| |||||
|
|
|
|
|
|
| |||||
|
|
|
|||
| |||||
     |
 |
|
 June 28, 2001 Lisa M. Brosseau, Sc.D, CIH Re: Comments on the Proposed Changes to the ACGIH Oil Mist - Mineral TLV Dear Dr. Brosseau: The Society of the Plastics Industry, Inc. (SPI) appreciates this opportunity to comment on the Threshold Limit Value (TLV) recommended for mineral oils mists by the ACGIH Chemical Substances Committee in January, 2001. Founded in 1937, The Society of the Plastics Industry, Inc. is the trade association representing one of the largest manufacturing industries in the United States. SPI's approximately 1,500 members represent the entire plastics industry supply chain, including processors, machinery and equipment manufacturers and raw material suppliers. The U.S. plastics industry employs 1.5 million workers and provides $304 billion in annual shipments. For more information visit SPI on the Web at www.plasticsindustry.org. SPI has reviewed ACGIH's recommendations regarding mineral oil mist standards and has two concerns. First, we do not believe it is appropriate to classify all mineral oils mists, regardless of their degree of refinement, as A2 (suspected human) carcinogens. Second, the proposed reduction of the TLV to 0.2 mg/m3 is not supported by the scientific evidence on which it is based. Accordingly, SPI respectfully requests that ACGIH reopen this recommendation to consider the following: 1) retaining the current classification and TLV for highly refined mineral oils; 2) applying the A2 carcinogen classification to those unrefined and mildly refined mineral oils containing significant levels of polynuclear aromatic hydrocarbons (PAHs); and 3) retaining the current TLV for those mineral oils appropriately reclassified as A2 carcinogens until ACGIH develops a scientifically sound basis for any change. Background In general, the ACGIH TLVs are widely relied upon, cited and used both inside and outside the United States in a variety of contexts. Despite the ACGIH "Policy Statement on the Uses of TLVs and BEIs", the TLVs are frequently viewed as de facto regulatory standards, or the appropriate standard of care under tort law. Accordingly, we believe the time has come for ACGIH to incorporate two fundamental principles into the TLV development process on a prospective basis. First, TLVs should be adopted through the consensus process, which is based on the principles of openness and due process. Second, chemical classifications and TLVs should be developed and applied only to the extent necessary to control a recognized, significant risk. Chemical classifications and TLVs should not be employed with the objective of eliminating a speculative or hypothetical risk. The Classification Issue The proposed standard does not distinguish between mineral oils mists and their additives or between highly refined "pure" mineral oil mist and mist derived from products containing synthetic fluids. Instead, the ACGIH proposes one standard for all mineral oil mists, regardless of formulation. As a result, the proposed A2 classification does not reflect the differences in the potential health risks posed by different types of mineral oils. For example, the grouping of all mineral oil mists into one category does not take into account the part that polynuclear aromatic hydrocarbons (PAHs) play in the carcinogenic effects of mineral oil mists. One of the very studies relied upon by ACGIH to support its determination that all mineral oil mists should be designated possible human carcinogens has shown that the contamination of oils by PAHs is a determining factor in the carcinogenic effect of the oils1. Variations between study results indicate a need to further examine other relevant variables prior to grouping all mineral oil mists in one A2 carcinogen category. In a large number of the studies cited, either the observed increase in cancer rates was not statistically significant or no conclusion was made concerning the observed cancer rates; there was a high degree of variation in the observed cancer sites (i.e., studies either focused on a specific cancer, such as sinonasal or on a broad cancer morbidity pattern); contradictory results appeared in other studies (i.e., less than the expected number of cancer cases among the exposed group); and only one study (Ely, 1970) reported actual mineral oil mist concentrations. Further, based on the summaries of the studies provided in the Background Documentation (p. 6, col. 2 through p. 10, col. 1), the chemical composition of the mineral oil mist was often either not known or the exposure was to a variety of different mineral oils, making comparison among studies questionable. The Background Documentation (p. 10, col. 2) for this proposal states that "in all cases, confounding by contamination … has not adequately been eliminated." It goes on to say that mineral oil products manufactured using severe hydrotreatment "contain very low concentrations of PAHs and have been shown to be noncarcinogenic .…" Nevertheless, an A2 Carcinogen classification is proposed for all mineral oil mists because "the increased odds ratio for larynx cancer reported by [one study] may be the result of [other characteristics of the mineral oil] rather than contamination by PAHs [emphasis added]." We do not believe TLV classifications should be established on the basis of such a speculative hypothesis. ACGIH clearly acknowledges that the greater the contamination levels of oils the greater the oil's carcinogenic potential. As noted by AGCIH, the International Agency for Research on Cancer (IARC, 1984) concluded that while there is sufficient evidence for the carcinogenicity of untreated and mildly treated oils in humans, there is inadequate evidence for highly-refined oils. Although the refining process removes such contaminates and severely refined oils are virtually free of contaminates, ACGIH did not take the degree of refinement of an oil into account in determining the appropriate TLV. In other words, without explanation, the ACGIH proposal does not appear to consider this critical IARC determination. The ACGIH proposal is also in conflict with the approach taken by the U.S. Food and Drug Administration (FDA) in regulating the use of mineral oil in foods. FDA has established an ultraviolet absorbance limit for mineral oil to determine whether it contains an excessive level of PAHs. Mineral oils which satisfy the test may be used as direct food ingredients (21 CFR § 172.878) and as components of food packaging (21 CFR § 178.3620). We do not believe it would be responsible for ACGIH to classify these FDA-cleared food ingredients as carcinogens. The TLV Issue The proposed TLV of 0.2 mg/m3 does not reflect the differences in health risk potential between different mineral oils. The scientific data cited in support of the A2 classification and TLV change does not clearly indicate that exposure to mineral oil mists resulted in the reported health problems. Although is it clear that mineral oil mists were present in the environments where the studies were performed, workers in these environments also involved exposure to a variety of other contaminants. In all of the cancer studies and in the majority of noncancer studies, researchers were not able to clearly identify, or eliminate, the confounding effects of these other contaminants. Therefore, it is not clear whether the observed heath problems were a result of the mineral oil mist present, or occurred as a result of other factors. Assuming the objective of the ACGIH proposal to lower the TLV is to prevent or decrease cancer risks among workers, there appears to be no supporting evidence that the reduced TLV would have that effect. Although ACGIH cites the Kriebel et. al. study and Greaves et. al. study in support of the 0.2 mg/m3 TLV, neither study clearly indicates that a 0.2 mg/m3 level will significantly mitigate any hazardous effects of the mineral oil mist. For example, the prevalence of asthma in the cited study by Kriebel was 8% among workers with a of 0.19 mg/m3 (geometric mean) as inhalable particulate but was less, 5.8%, among workers exposed at a much higher level of mineral oil mist, 0.78 mg/m3 (geometric mean), in the cited study by Greaves. These contradictory conclusions underscore the difficulty in relating specific adverse effects to exposure to mineral oil mists alone. As noted in the Background Document (p. 3, col. 2), current sampling and analytical procedures involved in the proposed gravimetric measure of inhalable particulate will capture other inhalable particulate material and will thus not allow for a true estimation of total mineral oil mist exposure, therefore confounding the results of any study designed to assess the impact of mineral oil mist on human health. As noted in the Background Document, most studies could not be used to develop a TLV because they did not adequately describe the sampling and analytical methods used. For the remaining three, "the exposure data … are not directly comparable." For two of the three, the differences in the symptom prevalence between the controls and the exposed workers were not statistically significant. For the third, the controls were actually exposed to mineral oil mist at a level that was virtually the same as the exposed group in a study that showed no statistically significant effect from that exposure. Starting with two no-effect studies and one apparently flawed study, we do not believe it is scientifically sound to assert that a no-observed-adverse-effect-level of 0.2 mg/m3 TLV "could be hypothesized" (see p. 10, col. 2 of the Background Document on Mineral Oil Mists) from these studies and then announce that ACGIH will assume the validity of that questionable hypothesis as justification for adopting a TLV of 0.2 mg/m3 . Policy Considerations SPI is very concerned that the proposed standard is based on a speculative hypothesis rather than the scientific data currently available. Instead of advancing workplace safety, this proposed TLV takes away many incentives to test new products for potential carcinogenicity or to develop new less hazardous mineral oil products. It is likely to result in the increased manufacture and use of more hazardous mineral oil products. In other words, classifying all mineral oil products as suspected human carcinogens, when there is strong evidence that low-PAH oils and severely refined oils are not carcinogenic, may dissuade companies from going the extra step (and the extra expense) of further refining. Finally, those manufacturers that take the steps necessary to produce and/or use the low-PAH oils cleared by FDA for use in foods and food packaging will nevertheless be forced to bear all of the burdens associated with the erroneous A2 designation (e.g., loss of sales, unnecessary customer relations issues, unnecessary employee relations issues, unnecessary consumer relations issues) and lowered TLV. * * * * * For the foregoing reasons, SPI strongly urges ACGIH to reopen this recommendation to consider the following: 1) retaining the current classification and TLV for highly refined mineral oils; 2) applying the A2 carcinogen classification to those unrefined and mildly refined mineral oils containing significant levels of polynuclear aromatic hydrocarbons (PAHs); and 3) retaining the current TLV for those mineral oils appropriately reclassified as A2 carcinogens until ACGIH develops a scientifically sound basis for any change. Thank you for your consideration. Sincerely, Susan R. Howe 1. See also, Brooks, T. M. et al. (1995). Mutagenesis, 10(5):409-415. Mineral oils were tested in the Ames Salmonella assay as emulsions in water. The results showed an empirical correlation between increasing mutagenicity and the polycyclic aromatic hydrocarbon content of the oils.
More
Public Policy: Environment
. Worker Safety . Transportation
. Codes and Standards . Food,
Drug,and Cosmetic Packaging . International
Trade
. Other Issues
|
|
|
|
 © Copyright 2003 The Society of the Plastics Industry.
|
|
|
|
|
|
|
      |