Document Lg6v5751d3GdXjEaL3nBRyjvw

Federal Register / Vol. 51, No. 119 / Friday, June 20, 1986 / Rules and Regulations 22619 and duration of exposure, the exposures authors calculated standardized Henderson and Enterline (Ex. 84-48), have been recent and of limited mortality odds ratios (SMOR) using Flnkelstein (Ex. 84-240), and Seidman et duration. The full manifestation of the arteriosclerotic heart disease as a al. (Exs. 84-87, 261-A). In addition, a effects of shipyard employment would referent to offset some of the potential number of studies have recorded cases not yet be expected to be present in this biases in PMRs. The calculated SMORs of mesothelioma among members of the group" (Ex. 162-C, p. 1). were reported to be virtually identical to families of asbestos workers (Anderson In comparison with the mortality the PMRs, indicating the absence of any et al,, Exs. 84-16, 84-17; Vianna and observed .in white males in Connecticut, significant biases In the PMR's for Polon, Ex. 84-186); Li et al., Ex. 84-149). the overall mortality for the cohort with cancer. The authors concluded that this Mesothelioma has also been observed 11.5 years of exposure was significantly study, with an overall pattern of among community members living near (p less than 0.05) elevated (356 observed, observed mortality consistent with that asbestos mines and factors (Wagner et 316 deaths expected). Mortality from found in other populations exposed to al.. Ex. 2-21; Newhouse and Thompson, cancer at all sites was also in excess (90 asbestos, "strongly suggests the Ex-84-70). For example, in 1978, observed, 80 expected). The major sites presence of significant asbestos-related Anderson et al. (Ex. 84-16) reported that of cancer increase were the lung (35 illness is (sic] a population with 4 cases of pleural mesothelioma had observed, 26 expected) and the 'secondary' asbestos exposure" (Ex. been diagnosed among 626 family gastrointestinal tract (19 observed, 15 expected), two cancer sitcs.known to be related to asbestos exposure. These excesses were seen in both production and support workers, whereas office employees from the some shipyards experienced mortality similar to that of the general male population of Connecticut. Finding such excesses in a cohort that had relatively short employment and that had been followed for a relatively short period of time was. in the authors' words, "unexpected" and leads to augmented concern for the next two or three decades" (Ex. 162-C. pp. 3. 4). The study (Ex. 182-C) provides additional qualitative evidence of the excess risk of lung cancer mortality and GI cancer mortality experienced by asbestos-exposed workers. Although these investigators were surprised to rind such excesses following relatively 163-E. p. 11). The interpretation of these results is limited by the design of proportionate mortality studies. Although the investigators reported that half of the local union members were employed in installations of metal ducts, and thus were must likely to be exposed intermittently to asbestos, it is not known what proportion of the deceased members were so employed. Moreover, although the observed deaths occurred in a predominantly metropolitan population, the expected distribution of deaths was based on general U.S. mortality rates; the resultant comparison is not ideal because of the generally recognized differences In mortality patterns of urban populations in comparison to those of the overall U.S. population. These Investigators did strengthen their study results by . calculating SMORs. contacts of amosite factory workers. Presumably, family contacts received their exposure to asbestos from dust carried home on the worker's clothing, and especially during the laundering of dusty clothes. Although exposure measurements were not taken for family . contacts, OSHA considers it very likely that their cumulative exposure was less than the cumulative exposure that would result from lifetime exposure to the 2 f/cc standard. OSHA believes that these findings, as well as the observation in epidemiological studies of excess mortality resulting from low cumulative exposures to asbestos, further support the Agency's Finding from the risk assessment that the 2 f/cc PEL is inadequate for protecting worker! against the risk from lung cancer and mesothelioma. 3. Experimental Evidence recent asbestos exposure, other authors (Ex. 306-B, Ex. 320) have noted that significant increases in the lung cancer death rate begin to appear 10 to 14 years 2. Evidence of an Excess Risk of Lung Cancer and Mesothelioma at Low Cumulative Exposures of AsbeBtos after the First exposure and peaks In establishing whether an existing between 30 and 35 years after (Ex. 306- permissible exposure limit is inadequate B, p. 57). . for protecting workers against the risk of Zoloth and Michaels (Ex. 163-E) occupational disease, the Agency relies performed a proportionate mortality principally on the Findings of analysis of 381 deaths that occurred, quantitative risk assessments and an among white males who had been evaluation of the significance of the risk members of a local New York chapter of presented by exposure at the existing the Sheet Metalworkers International ' PEL After conducting the quantitative Association for at least 10 years. risk assessment for asbestos, OSHA Spe'cific.estimates of asbestos exposure concludes that the 2-f/cc PEL is . levels were not given; however,. inadequate for worker protection and exposure was described as being that reduction of the PEL is warranted intermittent and incidental. Half of the (see Section V, Quantitative Risk local union members were employed in Assessment, sind Section VI. Several animal studies are contained in the record that show that experimental animals, when administered asbestos fiber by inhalation, injection, or implantation, develop malignant tumors at a rate higher than unexposed animals (Exs. 84338; 84-320; 84-205; 94-96; 84-197; 84120; 84-128; 84-240; 84-193; 84-195). No rulemaking participant questioned the causal relationship between asbestog exposure and the development of malignancies in experimental animals. OSHA believes that, while these studies in general support the findings of epidemiology studies, they are more germaine to the issues brought up during the rulemaking regarding the installation of metal ducts. The. expected Significance of Risk). OSHA's finding distribution of deaths was based on U.S. that the 2 f/cc PEL is inadequate is relationship between fiber type and dimension and the carcinogenicity of white male mortality rates, with supported by the observations of excess asbestos. OSHA discusses these adjustments for age and date of death. cancer mortality among workers who . experimental studies in a later section There was significant (p less than have been exposed to cumulative levels that deals with the issues of fiber type 0.05) excess mortality from all cancers of asbestos lower than would be and size. . (PMR-152), lung cancer (PMR-160), colo permitted by lifetime exposure to 2 f/cc. rectal cancer (PMR-232). and non- These observations, first referred to in Hodgkins lymphoma (PMR-236). In the November proposal and discussed 4. Summary of the Evidence of Lung Cancer and Mesothelioma addition, three deaths from above, were derived from the studies by After reviewing the studies discussed mesotheloma were observed. The Dement et al. (Exs. 84-36; B4-37), above, OSHA finds that the evidence foi GLEASON-000867