Critics charge proposed TB standard lacks scientific support

Some call for enforcement of CDC guidelines instead

Now that the U.S. Occupational Safety and Health Administra tion has unveiled its long-awaited proposed rule for preventing occupational exposure to tuberculosis,1 critics are attacking it as unnecessary and unscientific, supporters are defending the need for a federal regulation, and many others are still just trying to read through it.

Even officials at the Centers for Disease Control and Prevention are painstakingly working their way through the 148-page document, which includes a previously unreleased preamble containing a list of about 80 questions intended to guide commenters’ responses.

"We’re in the throes ourselves of trying to read this," says Linda Martin, PhD, TB lead and director of HIV activity for the National Institute for Occupational Safety and Health, a branch of the CDC. "We have a huge slew of people at CDC who deal with TB, and they are all looking at it. We still have to decide what points we want to comment on and whether we have enough data to address them."

In 1994, the CDC issued revised guidelines for preventing TB transmission in health care facilities.2 The guidelines contained provisions for risk assessments, respiratory protection, and medical surveillance, and it is in those areas that the proposed standard appears to differ most significantly from the CDC’s recommendations. Those are also the provisions that are drawing the most fire from critics.

While other organizations such as the American Association for Occupational Health Nurses (AAOHN) have not come out officially for or against the need for a TB standard, the leaders of one national group are foursquare against it.

Why not enforce CDC guidelines?

"The CDC guidelines have basically worked very well to bring [the risk of occupational TB infections] under control," says Eddie Hedrick, BS, MT(ASCP), CIC, chairman of the TB task force for the Washington, DC-based Association for Professionals in Infection Control and Epidemiology (APIC). "We’re down to the lowest incidence of TB since we first started monitoring tuberculosis in this country in 1953. We don’t need a whole new set of rules that differ from the CDC’s. The argument from OSHA is that not everybody has implemented the CDC guidelines, but our argument to them is, OK, let’s enforce them. Why can’t they just use the general duty clause and enforce the CDC guidelines?"

But officials of the Service Employees International Union (SEIU), one of several labor unions that lobbied for development of a standard, maintain that for the most part, not only does the proposed standard closely resemble the CDC guidelines, but it also is a necessity for adequate health care worker protection.

"Some health care institutions follow the CDC guidelines and some don’t," says William Borwegen, health and safety director for the SEIU in Washington, DC. "The ones that don’t are taking the low road, and that’s the purpose of the OSHA standard. A lot of our members — nurses and other health care workers — are emphatic that their employer will never, never, never implement these guidelines until they’re required to through the OSHA standard."

Borwegen says that beyond some "inevitable wording changes when you move from a guideline to something that’s enforceable," the proposed rule "fairly mirrors" the CDC version. In addition, infection control and occupational health practitioners are "shooting themselves in the foot" by opposing a standard because it would allow them to obtain more resources to deal with the problem, as happened with the bloodborne pathogens standard, he states.

Hedrick, who also is manager of infection control and staff health at the University of Missouri Hospital and Clinics in Columbia, counters that if a standard is inevitable, "it should be totally consistent with the CDC guidelines. If we’re going to have a standard, let’s make sure it is based on science and is one we can justify."

One of several provisions that APIC claims is not based on science is the risk assessment portion, which Hedrick says differs substantially from the CDC’s recommendation.

"The ones that the CDC wrote were based upon good scientific risk assessment and evaluation, but OSHA scuttled the whole concept of the risk assessment. They claim to have a risk assessment based on if you have less than one person who has TB in a county, then you don’t have to comply with 100% of [the standard], but that’s not scientific and it doesn’t make sense," he states.

OSHA, CDC perspectives differ

Hedrick says the differences between the proposed standard and the CDC guidelines can be attributed to OSHA’s industrial hygiene perspective vs. the CDC’s epidemiologic emphasis.

"The CDC’s risk assessment is too hard for OSHA to enforce," he maintains. "It means somebody has to think, and their inspectors aren’t trained to think in infectious diseases. They have an industrial hygiene background in mind, and they really don’t understand the difference between the industrial hygiene model of zero risk compared to the epidemiologic model that says I can take the risk no lower [than a certain level] because the person who puts you at risk of getting TB is usually the undiagnosed patient. They have not acknowledged that concept. It’s a chronic criticism ever since they got into bloodborne pathogens. You can’t put this [infectious TB] in a can as if it were a dangerous chemical, move it away from people, isolate it, and therefore have zero risk. You can’t do that with a moving target — a human being with an undiagnosed disease."

The proposed rule’s employee skin-testing provisions also lack sound scientific support, Hedrick charges. He says APIC is particularly opposed to the OSHA-proposed mandate for retesting every six months for many employees with occupational exposure, compared with the CDC’s recommendation for annual retesting of employees in low-risk categories and every six to 12 months for those in intermediate-risk categories.

"Logistically, that’s basically an impossibility for most of us," he says. "It’s hard enough to get people down once, but now they’re going to double that frequency, and it’s not based on any rationale. The reason CDC specified six to 12 months is that they based the increased frequency on conversion rates or risk in your facility after you do your risk assessment. They gave us the opportunity to increase it if we need to, but for the most part the minimum is one year. To make people do this twice a year makes no scientific sense."

In addition, APIC opposes the proposed standard’s requirement for two-step skin-testing for all new hires. The CDC recommends it as well, but adds that it can be discontinued if booster skin-testing in a facility determines it’s not beneficial. Hedrick says five years of booster testing at his facility did not produce any boosting, so now the only new hires booster skin-tested are those who are foreign-born, older, or from a high-risk background.

APIC also disputes the need for skin-testing all employees 30 days before they leave a hospital’s employ.

"I have no idea why [OSHA] included that or how they expect it to be done," Hedrick says. "In my business, if you get two weeks’ notice, you’re lucky. Secondly, why? They say they want people to know before they leave your employ if they’re infected or not, so why not just specify that employees have the opportunity to be skin-tested before they leave your employment if they want to? That makes far more sense, even though I still don’t see any need for it. They assume any skin-test conversion for someone working in health care is related to their job, which is wrong."

Standard ‘confusing and costly’

The requirement for annual respirator fit-testing also has come under fire. Hedrick questions the need for protection beyond a surgical mask, but acknowledges that the requirement for N95 respirators is probably a foregone conclusion.

Nevertheless, N95s are disposable, moldable masks, he point out, which means "if I fit-test you right now, five minutes from now it might not fit you if you are moving around and talking." Instead of fit-testing, APIC favors teaching HCWs to fit-check whenever they don an N95 mask.

"The whole aspect of fit-testing is emphasizing the least important part of TB control at the greatest expense," says Hedrick.

In fact, the entire proposed standard is "nothing more than confusing, costly, and without any justification. If we do need a standard, it should be totally consistent with the CDC guidelines," he states.

But Amanda Edens, OSHA project officer for the tuberculosis rule, says much of the proposed standard is taken directly from the CDC guidelines. The differences generally can be attributed to OSHA’s emphasis on worker protection and its occupational safety and health perspective.

"We think the CDC guidelines work, too, but our concern is that not everybody follows them," Edens says. "There are a lot of commonalities, and where there are some differences, we can consider them. We’re putting this out on the table for people to look at, and if it doesn’t work we can certainly change it. To the extent that certain provisions are different, they’re probably employee-based, and we’re a little more conservative when we get to the employee. The CDC looks strictly at the issue of controlling TB, and not at the overall aspects of a safety and health program."

Edens says OSHA’s proposed risk assessment provisions are similar to the CDC’s in that they are both "logical, decision-tree" methods. If employers find OSHA’s requirement confusing, the agency might consider issuing a computerized risk assessment in a question-and-answer format that would help users comply. In addition, OSHA might develop a risk assessment flow chart similar to the CDC’s.

OSHA: ‘We could change it’

Skin-testing frequencies do vary somewhat from CDC recommendations but are not totally different, according to Edens. While the CDC advises retesting at three-month intervals for some high-risk workers, OSHA has no such provision. The proposal requires six-month retesting for some workers with higher exposure potential, and "some people don’t necessarily agree with that, but that’s the whole reason for having the rulemaking. We’ll listen to what they say, and if it’s a really convincing argument, we could change it," she says.

OSHA’s proposed mandate for two-step testing of new hires comes directly from CDC guidelines, she adds. The difference is that OSHA has tried to be "more conservative" by not allowing the frequency of boosting in a facility to determine whether an individual employee will be two-step tested.

"The reason we’re not going to allow frequency of boosting to get [new hires] out of two-step testing is that it’s always better for individual employees to know their true skin-test status," Edens explains. "They could be falsely identified as a new converter a year later, which would unnecessarily require employers to do follow-up, so there are advantages to both employers and employees. However, the cost-effectiveness issue is a legitimate concern."

Similarly, the provision for skin-testing employees 30 days before termination might not be feasible, either. Employees would benefit from knowing their skin-test status when leaving a job, and employers would benefit from knowing if employees are negative when they leave a hospital’s employ so they cannot come back later to claim workers’ compensation, she explains; however, "if it’s a bad idea, we can knock it out," she says.

Regarding the criticism that OSHA’s proposal takes an industrial hygiene perspective rather than an epidemiologic one, Edens says industrial hygiene principles of identifying and reducing exposures apply to any work setting.

"This is not our first foray into a health care setting," she states. "The bloodborne pathogens standard uses a lot of industrial hygiene principles, and we find they work very well. We have been and probably always will continue to be in the health care setting because of all the hazards there to workers."

Comments on the proposed standard were due Dec. 16, 1997, but at press time OSHA was considering extending the deadline into January 1998 at the request of several professional associations. Hearings were set to begin in February in Washington, DC, but may be extended to several other regional locations, as well. A final standard is not expected before 1999.

Meanwhile, the CDC plans to closely examine provisions in the proposed standard that differ from its 1994 guidelines.

"When OSHA writes a standard, it’s always a little different than what the CDC does because our recommendations are not regulatory," says Martin. "The CDC writes guidelines from a public health perspective, not a regulatory perspective. What we plan to do is look at the places where [the OSHA proposal] differs from the guidelines and determine if the approach that OSHA took is valid, but just not the approach we would have taken. Our goal is to review it for the science and see if we need to make suggestions."


1. Department of Labor. Occupational Safety and Health Administration. Occupational exposure to tuberculosis; proposed rule. Fed Reg 62; 54,159-54,307.

2. Centers for Disease Control and Prevention. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health care facilities, 1994. MMWR 1994; 43 (No. RR-13): 1-132.