Data vs. Experience: The Human Factor in OSHA's APF Proposal

April 8, 2004
Many welcomed OSHA's decision to add assigned protection factors (APFs) to its respiratory protection standard. But a key part of the proposal has aroused intense controversy over the use of scientific findings.

The public hearings to amend OSHA's respiratory protection standard (29 CFR1910.134), stretching over three days in January, were filled with enough technical data, acronyms and recondite debate to baffle an educated layman.

There was general agreement on the need to add APFs to the 6-year-old rule, and a rough consensus on most of the proposal's contents. But throughout the hearings, there also raged a debate over how much protection to assign the most popular form of respirator used in the workplace: the filtering facepiece. OSHA, relying on its data analysis, proposed an APF of 10 for filtering facepieces. Many experts, based on their field experience, argued this APF is too high and will endanger workers.

On one level, the dispute appeared to be the familiar one of labor pressing for a more protective decision, while most industry representatives argued the other side.

At a deeper level, the debate could be seen as a conflict between the relative roles of scientific data and professional experience, according to James Johnson, Ph.D., CIH, section leader in the hazards control department at Lawrence Livermore National Laboratory in Livermore, Calif.

"When you're looking at the real difference between the two sides," said Johnson, "the data folks are saying the only things that are appropriate to look at are scientific findings, whereas the other side looks at that data and applies professional judgment to it, based on their field experience."

One-Stop Shopping

Currently, employers have virtually no place to turn for guidance in selecting respirators. The American National Standards Institute's (ANSI) Z88.2 voluntary standard used to offer guidance on APFs, but the 1992 standard has been withdrawn, and its replacement is not yet issued.

The OSHA proposal will offer employers a single place to go to determine what level of respirator protection is appropriate for their workplace. As Steve Witt, director of OSHA's directorate of standards and guidance, explained at the hearings, the agency believes that incorporating the proposed APF table into the existing standard "will enhance the protection afforded to respirator users, while providing greater uniformity of requirements, improved compliance and reduced compliance burden." There is little debate over the APFs OSHA assigned to a variety of more protective respirators (see chart).

OSHA is also defining maximum use concentrations (MUCs), the maximum concentration of a hazardous substance against which a respirator can protect the user. Employers will use the MUCs to select appropriate respirators, especially for use against organic vapors. In addition, the proposal includes sections on respirator selection for certain substance-specific standards, such as lead, asbestos and cadmium, that have been scattered throughout these various rules.

Manufacturers, led by 3M Co. and the International Safety Equipment Association (ISEA), the National Institute for Occupational Safety and Health (NIOSH), plus some consultants, generally supported OSHA's proposal to assign an APF of 10 to all filtering facepieces and quartermasks, the same APF given to elastomeric half-mask respirators. (NIOSH, however, rejected giving a 10 to quartermasks.)

Opposing them were labor unions and a number of consultants associated with ANSI's respiratory protection subcommittee. These groups generally argued that filtering facepieces and the rarely used quartermasks deserve an APF of only 5.

NIOSH, with its many years of experience certifying and studying respirators, commended OSHA for the thoroughness of its research and analysis. "NIOSH applauds OSHA's efforts in conducting the evaluation of all the major peer-reviewed studies of simulated workplace protection factors (SWPFs) and workplace protection factors (WPFs)," commented Richard Metzler, director of NIOSH's National Personal Protective Technology Laboratory in Pittsburgh.

"We believe," OSHA's Witt concluded, "that our analyses are the most comprehensive that have been completed to date." Many experts, including those who, like Johnson, disagreed with OSHA's proposal, agreed.

What's the Problem?

Opponents of assigning a 10 to filtering facepieces made several arguments:

  • They questioned the quality and reliability of the data upon which OSHA relied in determining there's no verifiable difference in protectiveness between filtering facepieces and half-masks;
  • OSHA's proposal is based on the unrealistic assumption that employers using it will have a respirator program in full compliance with 1910.134;
  • Filtering facepieces generally do not fit people as well as elastomerics, and it is very difficult to do a user seal check on filtering facepieces, a requirement of the OSHA standard.

Jeff Weed, product manager for TSI Inc., a Shoreview, Minn. manufacturer of the PortaCount respirator fit tester, pointed out that "NIOSH certifies respirators, but they don't look at how well the respirator fits on people because the protocol does not include fit-testing."

Moreover, Johnson asserted that all of the studies OSHA analyzed to justify an APF of 10 on filtering facepieces are from before 1995, when NIOSH adopted 42 CFR Part 84, and dropped the fit-testing requirement for certification. Since that time, more than 300 filtering facepieces have come on the market.

At the hearing, Metzler promised NIOSH would develop a standard protocol for certifying a respirator "to assure it can fit a broad population of workers." In a later interview, Metzler confirmed that details of the new test have yet to be worked out, such as whether old respirators would be "grandfathered" and only new devices subjected to the test. He predicted it would require at least 1 year to develop the program.

"The question is," commented Johnson, "will market forces require NIOSH to do full rulemaking on these revised requirements? That could take 3 to 5 years."

Opponents of the OSHA proposal rejected the assumption that employers comply with 1910.134. According to a NIOSH-BLS survey released last year, a majority of responding employers indicated they are not following all the provisions of the standard.

Other experts questioned how well SWPF studies represent the real world. All agreed that studies conducted in the workplace (WPFs) alter the behavior of the workers who are being observed, distorting the results.

ANSI Threat?

While ANSI's full Z88 committee and the subcommittee charged with setting APFs approved a standard granting a 5 to filtering facepieces, manufacturers on the subcommittee have appealed, so the standard is not yet final. Some of the most compelling testimony and exchanges of the hearing were provided by members of the subcommittee (plus Johnson, who chairs the Z88 Secretariat) and those who questioned them.

A group from the ANSI subcommittee, including Timothy Roberts, CIH, a senior industrial hygienist at the Lawrence Livermore Laboratory, and consultants Mark Haskew, CIH, and Ching-tsen Bien, P.E., CIH, stressed that their committee debated for 7 years to reach a consensus that filtering facepieces deserved an APF of 5. They defended the ANSI position primarily because, in their professional judgment, it is difficult to do user seal checks on filtering facepieces and because these devices do not fit workers as well as half-face respirators.

One of those questioning the ANSI committee members was Warren Myers, Ph.D., M.P.H., who conducted many of the studies upon which OSHA relied in its rulemaking. Hired by the agency as an expert witness to defend its proposal, Myers is associate dean at West Virginia University's College of Engineering and Mineral Resources.

When Myers and OSHA officials asked what data supported changing the previous 1992 ANSI standard, in which filtering facepieces were given an APF of 10, Bien replied, "It's based on the quality of the data."

OSHA officials and Myers repeatedly asked the ANSI panel and all witnesses favoring an APF of 5 for filtering facepieces to provide hard data supporting their position. None were able to do so.

"In '92, the ANSI committee made their decisions based on a scientific analysis of the data," concluded Myers. "What I've heard today seems to me based more on the opinion of the committee than the data."

In an interview with Occupational Hazards, Myers explained why he placed himself in the "data" camp. "I don't share the opinion that you have to exercise professional judgment because these studies don't represent the real world," he contended. "We have now done dozens of workplace studies and when you look at them in the aggregate, they represent a lot of real world use."

After the hearing, Pat Tyson, an attorney representing 3M, questioned whether opponents of the OSHA rule based their judgment on experience, arguing that "judgment must be based on data and the data go the other way." Tyson, a former acting OSHA administrator and one of the most prominent OSHA lawyers in the nation, sat through all three days of public testimony, a sign of how important OSHA's decision is to 3M.

"I'm urging the agency to base its decision on facts and not emotions," Tyson said.

Because the ANSI standard is not yet final, it is not clear how much weight OSHA will give to it. It is clear, however, that 3M took the ANSI threat very seriously. In a rare move for an informal public hearing, Tyson lodged a motion to strike all references to the ANSI committee from the public record, because the ANSI standard is not yet final. Judge Thomas Burke denied Tyson's motion.

Dollars vs. Sense?

Respirator manufacturers may have a lot riding on OSHA's filtering facepiece decision. "No doubt 3M and other manufacturers make a lot of money selling filtering facepieces," commented Weed, in a sentiment echoed by other experts. "If OSHA reduces the APF to 5, I think they feel it would reduce their market."

AFL-CIO industrial hygienist Bill Kajola asserted that since filtering facepieces cost far less than elastomerics, most employers will choose the former if the two devices have the same APF.

"I don't know what the APF should be, but I feel very strongly that filtering facepieces and elastomerics should have a different APF," asserted Weed, who did not attend the public hearings because he said his company has no direct interest in the APF issue. "Filtering facepieces as a class do not achieve fit factors that are as high as elastomerics, so it's hard to believe they offer the same level of protection."

But Weed conceded he had no data only 17 years of experience with customers who fit-test respirators.

Andy Coats, president of OHD, a Birmingham, Ala. company that has done thousands of qualitative and quantitative respirator fit tests, agreed with Weed. "Elastomerics give a much better fit," he said.

OSHA regulations require that employers conduct quantitative or qualitative fit tests on all respirators used in the workplace, and the agency's proposal assumes all employers will comply. But in another exercise of experience-based professional judgment, or perhaps common sense, Johnson questioned this assumption. "Filtering facepieces cost as little as $1 each, and now you tell me [employers] have to buy a $10,000 PortaCount, or even [spend] $250 to do the far less effective qualitative fit testing?"

As OSHA weighs the testimony from the public hearing, it appears to be caught in a familiar dilemma. Its decision is likely to antagonize either labor or industry, and may be confounded by politics.

"There's a political component to this as well, although we don't usually like to address that," commented one observer. "Republicans usually don't like to put burdens on industry." Normally, nothing controversial gets done after April in election years, he added. "OSHA could be ready to go, but the administration might tell them, 'Don't rock the boat.'"

Weed expressed sympathy for OSHA's position. "What 3M is saying is that they have all these studies, and people who don't like filtering facepieces don't have data, all they have is anecdotal evidence. Unfortunately, OSHA is in the middle of that."

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