The Ramazzini Institute
for Occupational and Environmental Health Research   

Who Are We?

Risk Managers Ask
When Is Asbestos Exposure Hazardous?

     On September 18, reflecting a worldwide movement to ban the use of all forms of asbestos, the World Trade Organization in Geneva supported the French ban on the import of asbestos from Canada. The WTO decision was hailed not only in the European Union, whose member countries are moving toward a total ban, but also in the United States as an important breakthrough in environmental protection, pointing to a post-Seattle attitude in the rapid globalization of national economies.

     Attention to new sources of asbestos may obscure another, perhaps more important threat: asbestos-in-place. Should it be removed? When is it hazardous? Some answers may be found in an unusual forum: a wage dispute.

     Twenty-eight years after a successful petition for an asbestos standard was filed with the Occupational and Safety Administration by the AFL-CIO, the first under what was then a new act, many government facilities - shipyards, office and storage buildings, mines and production facilities - remain contaminated with asbestos.

     The May 28th issue of Stars and Stripes, reported that Don Mize, a union safety officer blew the whistle on conditions in four army camps in South Korea alone, where 78 known and suspected asbestos spills have taken place in family housing, barracks and other buildings, along with 230 mostly “illegal” removal and repairs. In the Corpus Christi, Texas, Army Depot, an independent arbitrator awarded government workers $49 million in back hazard pay based on exposure to asbestos and the risk of disease ranging from cancers to asbestosis.

     In the Texas facility, falling chunks of asbestos insulation, according to sworn testimony, hit the heads of workers. Instead of removal, insulation was repaired with masking tape. Some workers have become ill with asbestos-associated disease.

     The right of government blue collar workers exposed to asbestos to receive hazardous duty pay for working in contaminated facilities, however, has been challenged by a Department of Defense proposal to the Office of Personnel Management to eliminate the differential wages if the current OSHA standard is met. Members of AFL-CIO Metal Trades Councils, American Federation of Government Employees and the National Federation of Federal Employees affiliate of the International Association of Machinists are challenging the proposal.

     The controversy revolves around the contention of the Department of Defense that when the OSHA limit is met, the risk of disease has been “practically eliminated”.

     The term “risk”, or the chance of harm, is a statistical concept. To calculate risk, some arbitrary rules are used. One such rule frequently used in risk assessment is “statistical significance”, usually calculated at the 95% confidence level to reduce the chance of false-positive findings. But using this rule also means that, when used to judge studies of the relatively small populations that contract rare diseases like mesothelioma, a cancer usually associated with asbestos exposure, there is an increased chance of false negatives, i.e., there may be many more cases than is reflected in the risk estimates.

     New cases of asbestos-related disease continue to be found among government and government contractor employees, such as cases now being found among those who work in Department of Energy nuclear weapons production facilities. The very long latency or “silent” periods before asbestos disease appears in the clinic, sometimes 45 years after exposure, means that the epidemic of asbestos disease will continue to be found in federal facilities for many more years, even if today the government were to stop using asbestos and remove it from wherever it has been applied. .

     The unions contend that in addition to the issue of wage fairness, eliminating the hazard pay would mean that an important economic incentive for asbestos removal and clean workplaces would be eliminated. They believe that the asbestos problem is merely an index of broader environmental problems of poorly controlled work environments containing exposures to a range of hazardous agents in government facilities.

     What do the scientists say? The arbitrator in the Corpus Christi case heard from Dr. William Nicholson, Professor Emeritus of Community Medicine at Mt. Sinai School of Medicine in New York. Nicholson was a close colleague of the pioneer in the control of asbestos-related disease: Dr. Irving Selikoff. Nicholson used as a comparison with the work environments in question urban air.

     Ambient urban air, he estimates, contains sufficient asbestos to result in a lifetime risk of death by cancer of three [3] per 100,000. In the Corpus Christi Army Depot, Nicholson calculated, they were running risks of 40 to 90 per 100,000 or 400 to 900 per million. Usually risk levels over one [1] per million are considered excessive in community environments.

     An advisory committee of the Office of Personnel, chaired by John F. Leyden, is charged with making recommendations in the wage dispute. On July 20, the committee heard from OSHA’s Dr. Peter Infante.

     The preamble to the OSHA asbestos standard as amended in 1994 refers to a court decision [BCTD v. Brock], which cites a 1984 risk estimate by OSHA. The court noted that even at the permissible exposure limit proposed, which was adopted, the excess risk, i.e. the risk over and above what would be found for everyone in the ambient environment, “could well be found significant.” OSHA said their risk assessment showed that reducing exposure to 0.1-fibers/cubic centimeter, as a time-weighted average during a workday, would reduce, but not eliminate significant risk. The excess cancer risk at that level would be reduced to a lifetime risk of 3,400 cases expected to be found over and above what would be found in the ambient environment for every million workers, or 3,400 times the generally tolerated community level of environmental risk.

     Dr. Infante appeared to have been referring to the 1984 estimate when he noted the OSHA policy that one case in a thousand is a significant risk. He made clear that a significant health risk is “left behind” at the current OSHA standard, and that only the constraints of what the agency considers feasible in terms of monitoring and abatement prevented OSHA from setting a lower permissible exposure limit. Even when the levels are below the OSHA limit, both Nicholson and Infante made clear, a continually proven finding in large population studies is that a risk remains, because no completely “safe” [i.e., no non-adverse effect or threshold] level of exposure to cancer-causing agents is likely to exist.

     Some studies suggest that when workers and even bystanders or family members are exposed to any form of asbestos, at levels ranging from below detection by commonly used monitoring methods to visible dust, they continue to sicken and die from their exposures.

     It isn’t feasible to conduct studies at the very low levels of exposure below the OSHA limit, said Dr. Nicholson, but there is good evidence supporting the use of a “linear model” to predict an effect at levels that have not been studied, i.e., a straight line on a graph that helps the risk manager estimate at any dose what the effect will be. And, he emphasized, there are “no data that would indicate a threshold below which there is no risk.”

     Other scientists say that at very low levels the shape of the line isn’t straight, but curves [like a hockey stick.] These same scientists do not suggest, however, that the line breaks, i.e., that there is a threshold. From the point of view of risk management, however, the exact shape may not be important. In a Supreme Court decision [IUD vs. API] on the control of benzene that framed the existing methods of risk assessment, a plurality of the court established that in making risk management decisions, it is not necessary for the regulator to be bound by a mathematical straitjacket. The regulator can make judgments on the side of safety. Nor is it feasible to control precisely either the exposures or the risks, from either a monitoring or an abatement perspective. Only rough approximations can be made. In another court decision involving a group of 14 carcinogens, OSHA won the right to not have any numbers in the standard at all. Just the mere observed presence of the carcinogen in the workplace in any form or under any condition, not a numerical limit, triggers maximum control measures, including substitution of materials.

     Since the original petition for a standard was filed in 1972, a strong consensus in the scientific community has evolved, i.e., any exposure to asbestos other than zero is generally considered to be hazardous.