Powered by GoogleTranslate
Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Occupational Exposure to Asbestos, Tremolite, Anthophyllite and Actinolite
• Section: 1
• Title: Section 1 - I. Introduction

I. Introduction

This preamble discusses OSHA's decision to remove non-asbestiform tremolite, anthophyllite, and actinolite (herein referred to as ATA and/or non-asbestiform ATA) from the asbestos standards for general industry and construction(29 CFR Sections 1910.1001 and 1926.58). Instead, exposure to non-asbestiform ATA will be regulated by the particulates not otherwise regulated (PNOR) limit in Table Z-1-A of 1910.1000 [15 mg/m(3) (total dust); 5 mg/m(3) (respirable dust)]. Because non-asbestiform ATA is found in combination with other minerals, some of which are regulated by other exposure limits in Table Z-1-A, some employees exposed to non-asbestiform ATA will be protected by those exposure limits as well.

OSHA is also removing and reserving 29 CFR 1910.1101, which was designated "Asbestos" and which has been applied to non-asbestiform ATA during the administrative stay of the revised asbestos standards (29 CFR 1910.100l and 29 CFR 1926.58). OSHA has determined that the 1972 asbestos standard, which had been redesignated 1910.1101, no longer applies to non-asbestiform ATA and thus, there is no current reason to continue to include it in the Code of Federal Regulations.

As discussed further in this preamble, OSHA's determination to remove non-asbestiform ATA from the scope of the asbestos standards, is based on the insufficiency of evidence to support determinations that their further inclusion would protect exposed employees from a risk of disease which was the equivalent in incidence and gravity to asbestos related disease, and that removing coverage would pose a significant risk to exposed employees.

The Agency also finds that the evidence is insufficient to regulate non-asbestiform ATA as presenting a significant health risk to employees other than as a physical irritant, without regard to its analogy to asbestos. Thus no separate standard is necessary at this time and the PNOR limit is appropriate.

In summary the basis for these findings is as follows. Asbestos and non-asbestiform ATA appear to be distinguishable mineral entities on a population basis, and in most instances on a particle basis. The characteristics which differentiate them generally appear to correspond to the properties which may dictate different biologic response. There are mechanistic data from experimental animals exposed to various durable minerals which support counting some particles of non-asbestiform ATA like all asbestos fibers. However, available toxicological and epidemiologic evidence related specifically to non-asbestiform ATA is negative or inconclusive on the issue. Also, in most cases, particles of non-asbestiform ATA appear to be a very small fraction of the dust population to which employees are exposed. Therefore, OSHA finds there is insufficient evidence to support regulating non-asbestiform ATA as presenting a risk similar in kind and extent to asbestos.

Regulating non-asbestiform ATA on its own is also precluded by the limitations of the available evidence. Dose response data concerning non-asbestiform ATA exposure alone is not available; human and animal studies concerning non-asbestiform ATA are individually and collectively, equivocal. Most of the studies do not, on their face report results which show a statistically significant positive response due to non-asbestiform ATA exposure. Criticisms concerning their interpretation mainly concern their power to disprove an association between non-asbestiform ATA exposure and asbestos-related disease. OSHA finds that even if these criticisms are accepted, the totality of evidence still does not constitute affirmative evidence supporting regulating non-asbestiform ATA as presenting a significant health risk.

This rulemaking record therefore is distinguishable from the body of evidence in the EtO rulemaking which was considered "compelling" in the aggregate, although most of the studies were individually flawed. (Public Citizen Health Research Group v. Tyson, 796 F2d 1479). Accordingly, the Agency has determined to not regulate non-asbestiform ATA exposure in a separate standard, since it is unable to conclude, given the information currently available, that it presents a significant risk to exposed employees, at current exposure levels, at any of the asbestos PELs which applied during the history of asbestos standards, or at any other specific level.

OSHA also believes that evidence in this record does not show that removing non-asbestiform ATA from the scope of the asbestos standards will pose a significant risk to exposed employees. As discussed later in this document, testimony and evidence which is not controverted, indicates that, although there is a risk of nonmalignant respiratory disease from high exposures to talc containing non-asbestiform ATA, (See discussion during regulatory alternatives), non-asbestiform ATA is not identified as the causative agent of such nonmalignant disease. OSHA has also determined that there is insufficient health effects evidence linking exposure to non-asbestiform ATA to a heightened risk of cancer. Historic exposure levels of talc containing non-asbestiform ATA (converted from mppcf) linked to production of excess nonmalignant disease have been estimated as approximately 4 to 12 mg/m(3). At levels estimated at approximately 1.5 to 6.5 mg/m(3) (Ex. 84-141, docket H-033c, Kleinfeld et al, at 665; conversion made by ACGIH 1986) excess nonmalignant respiratory disease appears to be eliminated. The current PEL for talc is 2 mg/m(3). (Talc is measured on a gravimetric basis rather by fiber and is thus measure in mg/m(3).) Without inclusion in the asbestos standards, employees exposed to non-asbestiform ATA will be covered by various dust limits in OSHA's Air Contaminant Standards (29 CFR 1910.1000 and 29 CFR 1926.55). Those employees exposed to tremolitic talc, will be covered by the talc standard as well, for that fraction of their exposure which constitutes talc. Where exposure occurs to a mixture of substances the mixture formula in the Air Contaminant Standard applies. Therefore workers exposed to non-asbestiform ATA contaminated talc, the commercial product most likely to contain sizable amounts of non-asbestiform ATA, will be protected by several permissible exposure limits and hazard communication provisions.

The other industries where non-asbestiform ATA exposure occur are those where ATA are constituents of crushed rock and stone. At the time of the proposal, OSHA's contractor reported the following conclusions about the potential for exposure to non-asbestiform ATA in industries which consume crushed stone, sand, and gravel. "The occurrence of non-asbestiform tremolite, actinolite, and/or anthophyllite is erratic and unpredictable. However, when it does occur - even in significant quantities - it does not appear that construction or other activities which disrupt the minerals and produce dust result in airborne fiber levels which exceed OSHA's action level of 0.1 f/cc. "(CONSAD report, Ex. 465 at 1.14). (In this example, particles of non-asbestiform ATA, which are greater than 5 microns in length and have aspect ratios greater than or equal to 3:1, are measured as "fibers/cc" as opposed to the example above where dust was measured on a gravimetric basis.) No evidence was presented in the rulemaking which showed that workers will be exposed to airborne levels of non-asbestiform ATA during activities involving crushed rock or stone which significantly exceed CONSAD's estimate. Therefore, OSHA concludes that removing these workers from the protection of the asbestos standard will not result in a significant health risk to them because, even if workers were exposed to levels estimated by OSHA's contractor, there would likely be no significant risk.

The Agency acknowledges that certain public health organizations have recommended that OSHA continue to regulate non-asbestiform ATA under the asbestos standards. Thus, the American Thoracic Society (ATS) concluded that "(a)t present, the prudent public health policy course is to regard appropriately sized (non-asbestiform) tremolite "fibers" in sufficient exposure dose (concentration and duration), as capable of producing the recognized asbestos - related diseases, and they should be regulated accordingly. (Ex. 525 at 15). As discussed in detail in the section on mineralogy, OSHA continues to believe that fiber dimension is the most significant indicator of fiber pathology. However, there is insufficient evidence in the record to determine the parameters of "appropriately sized" tremolite particles. In addition the evidence which is available more likely associates fibers with dimensions common to asbestos populations with disease causing potential than particles found in non-asbestiform ATA populations. For example, the Stanton index particle of at least 8 um in length and less than .25 um in width, is rarely associated with non-asbestiform ATA particles, but is a common dimension for asbestos fibers.

NIOSH also recommends that OSHA continue to regulate non-asbestiform ATA under the asbestos standards. Its major rationale is similar to the ATS's, i.e. "NIOSH concludes for regulatory purposes that cleavage fragments of the appropriate aspect ratio and length from the non-asbestiform minerals should be considered as hazardous as fibers from the asbestiform minerals." (Tr. 5/9, p. 9) As stated above, OSHA does not believe that the current record provides an evidentiary basis to determine "the appropriate aspect ratio and length", for determining pathogenicity. Even if dimensional cut - offs were known for asbestos fibers, additional data do not support a standard for all ATA minerals based on fiber dimension alone. Available data show that asbestos containing dusts have much greater potency than non-asbestos containing dusts. Nor is there direct evidence showing fiber equivalency for asbestos and non-asbestiform ATA. NIOSH's additional concern is that by deregulating non-asbestiform ATA, OSHA will leave unprotected workers who may be exposed to asbestos, as a contaminant of a non-asbestiform mineral deposit or product to which they are exposed. (See Tr. 5/9, pp. 10-14). In this regard OSHA notes that available evidence indicates that significant contamination of non-asbestiform mineral deposits is identifiable and thus amenable to regulations under applicable asbestos standards.

Thus, OSHA does not believe that potential asbestos contamination of non-asbestos minerals, including non-asbestiform ATA, is sufficient reason to include such non-asbestiform minerals in the asbestos standard. If the presence of asbestos is known, it should be evaluated for extent and exposure potential. The definition of asbestos in the asbestos standards, and the counting criteria therein are sufficiently broad so as cover all identifiable asbestos fibers. As discussed later in this document, OSHA has not changed these provisions. If an identification error is made, it is likely to be a false positive for asbestos rather than a false negative. Airborne exposure data in the record relating to naturally occurring asbestos as a contaminant, show that exposure potential is likely to be very low, even where asbestos is a major contaminant. (CONSAD study, Ex. 465) Also, answering NIOSH's concerns, evidence in the record shows that differential analysis of mineral deposits and products can and is being performed using a variety of methods. (See Langer, Tr. 5/11, pp. 225-227). Based on these considerations, OSHA does not believe that including non-asbestiform ATA in the asbestos standards in order to insure that asbestos contamination of non-asbestiform ATA deposits will not be ignored is necessary to protect employees exposed to mineral products where asbestos contamination is a possibility. In consequence of this decision ATA will be regulated as a PNOR at 5 mg/m(3) or 15 mg/m(3) because of physical irritation. Because a mixture of talc and non-asbestiform ATA has been shown to cause nonmalignant respiratory disease, the mixture formula clearly is applicable.

Paperwork Reduction

In accordance with the Paperwork Reduction Act of 1980 (44 U.S.C. et. seq.), and the regulations issued pursuant thereto (5 CFR part 1320), OSHA is required to submit the information collection requirements contained in its standards to the Office of Management and Budget (OMB) for review under section 3504 (h) of the Act. However, in this final there are no information collection requirements.


This document has been reviewed in accordance with Executive Order 12612, 52 FR 41685 (October 30, 1987), regarding Federalism. This Order requires that agencies, to the extent possible, refrain from limiting state policy options, consult with States prior to taking any actions that would restrict actions only when there is a clear Congressional intent for the agency to do so. Any such preemption is to be limited to the extent possible.

Section 18 of the Occupational Safety and Health Act (OSH Act), expresses Congress' clear intent to preempt State laws with respect to which Federal OSHA has promulgated occupational safety or health standards. Under the OSH Act a State can avoid preemption only if it submits, and obtains Federal approval of a plan for the development of such standards and their enforcement. Occupational safety and health standards developed by such Plan - States must, among other things, be at least as effective as the Federal standards in providing safe and healthful employment and places of employment.

To the extent that there are any State or regional peculiarities, States with occupational safety and health plans approved under Section 18 of the OSH Act would be able to develop their own State standards to deal with any special problems.

Those States which have elected to participate under Section 18 of the OSH Act would not be preempted by this final standard and would be able to deal with special, local conditions within the framework provided by this standard while ensuring that their standards are at least as effective as the Federal standard.

State Plans

The 23 States and 2 territories with their own OSHA - approved occupational safety and health plans must adopt a comparable standard (i.e. a standard which is at least as effective as the federal standard) within 6 months after the publication of a final standard for occupational exposure to non-asbestiform ATA or amend their existing standard if it is not "at least as effective" as the final federal standard. States with their own OSHA - approved occupational safety and health plans may also elect to be more protective than the federal standard. The states and territories with occupational safety and health state plans are Alaska, Arizona, California, Connecticut, Hawaii, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Nevada, New Mexico, New York, North Carolina, Oregon, Puerto Rico, South Carolina, Tennessee, Utah, Vermont, Virginia, the Virgin Islands, Washington, and Wyoming. (In Connecticut and New York, the plan covers only State and local government employees.)

[57 FR 24310, June 8, 1992]

Regulations (Preambles to Final Rules) - Table of Contents

Thank You for Visiting Our Website

You are exiting the Department of Labor's Web server.

The Department of Labor does not endorse, takes no responsibility for, and exercises no control over the linked organization or its views, or contents, nor does it vouch for the accuracy or accessibility of the information contained on the destination server. The Department of Labor also cannot authorize the use of copyrighted materials contained in linked Web sites. Users must request such authorization from the sponsor of the linked Web site. Thank you for visiting our site. Please click the button below to continue.