacy of the Small Business Administration (SBA), the Office of Management and Budget (OMB), and OSHA, prepared a report based on the Panel's findings and recommendations with regard to comments on the standard received from small business employers. This report was submitted to the Assistant Secretary for OSHA for its consideration during the development of the standard (Ex. 12). OSHA's proposed standard reflects input generated during both the stakeholder meetings and the SBREFA review process.
Comparison of OSHA's Proposed Standard and CDC's Revised Guidelines
In preparing its proposed standard for TB, OSHA has relied heavily on the expertise of CDC. The Agency has consulted with CDC and has incorporated the basic elements of CDC's revised guidelines for preventing the transmission of M. tuberculosis in health care facilities in this proposed standard. Both CDC and OSHA rely on minimizing exposures and consequent transmission by identifying suspected infectious TB individuals and isolating them. The OSHA proposed standard includes the following CDC components: written exposure control plans, procedures for early identification of individuals with suspected or confirmed infectious TB, procedures for initiating isolation of individuals with suspected or confirmed infectious TB or for referring those individuals to facilities with appropriate isolation capabilities, procedures for investigating employee skin test conversions, and education and training for employees. In addition, OSHA has incorporated CDC recommendations for engineering control measures such as the use of negative pressure for AFB isolation rooms or areas, daily monitoring of negative pressure while AFB isolation rooms are in use for TB, HEPA filtration of recirculated air from AFB isolation rooms, and periodic maintenance and monitoring of engineering controls. With regard to respiratory protection, OSHA has adopted CDC's standard performance criteria for the selection of respiratory protection devices appropriate for use against M. tuberculosis. And finally, where appropriate, OSHA has attempted to assure that where certain practices are required by OSHA's proposed standard, e.g., tuberculin skin testing and medical management and follow-up of employees who acquire TB infections or active disease, these practices are conducted according to the current recommendations of the CDC. Therefore, OSHA's proposed standard for occupational exposure to TB closely follows CDC's recommended elements for a TB infection control program.
However, there are some minor differences between OSHA's proposed standard and CDC's guidelines that gobeyond the obvious enforcement distinction between a guideline and a standard. These differences are found primarily in the areas of risk assessment, medical surveillance and respiratory protection. Even so, OSHA believes that despite these differences the vast majority of the provisions included in this proposed standard closely track the recommendations of the CDC. The following discussion identifies where these differences occur and describes the extent of these differences and the degree to which they impact on employers' responsibilities under the proposed standard.
Risk Assessment
As a part of its guidelines, CDC recommends that a risk assessment be conducted in all facilities to assess the risk of transmission of M. tuberculosis in each facility. This risk assessment is to be conducted using information such as the profile of TB in the community, the number of suspected and confirmed cases of TB among patients and health care workers, results of health care worker tuberculin skin testing (i.e., conversion rates), and observation of TB infection control practices. Using the results of this risk assessment, appropriate infection control interventions can then be selected based on the actual risk in the facility. CDC includes a protocol for conducting this risk assessment in which there are 5 categories of risk: "minimal", "very-low", "low", "intermediate", and "high". Each category from "minimal" to "high" has an increasing number of infection control interventions that are recommended for each particular level of risk.
OSHA, however, has chosen a simpler approach and is not requiring employers to conduct such a risk assessment. Consistent with other standards, OSHA has determined that employees in the work settings and employees providing services set forth in the scope section are at risk of occupational exposure to TB. Their employers are required to conduct an exposure assessment to determine which employees have occupational exposure, i.e., reasonably anticipated contact with an individual with suspected or confirmed infectious TB or air that may contain aerosolized M. tuberculosis. The standard then specifies the provisions applicable for the employees whom the employer has identified as having occupational exposure. In addition, consistent with its approach in other standards, OSHA does not require that individual risk assessments be conducted by each work setting covered under the standard, as they may be too difficult and burdensome for employers to prepare. Also, many work settings will have too few occupationally exposed employees to do an accurate risk assessment. Finally, conducting the risk assessments in order to determine applicable duties may require a level of expertise some facilities lack, making enforcement burdensome for the Agency.
OSHA realizes, however, that in many work settings, very few individuals with suspected or confirmed infectious TB may be seen and that in many of those work settings, individuals with suspected or confirmed infectious TB will be transferred to other facilities that are better equipped to provide services and care using appropriate TB isolation precautions. Because there is likely to be less risk of transmission of M. tuberculosis in those situations, OSHA believes that it is possible to make the standard less burdensome for the employers with these types of work settings while still maintaining worker protection.
For example, an employer who can demonstrate that his or her facility or work setting: (1) Does not admit or provide medical services to individuals stwith suspected or confirmed infectious TB, (2) has not had any individuals with confirmed infectious TB within the work setting within the last 12 months, and (3) is located in a county that, in the past 2 years, has had 0 cases of confirmed infectious TB reported in one year and fewer than 6 cases of confirmed infectious TB reported in the other year, does not have to comply with all provisions of the standard. Such employers would only be responsible for compliance with certain provisions, e.g., a written exposure control plan, a baseline skin test and medical history, medical management and follow-up after exposure incidents, medical removal protection where necessary, employee training, and recordkeeping. These provisions are very similar to the recommendations of the CDC for facilities classified as having "minimal risk," i.e., no TB in the community or in the facility. The only major difference is that CDC does not recommend baseline skin testing. However, CDC does state that baseline skin testing would be advisable so that if an unexpected exposure does occur, conversion could be distinguished from positive skin test results caused by previous exposures.
Medical Surveillance
In the area of medical surveillance, the main differences between OSHA and CDC are related to tuberculin skin testing. OSHA requires baseline skin testing for all employees whom the employer identifies as having occupational exposure. CDC recommends baseline skin testing for all employees with potential exposure except those who work in facilities that fall into CDC's "minimal risk" category. However, CDC notes that even for employees in "minimal risk" facilities, it may be advisable to perform baseline skin testing so that if unexpected exposures do occur, conversions can be distinguished from positive skin test results caused by previous exposures. Thus, there is little difference between OSHA requirements and CDC recommendations with regard to baseline skin testing.
Relative to periodic skin testing, OSHA requires periodic re-testing for all employees identified as having occupational exposure who have negative skin tests except for the employees of those employers who have no TB in the community and who have not encountered any individuals with confirmed infectious TB in their work settings within the past year. CDC recommends re-testing for employees in the "low", "intermediate", and "high" risk categories. According to the CDC guidelines, periodic re-testing is not necessary for employees in the "minimal" risk category or the "very-low" risk categories. CDC's periodic skin test recommendations for the "minimal" risk category are similar to OSHA's limited program for employers who do not admit or provide medical services to individuals with suspected or confirmed infectious TB, have not encountered any confirmed infectious TB in their work setting, and are located in a county that, in the past 2 years, has reported 0 cases of confirmed infectious TB in one year and fewer than 6 cases in the other year. OSHA is different from the CDC in that employees in a "very-low risk category" are required to be periodically retested. However, CDC notes that even in the "very-low" risk category, employees who are involved in the initial assessment of individuals in emergency departments and admitting areas may have potential exposure and thus may need periodic re-testing.
Another difference between CDC and OSHA is the frequency of the re-testing. This is primarily due to the fact that OSHA's required frequencies are based on the type of work that employees do that result in exposures whereas CDC's recommendations are based more on evidence of conversions. For example, OSHA requires re-testing every six months for all employees who (1) enter AFB isolation rooms or areas, (2) perform high-hazard procedures, (3) transport individuals with suspected or confirmed infectious TB in an enclosed vehicle, or (4) work in intake areas where early identification procedures are performed (e.g., emergency departments, admitting areas) in facilities where 6 or more individuals with confirmed infectious TB have been encountered in the past 12 months. For all other employees with occupational exposure, re-testing is required every 12 months. In comparison, CDC recommends re-testing every year for employees in "low" risk categories, every 6-12 months for employees in "intermediate" risk categories, and every 3 months for employees in "high" risk categories. Under CDC recommendations, employees in "low" risk categories who enter AFB isolation rooms or areas or employees who transport individuals with suspected or confirmed infectious TB in an enclosed vehicle would be re-tested every 12 months. However, under OSHA requirements, those same employees would be required to be re-tested every six months. Thus, OSHA is more protective than CDC in this case.
OSHA also would require that employees who perform high-hazard procedures or who work in intake areas where early identification procedures are performed in facilities that encounter 6 or more individuals with confirmed infectious TB be re-tested every six months. Under CDC's Guidelines employees in areas in which cough-inducing procedures are performed on individuals who may have active TB are recommended to follow an intermediate risk protocol. Similarly, CDC recommends that an intermediate risk protocol be followed in areas where more than six individuals who may have active TB receive initial assessment and diagnostic evaluation (e.g., ambulatory care, emergency departments, admitting areas). CDC recommends re-testing every 6-12 months for employees in intermediate risk categories. OSHA would require re-testing every 6 months for the two situations above, which is very similar to CDC's recommendation of re-testing every 6-12 months.
CDC is more protective in its recommendations for employees in the "high" risk category. These employees are recommended to be re-tested every 3 months. OSHA does not have a requirement for re-testing employees every 3 months. However, after an exposure incident, OSHA requires that a skin test be administered as soon as feasible and again 3 months after the exposure incident, if the first skin test is negative. Since it is possible that an exposure incident(s) could be the type of event that would cause an employee(s) to be included in the "high" risk category as defined by CDC, OSHA requirements, to some extent, track the CDC recommendations for a higher frequency of periodic skin testing.
With regard to two-step testing, both OSHA and CDC require or recommend two-step testing at the time baseline skin testing is administered. Also, both OSHA and CDC add that two-step testing is not necessary if the employee has had a documented negative skin test within the last 12 months. CDC is different from OSHA in that its Guidelines imply that two-step testing can be discontinued if there is evidence of a low frequency of boosting in the facility. OSHA's proposed standard does not allow such an exemption, i.e., for each employee who must have a baseline skin test at the time of the initial medical examination, the skin test must include a two-step test unless the employee has a documented negative test within the last 12 months, regardless of the frequency of boosting in the facility. The value of two-step skin testing is that it enables one to distinguish true conversions from boosted reactions. OSHA believes that this is important to know for each employee because if the employee is incorrectly identified as having converted, he or she may needlessly be subjected to preventive therapy that may have toxic side effects of its own. Since it is important to know the true skin test status for each employee, OSHA has preliminarily concluded that it is inappropriate to allow the overall frequency of boosting among employees in a facility to dictate whether any one employee receives two-step testing at the time of his or her baseline testing.
Respiratory Protection
OSHA requirements and CDC recommendations for respiratory protection are very similar. A respirator is a personal protective equipment device worn over the nose and mouth of the employee that filters certain airborne contaminants from the inhaled air. OSHA has adopted CDC's performance criteria for respirators appropriate for use for TB. Also, both OSHA and CDC have similar requirements or recommendations that respirators be worn when entering an isolation room, when performing cough-inducing procedures or aerosol-generating procedures on an individual with suspected or confirmed infectious TB, when repairing or maintaining air systems that may contain aerosolized M. tuberculosis, when transporting an individual with suspected or confirmed infectious TB in an enclosed vehicle and when working in a residence where an individual with suspected or confirmed infectious TB is known to be present. However, OSHA also requires that respirators be worn when employees are transporting individuals with suspected or confirmed infectious TB within the facility if those individuals are not masked (e.g., a surgical mask or a valveless respirator). CDC does not have a similar recommendation for respiratory protection while transporting individuals within the facility, but CDC does recommend, and assumes to some extent, that individuals with suspected or confirmed infectious TB are masked whenever they are outside an isolation room. In addition, OSHA requires that respirators be worn when employees work in an area where an unmasked individual with suspected or confirmed infectious TB has been segregated or otherwise confined. For example, this provision would cover employees such as those who work in admitting areas and must attend to unmasked individuals with suspected or confirmed infectious TB while those individuals are awaiting transfer. These types of employees are likely to be found in facilities that would meet CDC's definition of "minimal" risk. CDC states that respiratory protection is not necessary for employees in the "minimal" risk category. However, again, CDC recommends that if an individual with suspected or confirmed infectious TB is identified in a "minimal" risk facility, the individual should be masked while he or she is awaiting transfer to another facility, thus obviating the need for respiratory protection. OSHA, on the other hand, cannot require employers to mask clients or patients in a facility, and the Agency must therefore include provisions for respirator use to protect potentially exposed employees. However, consistent with CDC, OSHA proposes not to require respirators where the employer elects, as a part of his or her own administrative policies, to mask individuals with suspected or confirmed infectious TB. Thus, when individuals with suspected or confirmed infectious TB are masked while they are awaiting transfer to another facility or while they are being transported within the facility, employees would not be required by the standard to wear a respirator.
In some instances, the CDC may be more protective than OSHA with regard to respiratory protection. The CDC states that the facility's risk assessment may identify selected settings where the estimated risk of transmission of M. tuberculosis may be such that a level of respiratory protection exceeding the standard performance criteria is appropriate (e.g., more protective negative pressure respirators, powered air purifying respirators). The examples given of such selected settings are a bronchoscopy performed on an individual suspected of having TB and an autopsy performed on a deceased person suspected of having had active TB at the time of death. OSHA does not have a similar requirement for more protective respiratory protection. Respirators meeting the minimal performance criteria laid out by the standard would be required by OSHA for employees performing all high-hazard procedures, including bronchoscopies and aerosol-generating autopsy procedures.
IV. Health Effects
Introduction
For centuries Tuberculosis (TB) has been responsible for the death of millions of people throughout the world. It was not until 1882, however, that Robert Koch identified a species of bacteria, Mycobacterium tuberculosis (M. tuberculosis), as the cause of TB.
TB is a communicable disease that usually affects the lungs. The airborne route is the predominant mode of transmission, a situation created when individuals with infectious TB discharge the bacilli from the lungs when coughing, sneezing, speaking or singing. Some individuals who breathe contaminated air become infected with TB. Most often, the immune system responds to fight the infection. Within a few weeks, the infected lesions become inactive and there is no residual change except for possible lymph node calcifications. These individuals will have a positive skin test result. They will harbor the infection for life. At some time in the future, the infection can progress and can become an active disease, with pulmonary infiltration, cavitation, and fibrosis, possibly causing permanent lung damage and even death. With some exceptions, however, TB is treatable with antimicrobial drugs. If the active TB is treated early, there will be minimal residual lung damage. For this reason, individuals who have a TB exposure incident and develop a TB infection are treated to prevent progression to active TB disease.
With the introduction of antimicrobial drug treatment in the 1940s and the creation of programs in the United States such as the U.S. Public Health Service's Tuberculosis Program, there began a decline in the incidence of active TB cases in the U.S. From 1953, when active cases began to be reported in the U.S., until 1984, the number of annual reported cases declined 74 %, from 84,304 (53 per 100,000) to 22,255 (9.4 per 100,000) (Ex. 7-50). However, this steady decline in TB cases did not continue. Instead, from 1985 through 1992, the number of reported TB cases increased 20.1 % from 22,201 to 26,673 (10.5 cases per 100,000) (Ex. 6-13).
This resurgence in TB brought to attention a number of problems in the existing TB control programs. The direction of resources to areas with the highest increase in active cases has caused this increase to decline. The number of cases reported for 1995 indicates that the rate of active TB has returned to its 1985 levels. In 1995, a total of 22,813 cases of TB (8.7 per 100,000) was reported to CDC (Ex. 6-34). While this represents a decline in active TB, the 1995 rate is still two and one half times greater than the target case rate of 3.5 per 100,000 for the year 2000 and approximately 87 times the goal of less than one case per million population by the year 2010 proposed by the Advisory Committee on the Elimination of Tuberculosis (Ex. 6-19).
TB continues to be a national problem. Each year, cases of active disease are reported in every state in the Nation and in a substantial majority of counties nationwide. CDC estimated in 1990 that approximately 10 million people were infected with the tuberculosis bacterium and that approximately 90 % of the new cases of active disease that arise in the United States come from this already infected group (Ex. 7-52). Given the recent resurgence of TB, it is likely that a new population of individuals has been infected as well. Of great concern are strains of M. tuberculosis that have emerged that are resistant to several of the first-line anti-TB drugs normally used to treat TB infection and disease (e.g., isoniazid and rifampin). This drug-resistant form of the disease, referred to as multidrug-resistant TB or MDR-TB, is more often a fatal form of TB due to the difficulty in finding antimicrobial drugs to stop the bacteria's growth and progressive tissue destruction. In addition, individuals with MDR-TB often remain infectious for longer periods of time due to delays in diagnosing resistance patterns and initiating appropriate treatment. This, in turn, increases the risk that infectious individuals will transmit the organism to other persons coming in contact with them.
Most of the decreases in reported cases of TB since 1992 have occurred in areas such as New York City, where resources have been invested to improve or initiate TB control provisions, such as those outlined in OSHA's proposed standard. However, the 1995 statistics show that over the course of four years there is substantial variability in the increases and decreases of cases reported by each state for any given year (Ex. 6-34). In 1995, 15 states reported an increase in the number of TB cases compared with 1994. In addition, a recent study has shown that MDR-TB has spread to patients in Florida and Nevada, and to health care workers in Atlanta, Georgia and Miami, Florida. Moreover, one individual with MDR-TB infected or caused disease in at least 12 people in a nursing home in Denver, Colorado (Ex. 7-259). This study shows very clearly the ability of TB to be spread to different areas of the country. This is to be expected given the mobile nature of today's society and the frequency with which people travel. Immigration also contributes to the incidence of the disease. For example, while the number of active TB cases has decreased among U.S. born persons, the number of foreign born persons reported with TB has increased 63 % since 1986, with a 5.4 % increase in 1995 (i.e., from 7,627 cases in 1994 to 8,042 cases in 1995). Thirty to fifty percent of these cases were diagnosed 1 to 5 years after the individual enters the U.S. (Ex. 6-34). Thus, tuberculosis continues to be a public health problem throughout the United States.
The following discussion will briefly describe the basic concepts and terminology associated with TB as well as common factors that facilitate its transmission from one individual to another. This discussion will also include a review of studies relating to the occupational transmission of TB.
Background
TB is a contagious disease caused by the bacterium M. tuberculosis. Infection is generally acquired by the inhalation of airborne particles carrying the bacterium. These airborne particles, called droplet nuclei, can be generated when persons with pulmonary or laryngeal tuberculosis in the infectious state of the disease cough, sneeze, speak or sing.
In some individuals exposed to droplet nuclei, tuberculosis bacilli enter the lung and establish an infection (Ex. 7-52). Once in the alveoli, the tuberculosis bacilli are taken up by alveolar macrophages and spread throughout the body by the lymphatic system, until the immune response limits further growth (usually a period of two to ten weeks). In most cases the tuberculosis bacilli are contained by the immune response. Macrophage cells engulf the bacteria, which limits the spread of the bacilli. Initial lesions from infection heal; however, small calcifications called tubercles are formed and may remain a potential site of later reactivation.
Individuals in this state are infected with TB. They will show a positive skin test and they are at risk of developing active TB, a risk they carry throughout their lifetime. In many cases, as described below, preventive therapy is initiated with anti-TB drugs to prevent the progression to active TB disease. These drugs are toxic and may cause adverse effects such as hepatitis. Severe preventive therapy-associated hepatitis cases have necessitated liver transplants and in some cases have resulted in death (Ex. 6-10).
When the bacilli are not contained by the immune system, they continue to grow and invade the tissue, leading to the progressive destruction of the organ involved, which in most cases is the lung, i.e., pulmonary tuberculosis. The inflammatory response caused by the disease produces weakness, fever, chest pain, cough, and, when blood vessels are eroded, bloody sputum. Also, many individuals have drenching night sweats over the upper half of the body several times a week (Ex. 5-80). The extent of disease varies from minimal symptoms of disease to massive involvement with extensive cavitation and debilitating constitutional and respiratory symptoms. Since tuberculosis bacilli are spread throughout the body after the initial infection, other organs may also be infected and disease may occur at sites outside the lung, i.e., extrapulmonary tuberculosis.
There are two general stages of TB, tuberculosis infection and active tuberculosis disease. Individuals with tuberculosis infection and no active disease are not infectious. These tuberculosis infections are asymptomatic or subclinical and are only detected by a positive response to a tuberculin skin test. However, there are some individuals whose immune system is impaired and cannot mount a sufficient response to skin test antigens, i.e., they are anergic. Such individuals may be infected, although they do not show a positive response to the skin test. Individuals with tuberculosis infection and no disease would have negative bacteriologic studies and no clinical or radiographic evidence of tuberculosis disease. However, these individuals are infected for life and are at risk of developing active TB in the future.
Anti-tuberculosis drugs may be used for individuals with TB infection but who do not have active disease. In these cases, the antimicrobials are used as preventive therapy to prevent the onset of active disease. Because of the toxicity associated with the antimicrobials, preventive therapy may not be appropriate for all infected individuals. Various factors are considered to determine whether an infected individual is an appropriate candidate for preventive therapy (e.g., age, immune status, how recently the infection occurred, and other high-risk factors associated with TB) (Ex. 7-52, pg. 17). Isoniazid is currently the only drug that has been well tested in humans for its efficacy as preventive therapy (Ex. 7-50, pg. 61). However, serious side effects may result from isoniazid. A study in New York for the years 1991 to 1993 examined cases of hepatitis induced by isoniazid preventive therapy. In this study, 10 patients undergoing preventive therapy for TB were identified at a transplant center. Eight of these patients had developed hepatitis from isoniazid. Five received a liver transplant; the other three died while awaiting a liver donor. In addition, one of the transplant patients died after transplantation. Thus, preventive therapy may carry considerable risks for infected individuals.
In those cases where isoniazid cannot be tolerated by the patient or where it is suspected that infection resulted from exposure to isoniazid-resistant strains of M. tuberculosis, rifampin may be recommended for preventive therapy. Considerations for such alternative drug therapies are made on a case-by-case basis by the health care provider based on the medical and case history of the infected patient. Rifampin has adverse side effects as well. However, preventive therapy using rifampin has not been followed as well as that involving isoniazid and therefore, its side effects are less well characterized.
Individuals with active TB have clinical and/or radiographic evidence of disease. The initial laboratory method for diagnosing TB is the Acid Fast Bacilli (AFB) smear. This is a quick and easy technique in which body fluids, typically sputum samples, from individuals with suspected TB are examined for mycobacteria. However, this type of test only permits a presumptive diagnosis of TB since the test cannot distinguish between tuberculosis mycobacteria and other non-tuberculosis mycobacteria. Chest X-rays may also be used to diagnose active TB; however, some individuals with TB may have X-ray findings that are atypical of those usually associated with TB (e.g., HIV infected individuals). The diagnosis of clinically active TB is most definitively established by the isolation of M. tuberculosis in culture. However, it may take three to six weeks or longer from obtaining a culture to getting a result.
Individuals with active TB disease may be infectious, especially if they are untreated or inadequately treated and if the disease is in the lungs. The clinical symptoms of pulmonary TB include loss of appetite, weight loss, fatigue, fever, night sweats, malaise, cough with productive sputum and/or blood, and chest pain. The extent of the disease varies from very minimal symptoms to extensive debilitating constitutional and respiratory symptoms. If untreated, the pulmonary TB follows a chronic and progressive course in which the tissue is progressively destroyed. It has been estimated that approximately 40 to 60 % of untreated cases result in death (Exs. 5-80, 7-50, and 7-66). However, even among cured cases of TB, long-term damage can result, including impaired breathing due to lung damage (Ex. 7-50, pg. 31).
Approximately 90 % of immunocompetent adults who are infected do not develop active TB disease. However, for 10 % of infected immunocompetent adults, either directly after infection or after a latency period of months, years or even decades, the initial infection progresses to clinical illness, that is, active TB (Ex. 4B). The risk of developing active TB is increased for individuals whose immune system is impaired (i.e., immunocompromised). Such individuals include persons undergoing treatment with corticosteroid or immunosuppressive drugs (e.g., persons with organ transplants or persons undergoing chemotherapy for cancer), persons suffering from malnutrition or chronic conditions such as asthma and emphysema, and persons infected with the human immunodeficiency virus (HIV).
The main first-line drugs currently used to treat active TB are isoniazid, rifampin, pyrazinamide, ethambutol and streptomycin. Combinations of these antimicrobials are used to attack the tuberculosis bacilli in the body. Recommended treatment regimens include two or more drugs to which the bacilli are susceptible, because the use of a single drug can lead to the development of bacilli resistant to that drug (Ex. 5-85). Treatment with these first-line drugs involves a two-phase process: an initial bactericidal phase for the quick elimination of the bulk of bacilli from most body sites and a longer-term sterilizing phase for eliminating the remaining bacilli.
Different regimes of drug treatment (i.e., the types of drugs and frequency of administration) are recommended depending on the medical history of the patient involved and the results of drug susceptibility testing. The U.S. Public Health Service has recommended options for the initial therapy and dosage schedules for the treatment of drug-susceptible TB (Ex. 4B). While these antimicrobials are effective in the treatment of active TB, some of these drugs also have toxic potential. Adverse side effects of these drugs include hepatitis, peripheral neuropathy, optic neuritis, ototoxicity and renal toxicity (Ex. 7-93). Thus, patients undergoing TB therapy must also be monitored for drug toxicity that may occur from anti-tuberculosis drugs.
Individuals with active disease who are infectious may need to be hospitalized in order to provide isolation so that they will not infect other individuals. After the initiation of treatment for active TB, improvement of the disease can be measured through clinical observations such as loss of fever, reduction in coughing, increased appetite and weight gain. A reduction in the number of bacilli in sputum smears also indicates improvement. Three consecutive negative sputum smears generally indicate that the individual is no longer infectious. However, decisions about infectiousness are usually determined on a case-by-case basis after taking a number of factors into consideration, such as the presence of cough, the positivity of sputum smears, and the status or response to chemotherapy. Although no longer infectious to other individuals, the individual undergoing treatment still has tuberculosis disease and must continue treatment. Discontinuing or erratically adhering to the treatment regime can allow some of the bacilli to survive such that the individual will be at risk of becoming ill and infectious again (Ex. 7-52, p. 25).
Not all strains of the tuberculosis bacilli are susceptible to all of the antimicrobials used to treat TB. In some instances, drug-resistant forms of M. tuberculosis may emerge. Drug resistance may emerge by 1 of 3 mechanisms (Exs. 5-85; 7-50, pp. 44-47). Drug-resistant TB may occur naturally from random mutation processes, i.e., primary resistance. In addition, drug-resistant TB may result due to inadequate or erratic treatment, i.e., acquired resistance. In these cases, erratic or inadequate treatment allows the tuberculosis bacilli to become resistant to one or several of the drugs being used. Finally, drug-resistant TB may result due to the active transmission of drug-resistant TB from an individual already infected with drug-resistant strains of the tuberculosis bacteria, i.e., transmitted resistance. In recent years, drug-resistant forms of TB have emerged that are resistant to two or more of the first-line drugs used to treat TB, such as isoniazid and rifampin, two of the most effective anti-TB drugs. These drug-resistant forms of the disease are referred to as multidrug-resistant TB or MDR-TB. MDR-TB represents a significant form of drug-resistant TB from a public health standpoint, since its resistance to the first-line drugs used for therapy complicates finding adequate therapy regimens that will control the bacilli's growth.
Treatment of drug-resistant TB is determined on a case-by-case basis, using information from the patient's medical history and drug susceptibility testing. The recommended course of treatment will vary depending on the drugs to which the bacilli are susceptible. Compared to conventional TB drug therapy, MDR-TB, in general, requires more complex interventions, longer hospitalization and more extensive laboratory monitoring. The risk of death from such infections is markedly increased. For example, from January 1990 through September 1992, the CDC investigated eight outbreaks of MDR-TB. In these outbreaks, 253 patients were infected, of whom approximately 75 % died (Ex. 3-38-A). Many of these were immunocompromised due to infection with HIV. The interval from the time of TB diagnosis to the time of death ranged from 4 to 16 weeks, with a median time of 8 weeks.
Factors Affecting Transmission
A number of factors can influence the likelihood of acquiring a tuberculosis infection: (1) The probability of coming into contact with an individual with infectious TB, (2) the closeness of the contact, (3) the duration of the contact, (4) the number of tuberculosis bacilli in the air, and (5) the susceptibility of the uninfected individual. Several environmental conditions can influence the likelihood of infection. For example, the volume of shared air space, the amount of ventilation, the presence or absence of sunlight, the humidity and the crowded nature of the living quarters. These types of factors will affect the probability of acquiring a tuberculosis infection after being exposed to an individual with infectious TB. MDR-TB is not more contagious than drug-susceptible forms of the disease. However, due to time delays in diagnosing resistance patterns and initiating adequate treatment, individuals with active MDR-TB may remain infectious for longer periods of time. Consequently, the likelihood that they will infect other noninfected individuals is increased.
Once infection occurs, other factors may influence the probability of progressing to the active form of disease. As previously discussed, 10 % of immunocompetent adults infected with TB develop active TB. Three to five percent of untreated immunocompetent adults develop active TB within the first year after infection (Ex. 7-50, pg. 30; 7-52). Thus, recently infected individuals have the highest risk of developing active TB. This risk is increased for individuals whose immune system is impaired (e.g., persons being treated with immunosuppressive or glucocorticoid drugs, persons with chronic conditions such as asthma or emphysema or persons infected with the HIV). The probability of developing active disease can also be influenced by other conditions that may alter immune function such as overall decreased general health status, malnutrition, and increasing age.
The resurgence of TB in the United States from 1985 to 1992 has been attributed to a number of interacting factors: (1) The inadequate control of disease in high prevalence areas; (2) the increase in poverty, substance abuse, poor health status and crowded substandard living conditions; and (3) the growing number of inmates, residents of homeless shelters, elderly persons in long-term care facilities, persons with HIV infection and immigrants from countries with a high prevalence of TB infection (Ex. 7-50). This increase has begun to decline, with the 1995 case levels approaching the 1985 levels. However, a main reason for this decrease is the implementation of TB control measures, like those proposed in this standard, in selected areas of the country such as New York City. OSHA believes that implementation of such measures is necessary to prevent a resurgent peak such as that observed from 1985 to 1992 and to realize the goal set out by the National Advisory Committee for the Elimination of Tuberculosis. The following discussion describes some of the health effects data related to occupational exposure to TB and illustrates how the presence of TB control measures influences TB infection and disease.
Occupational Exposure
Exposure to TB in the health care setting has long been considered an occupational hazard. With the steady decline in reported TB cases from 1953 to 1985, some of the concern for occupational exposure and transmission also declined. However, from 1985 to 1992 the number of reported cases of TB increased. In addition, in recent years, several outbreaks of TB among both patients and staff in hospital settings have been reported to the CDC. These outbreaks have been attributed to several factors: (1) Delayed recognition of active TB cases, (2) delayed drug susceptibility testing, (3) inadequate isolation of individuals with active TB (e.g., lack of negative pressure ventilation in isolation rooms, recirculation of unfiltered air, and allowing infectious patients to freely move in and out of isolation rooms), and (4) performance of high-risk procedures on infectious individuals under uncontrolled conditions (Ex. 7-50). In addition to hospitals, outbreaks of TB have also been reported among the patients, clients, residents and staff of correctional facilities, drug treatment centers, homeless shelters and long-term health care facilities for the elderly. The factors contributing to the outbreaks in these other occupational settings are very similar to those factors contributing to the outbreaks in hospital settings (i.e., delayed recognition of TB cases and poor/inadequate ventilation for isolation areas).
The following is a discussion of some of the studies that have examined occupational transmission of TB. A large proportion of the available information comes from exposures occurring in hospitals, in part because this occupational setting has been recognized for many years as an area of concern with regards to the transmission of TB. However, in more recent years this concern has spread to other occupational settings which share factors identified in the hospital setting as contributing to the transmission of disease. The following sections will include a discussion of some of the historical data from the hospital setting, as well as the more recent data that have been developed in hospitals and other occupational settings where the transmission of TB has occurred as a result of the recent resurgences in the number of active TB cases.
Hospitals -- Prior to 1985
Even prior to the recent resurgence of TB in the general population, studies have shown an increased risk of transmission of TB to health care workers exposed to individuals with infectious TB. These studies clearly demonstrate that in the absence of appropriate TB control measures (e.g., lack of early identification procedures, lack of appropriate engineering controls), employees exposed to individuals with infectious TB have become infected and in some cases have developed active disease.
In 1979, Barrett-Connor (Ex. 5-11) examined the incidence of TB among currently practicing physicians who graduated from California medical schools from approximately 1950 to 1979. Through mailed questionnaires, physicians were asked to provide information that included their year of graduation from medical school, BCG vaccination history, history of active TB, results of their tuberculin skin testing, and the number of patients they were exposed to with active TB within the past year. They were also asked to classify themselves as tuberculin positive or negative and to indicate the year of the last negative and first positive tuberculin test.
Of the 6425 questionnaires mailed out, 4140 responses were received from currently practicing physicians. Twelve percent of the physicians had received the BCG vaccine. Sixty-one percent of the unimmunized physicians, who also had no history of active tuberculosis, considered themselves to be tuberculin negative. A total of 1542 (42 %) reported themselves as having a positive response to the tuberculin skin test, with approximately 44 percent of those tuberculosis infections occurring before entering medical school. Of those infections occurring before entering medical school, approximately eight percent were reported as having been a result of contact following work experience in the hospital prior to entering medical school. For those physicians infected either during or after medical school, the sources of infection were reported as occurring as a result of a known patient contact (45.1 %), an unknown contact (41.5 %) and a non-patient contact (13.4 %). In some cases, the nonpatient contact was reported as another physician or another hospital employee. Approximately one in ten of the physicians infected after entry into medical school developed active TB disease.
The authors also examined the incidence of infection, measured as the conversion rates in those remaining negative at the end of different time intervals (e.g., the last three years of medical school and five to 10 years after graduation). This examination indicated that from 1950 to 1975, there was a 78 % decrease in tuberculin conversion rates despite the expanding pool of susceptible medical students (i.e., an increasing number of medical students who were tuberculin negative). Yet despite this overall decrease in infection rates over a 25 year period, tuberculin conversion rates among recent graduates exceeded 1 % per year and age-specific infection rates among all the physicians studied were more than twice that of the U.S. population at comparable ages. The authors did not obtain information from the physicians on what type of infection control measures were being used in the facilities where they acquired their infections.
A similar analysis by Geisleler et al. (Ex. 7-46) evaluated the occurrence of active tuberculosis among physicians graduating from the University of Illinois medical school between the years 1938 and 1981. This study, also conducted by questionnaire, reported that among 4575 physicians questioned, there were 66 cases of active TB, of which 23 % occurred after 1970. Sixty-six percent of the cases occurred within 6 years of graduation. In addition, the authors reported that in most years the incidence of TB was greater among these physicians than the general population.
Weiss (Ex. 7-45) examined tuberculosis among student health nurses in a Philadelphia hospital. From 1935 to 1939, before the introduction of anti-TB drugs and the beginning of the general decline of TB in the United States, 100 % conversion rates were observed among those students who were initially tuberculin negative. For example, of 643 students admitted, 43 % were tuberculin negative. At the end of only 4 months, 48 % were tuberculin positive. At the end of 1 year, 85.9 % were tuberculin positive and by the end of the third year 100 % were positive. Of those students who converted during their student nursing tenure, approximately 5 percent developed active TB disease.
A decline in the rate of infection was observed over the next 36 years among student nurses at this hospital. The rates of infection were followed for ten classes of student nurses from 1962 to 1971. The students had little contact with patients during their first year but spent 4 weeks of their second year of training on the tuberculosis wards. Among those students initially tuberculin negative, the average conversion rate was 4.2 % over the nine year period, ranging from 0 to 10.2 %. Of the students who converted, 0.6 % developed active TB disease. The authors attributed the decreases in conversion rates to not only the general decrease in TB disease in the community, but also to the increased efficiency of surveillance of patients entering the hospital for the early identification of potential cases of TB and the increased efficiency of isolation for TB patients. Despite the dramatic decreases in conversion rates among these student nurses, conversion rates were observed at levels as high as 10 % for a given year, indicating that while the infection rates had decreased substantially since 1939, there still remained a significant amount of occupational transmission of TB in 1971. Moreover, this study shows that short term exposure, i.e., 4 weeks, is capable of infecting hospital employees.
Similar rates of conversion among hospital employees initially tuberculin negative were observed in a 1977 study by Ruben et al. (Ex. 7-43) which analyzed the results of a tuberculin skin testing program 31 months after its inception at a university hospital in Pittsburgh. Of 626 employees who were tested twice with the tuberculin skin test, 28 (4.5 %) converted from negative to positive. The employees were classified as either having a "presumed high degree of patient exposure" or a "presumed low degree of patient exposure". Employees presumed to have high patient exposure included nurses, X-ray and isotope laboratory personnel and central escort workers. Employees presumed to have low exposure included secretaries, persons in housekeeping and dietary work, and business office, laundry and central supply personnel. The rates of conversion for employees with presumed high exposure (6 %) and for employees with presumed low exposure (8 %) were not significantly different. However, this study excluded physicians and medical and nursing students. These groups of employees would also presumably have had high exposure to patients since they are often the hospital staff most directly involved in administering patient care. Had these employees been included the number of conversions among employees with presumably high exposure may have been significantly increased.
The study was not designed to determine the source of exposure for any of the employees who converted. However, the authors suggested that the high level of conversions among those employees with presumed low exposure to patients may have resulted from exposures at home. A majority of this group was comprised of housekeeping staff who were of low socio-economic status. The authors also suggested that unrecognized cases of tuberculosis may be playing an important role in the occupational transmission of TB in the hospital.
Unrecognized cases of TB have been shown to play a significant role in the outbreak of TB in a general hospital. In 1972, Ehrenkranz and Kicklighter (Ex. 5-15) reported a case study in which 23 employees converted after exposure to a patient with an undetected case of tuberculosis bronchopneumonia. In this study, the source case was an individual who was admitted to the emergency room with pulmonary edema. Upper lobe changes of the lung were noted in the chest X-ray, and TB was mentioned as a possible cause. However, no sputum cytology was conducted. The patient spent 3 hours in the emergency room, 57 hours in a private room and another 67 hours in intensive care until his death. Treatment of the patient included intubation with an endotracheal tube and vigorous nasotracheal suctioning. It was only upon microscopic examination of tissue samples of the lung and lymph nodes after the autopsy of the patient that tuberculosis mycobacteria were detected.
Employees who worked in the emergency room, the intensive care unit and on the floor of the private room (NW 3) and who were also tuberculin negative before the admission of the patient, were retested to detect possible conversion. In addition, 21 initially tuberculin negative employees on an adjacent floor (NW 2) were also retested. Of the 121 employees tested, 24 were identified as having converted to positive status (21 working on NW 3, 2 working in the intensive care unit and 1 working on NW 2). No conversions were observed among those working in the emergency room.
The employees who were retested were classified as either having close contact (e.g., providing direct care), little contact (e.g., more distant contact), unknown contact (e.g., no record or recollection of contact) or indirect contact (e.g., in the same room a day or two after the patient's stay). Conversions occurred in 50 % (13 of 26) of those employees with close contact, 18.5 % (6 of 33) of those with little contact, 21.4 % (3 of 14) of those with unknown contact and 3.7 % (1 of 29) of those with indirect contact.
While the majority of conversion