Document XRM7JXwG62rmaoLBoDGez38zg

Federal Register / Vol. 51, No. 119 / Friday, June 20,. 1966 / Rules and Regulations 22649 workers may be exposed throughout compared with the risk predicted for a different than the risks to employees their entire working lives, and reflects constant number of workers exposed for exposed to 2 f/cc in general industry. the view that OSHA is regulating a working lifetime. Such an increase in Another issue raised by the AIA/NA . workplace conditions and not specific absolute risk is a result both of the involved the effect of fiber type on employees. larger number of workers exposed to OSHA's risk estimate for asbestos- A second reason for using an asbestos for some period of time if related cancer. By not accounting for the assumption of lifetime exposure is that turnover is taken into account and the different carcinogenic potencies ofthe this method permits comparison of the non-linearity of the relationship various fiber types, the AIA/NA risks from asbestos exposure to the risks between exposure duration and maintained that the ". . . predicted risk posed by other substances that OSHA asbestos-related cancer risk. This is from mesothelioma is likely to be has regulated or proposes to regulate. illustrated in a technical report (Ex. 84- substantially over-estimated" (Ex. 328, Such comparisons are useful to the 405) submitted to the record by OSHA p. H7). The AIA/NA went on to state: Agency in ensuring that a consistent policy underlies OSHA's determinations of significant risk. Because the Agency, has determined significance of risk in showing that calculating risks taking employee turnover and less-thanlifetime exposure into consideration results in a larger number of predicted . .., OSHA's sole reliance on four studies where exposures were mixed, and were a large number of mesotheliomas were found, biases its risk assessment to the high side .previous rulemakings based on the asbestos-related cancer deaths than . . . Had OSHA relied on a more lifetime exposure assumption, the use of shorter exposure duration for calculating the risk of asbestos-induced disease would preclude the Agency from would be predicted using a model that assumes a lifetime exposure duration and no employee turnover. Therefore, OSHA finds that use of the lifetime representative set of studies showing the highest potencies, their mesothelioma risk ' estimate would have been reduced by a least half. (Ex. 328. p. 1-19) making such comparisons. As stated in exposure assumption does not result in OSHA discusses the health evidence for the April notice (49 FR14120), the an overstatement of the risk of mortality different fiber types in Section IV of this Agency has determined that exposure to from asbestos-related cancers. preamble. In that section, OSHA asbestos results in an excess disease This concept is particularly relevant concluded that, although risk that is many times that found for to the construction industry, which is epidemiological studies indicate that other hazardous agents that have been characterized by higher employee exposure to amphiboles is associated regulated by OSHA. turnover as compared to manufacturing with a greater mesothelioma risk than is OSHA also believes that the argument industries. One commenter. the exposure to chrysolite, animal studies made by the AIA/NA, that use of an Associated General Contractors of show the opposite effect. Several assumption involving a shorter exposure America (AGC) argued that OSHA's risk rulemaking participants suggested a duration would result in a reduction in estimates do not apply to the variety of reasons for this discrepancy. .risk, is invalid. OSHA's risk assessment construction industry because of the OSHA agrees with Dr. Davis (Tr. 7/10, p. shows that the total asbestos-related unique exposure patterns characteristic 65) that, on a fiber-by-fiber basis, there cancer risk is not linearly related to of that industry: are no data to show conclusively that duration of exposure, and that risk is not Many of the studies on the dangers of reduced proportionally when the asbestos have only limited implications for exposure durations used are reduced. the construction industiy. Forty-five years of The reasons for this effect are twofold: exposure to:2 f/cc of airborne asbestos may First, as the population of asbestos- . cause sixty-four excess cancer deaths per amphibole fibers are more potent than chrysotile fibers. For this reason. OSHA did not distinguish among fiber types when conducting the Agency's risk assessment. Furthermore, no evidence exposed workers ages, the proportion of one-thousand workers, but few if any was submitted to the record.to indicate this population dying form asbestos construction employees will ever experience . that such a fiber-type differential exists decreases because many of these individuals die from othor diseases that are related to aging. Second, the relationship between exposure duration and the risk.of dying of mesothelioma is not linear. Both of these elements such exposure. Very few employees will remain in the industry for forty-five years. Very few wit] even experience more than low level, intermittent exposure to asbestos. (Ex. 84-457. p'.l) OSHA recognizes that many for lung cancer risk, which constitutes the largest component of the total cancer mortality, risk predicted by OSHA's risk assessment. Moreover, even if OSHA agreed with the AIA/NA and used an estimate of mesothelioma contribute to the non-linearity of the construction employees are exposed on risk that was reduced by 50 percent, the relationship between exposure duration a less frequent basis than employees in risk of dying of asbestos-related cancer and the risk of incurring asbestos- general industry. However, OSHA continues to be significant even at the related cancer. The non-linearity of the disagrees with AGC's contention that new PEL of 0.2 f/cc: reducing the relationship between rjsk and duration the health evidence for asbestos has mesothelioma risk by half results in an is illustrated by comparing the total "limited applications" for construction excess of 5.3 asbestos-related cancer . ' asbestos-related cancer risk for a 45- employees. First, there are construction deaths per 1,000 employees, a figure ' year exposure duration with that for a employees, particularly those employed more than 5 times the Supreme Court's . 20-year exposure duration. Although by asbestos abatement and demolition guidelines for significant risk. Therefore, there is a 56 percent reduction in exposure duration, there is only a 31 contractors, who have regular exposures OSHA does not agree with that its risk to asbestos. Second, as discussed above, estimates are significantly overstated percent reduction in total asbestos- OSHA's determination of the because they do not differentiate among related cancer risk (from 64 to 44 deaths significance of risk must be based on the fibers of different types. per 1,000 employees). Accordingly, risks that would be permitted by a A controversial issue.raised during assuming that employees are exposed to standard, and not the actual risk of the rulemaking was whether the asbestos for shorter durations because employees who are exposed at a level combined impact of smoking and of employee turnover would actually below that standard. OSHA has no asbestos exposure on the incidence of . increase the absolute risk among the basis for believing that risks posed by asbestos-related disease should lead larger number of workers exposed for exposure to asbestos at the current PEL , OSHA to promulgate regulations less than their working lifetimes; of 2 f/cc in construction would be any prohibiting smoking in workplaces iti GLEASON-000897