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OCR for page 69
69
ASBESTOS
Part II: Occupational Safety and Health
Agency/National Ins~i tute for
Occupational Safety and Health
A. BACKGROUND AND CONTEXT
le Describe the chemical and its usese
Asbestos is a general term for a group of naturally occurring
hydrated mineral silicates that separate into fibers. Asbestos
minerals used commercially include chrysotile, amosite,
croc idol ite, tremor ite 9 ac t ino lite, and anthophyl 1 i te ashes tos .
Since asbestos is highly resistant to heat, has high tensile
strength, and moderate to good chemical resistance, it has many
uses. These include asbestos-cement pipe, asbestos paper,
friction products, vinyI-asbestos floor tile, paints, coatings and
sealants, and gaskets and packings.
2. Describe how the question of risk was elevated to the agency
leve 1.
By the late 1960s, extensive scienti f ic documen tat ion 1 ead to
widespread awareness and concern regarding the dangers of asbestos
to workers . The Qrganizat ion o f Chemica 1 and Atomic Workers
(OCAW) union was publicly critical of what it perceived as
flagrant industry violations of good incus trial hygiene practices,
as indicated by the American Conference of Governmental and
Industrial Hygienists standard of 12 fibers/cc.
The asbestos issue had clearly come into the political
limelight by 1970. During congressional discussions of the
Occupational Safety and Health (OSlI) Act, asbestos was highlighted
on both floors of Congress as a primary example o f the kind of
hazardous exposure from which workers needed protection.
OCR for page 70
70
Asbestos was included in the initial promulgation o f
Occupational Safety and Health Administration (OSHA) standards on
May 29, 1971, a month after the agency came into existence. At
that tire, an exposure limit was set at 12 fibers per cc or 2
million particles per cubic foot of air. A. petition for an
emergency temporary s tankard to control concentrations of asbestos
dus t at more stringent levels was submitted to the Secretary of
Labor by the Industrial Union Department (luff) of the AFI`/CIO on
November 5, 1971. As a result of that petition, an emergency
temporary standard of 5 fibers per cc of air was published by OSAKA
on December 7, l9JI. This was followed on January 12, 1972, by
OSHA's publication in the Federal Register of a "notice of
proposed rulemaking" ~ NPPM) for a permanent standard of 5 fibers
per cc.
On January 24, 1972, OSHA established an Advisory Committee on
Asbestos Dust and charged its members to make recommendations with
regard to the proposed standard. A criteria document on asbestos,
which contained recommendations for a permanent asbestos standard,
was submitted by the National Institute for Occupational Safety
and Health (NIOSH) to OSHA on February I, 1972. NIOSH recommended
a 2 fiber per cc permissible level of exposure, to become effec-
tive two years after promulgation of a permanent standard. On
February 25, 19729 OSHA's Advisory Committee on Asbestos Dust, by
narrow margins endorsed the NIOSTI recorma-endation~. OSHA held
public hearings during the period March 14-17, 1972, to receive
data, views a and arguments from interested parties concerning the
proposed asbestos standard. A "permanent" s tandard for occupa-
tional exposure to ashes tos dus t was published in the Federal
Register on June 7, 1972. The regulation es tablislled a permis-
sible occupational exposure level of 5 fibers ~ longer than 5
micrometers) per cc of air, which was to be lowered to 2 fibers
per cc after four years.
Less than two months after promulgation of the s tandard, the
BUD of the AFL/CID, along with other unions, filed suit (July 28,
1972) in the U. S a Court of Appeals challenging the regulation.
Among other allegations, it charged that OSHA's decision to delay
implementation of the two-fiber exposure limit for four years
(unti 1 July 1, 1976 ~ violated "highes ~ degree of health
protection" under section 6(b) (5) of the OSH Act.
On April 15, 1974, a three-judge panel in the U.S. Court of
Appeals for the District of Columbia ruled in the case, in effect,
denying the IUD petition but ordered OSHA to:
~ Review the 1976 implementation date for the two-fiber
exposure level requirement, suggesting that OSHA might require
the two-fiber level In those sectors of the industry where it
was already feasible to achieve; and
OCR for page 71
71
Provide ~ longer period for the retention of personal and
environmental monitoring records. (The standard, as pro-
mulgated, provided for a three-year retention period. ~
In response to the court-remanded issues, OS'dA elected to
initiate rulemaking. As indicated in the October 9, 1975 Federal
Register notice:
It is OSHA's belief that the record of the 1972 asbestos
standard proceeding is inadequate to properly resolve the
the two issues raised by the court's remand and that in
the interest of achieving the best feasible occupational
Wealth protect ion a new rulemaking proceeding should be
initiated so that fresh and more detailed evidence may be
developed regarding changes in industrial usage, compliance
capabilities, and employee health practices which have oc-
cured since the Standard 's promulgation over three years ago.
In not taking any action earlier and then deciding to initiate
a new rulemalcing, OSHA effectively prohibited application of the
two-fiber standard prior to July 1, 1976.
lrhe NPRM went beyond the court-remanded issues and addressed
several others. In addition, it called for Lowering the standard
of exposure to 0.5 fibers/cc with a ceiling of 5 fibers/cc for any
period not exceeding 15 minutes. There was no discussion of when
or if the proposed 0. 5-fiber standard would be feasible.
Closing date for comments on the 1975 proposal was extended
twice and ended up at April 9, 1976. In the meantime, on December
1, 1975, OSHA requested that NIOSH reevaluate the health effects
data on asbestos. A revised criteria document '~as prepared and
completed in December, 1976. The NIOSH recommendation stated that
the asbestos standard should "be set at the lowest level
detectable by available analytical techniques. " NIOSH defined
this level as 0.1 fibers per cc.
As far as could be determined, no further action was ever
taken on the 1975 NPRM. Hearings were never held.
3. Under what statutes and agency jurisdiction does the chemical
fall? That statutory tes ts governed the decis ion?
The chemical falls under the jurisdiction of the Occupational
Safety and Health Act of 1970. The t2 fibers/cc standard was
promulgated under Section 6( a) as a "consensus s tandard" not
requiring any rulemaking . The "emergency temporary s randard" 0 f
fibers/cc was promulgated without rulemaking under Section 6( c) .
The "permanent standard" of 5 fibers/cc ~ lowered to 2 fibers/cc
after four years) was promulgated under Section 6~. Rulemaking
is required for permanent standards, and the standard should be
stringent enough to provide total worker protection f or 30 years
of exposure to the extent feasible based on latest information.
Section (20) calls for NIOSH to produce criteria documents with
recommendations that protect the worker for 30 years based on
health cons iderat ions a lone .
OCR for page 72
72
40 What was the decision schedule? Note any statutory or other
action deadlines.
Action
-
Initia1 promulgation of 05aA
12 fibers/Be standard
Emergency temporary ~ tandard
of 5 fibers/cc published as
result of AFL/CID petition
SPRY for "permanent'' 5 fibers/cc
s tandart
NIOSH submits Criteria Document to OSHA
Fina 1 rut emaking f or 5 f ibers / c c
standard which would be lowered
to 2 fibers/cc on July 1, 1976
AFL/CID suit challenging four-year
delay of 2 fiber/cc implementation
Court remand to OSEA to review the
1976 2 fibers/cc implementation date
OSHA initiates new rulemaking (NPRM)
in response to court's remand
NIOSH submits Criteria Document to OSHA
C CRARACTERIZATION OF RISK ro HUMANS
o
(Sections B and C were combined.)
1. What health endpoints were evaluated?
1972 NIOSH Criteria Document
May 29, 1971
Dec. 7, 1971
Jan. 12, 1972
Feb. I, 1972
June 1, 1972
July 2B, 1972
April 15, 1974
Oct. 9, 1975
Dec. 1, 1976
Primary emphasis was on asbestosis, with some consideration of
bronchogenic cancer and mesothelioma .
1976 NIOSH Criteria Document
Emphasis was on mesathelioma, lung and gastrointestinal cancers.
OCR for page 73
73
2. Mat were the key data available for review? (What additional
data were sought? ~
1972 NIOSH Criteria Document
The British Occupational Hygiene Society (BOBS) study of asbes-
tosis incidence in British factories was the chief document used
in the development of the asbestos standard. Numerous epidemio-
togic studies dealing witch lung cancer and mesorhelioma incidence
were also reviewed.
1976 NIOSX Criteria Document
Various epidemiologic studies for lung cancer, cancer of the G.I.
tract, and me~othelioma were evaluated. References are listed on
pp. 88-91 of the document. Also, a paper by Schneiderman ~ 1974)
which critiqued two recent papers (McDonald, 1973, and Enterline
_ al. 1973) was ir~f~luentiat. The two papers in question
supported the idea of a threshold level for asbestos cancer
induction. Schneiderman concluded that these data did not provide
evidence for a threshold or for a "safe" level of exposure.
3. To performed the initial analysis? (What was their back-
grount? Available analytical resources? )
19 72 Criteria Document
The initial analysis was performed by four NIOSH staff
scientists. No data are available on their areas of expertise.
1916 Cri teria Document
The analysis was performed by two staff scientists. One had
training in epidemiology and toxicology. The other was trained in
epidemiology and incus trial hygiene. The latter did the
analytical chemistry analys is in the document.
4. To what extent were results presented quantitatively? What
factors influenced the degree of quanti f ication?
1972 Criteria Document
In the BOHS s tudy, data on 290 ashes tos workers were f itted to
dose-response curve and the conclusion was drawn that an
accumulated exposure of 100 fiber-years/cc (2 fiber~/ce for 50
years) would reduce early clinical signs of asbe~tosis to less
than 12. The NIOSH standard was directly based on this study,
OCR for page 74
74
assuming a 30-year wortclife; i.e., 3 fibers/cc for 30 years.
Introducing a ''measure of prudence" factor to account for car-
cinogenicity, the standard was towered to an average exposure of
2.0 fibers/cc.
1976 Criteria Document
NIOSH concluded that ''evaluation of all available human data
provides no evidence for a threshold or for a 'safe' level of
asbestos exposure O " Consequently, it was decided that the
standard should be set at the lowest level detectable by available
analytical techniques. No quantitative risk assessment was
performed.
5. How was uncertainty described in reaching final inter-
pretations? Were crucial ass~p~ion~ made explicit?
1972 Criteria Document
A cancer "safety factory' was introduced by causing the s tandard to
be reduced from 3 fibersicc to 2 fibers/cc. No Justification was
given for choosing such a factor, and no data on cancer health
risk to workers was estimated based on the new standard.
1976 Criteria Document
Uncertainty was not addressed. By 1976 NIOSH endorsed the non-
threshold theory of cancer. The document states:
There are data that show that the lower the
exposure, the lower the risk of developing cancer.
Excessive cancer risks have been demonstrated at all
fiber concentrations studied to date. Evaluation of
all available human data provides no evidence for a
threshold or for a "cafe" level of asbestos exposure.
5. How were qualitative factors dealt with?
In 1972, there were two schools of thought regarding research
approaches toward the identification and characterization of
ashes tos related di ceases . One school supported an epidemic logic
protocol for determining asbestosis. The other focused on
epidemiologic evidence of cancer. NIOSH gave most weight to the
former approach in 1972. Cancer was considered to be an important
ef fee t, Tut OSHA/NIOSH supported the idea of a threshold value for
cance r .
By 1976, cancer was considered to be the most important and
serious ef feet . NIOSE supported the nonthresho Id theory of cancer a
OCR for page 75
75
7. What qualitative factors affected the weighting of data? Were
such criteria explicit and in accord with anv general guide-
lines?
The question of thresholds was key to the weighting of data ~ see
Q. C . 5 and Q . C .6 ~ . The threshold theory of cancer, maintained by
NIOSH in 1972, was supported by a 1971 National Academy of
Sciences (NAS ~ s tudy which stated that "the appearance of a
gradient or effect suggests that there are levels of inhaled
asbestos without detectable risk. " However, the Surgeon General
of the United States twice ~ in 1968 and 1970) endorsed the
nonthreshold concept for carcinogens.
The nonthreshold theory of cancer, maintained by NIOSH in
1976, was stated as NIOSH policy in May 1975. At that time, Dr.
Fairchild, the Director of NIOSH, quoted the Surgeon General's
1968 statement in order to justify slitting standards for
carcinogens to the lowest feasible level.
8. Describe any internal, internal-advisory, and external
scientific review of the initial analysis. What, if any,
criticism was incurred?
1972 Criteria Document
The initial document was completed by NIOSH s taff with input from
selected outside sources. The document was reviewed externally by
three research scientists and doctors familiar with asbestos-
related diseases. The revised document was then reviewed by
selected representatives of professional societies (e.g., American
Occupational Medicine Association, American Industrial Hygiene
Association). These reviewers were independently appointed by the
societies they represented. The next level of review was an
internal review by the Director of the Institute and other senior
NIOSH s taf f . All comments from previous reviewers were organized
into a table delineat ing which comments had been Hiccup ted and
which rejected. lithe senior committee went over all the comments
and the rationale for responding to them in a particular way.
The ma jor criticism incurred dealt with NIOSH' s focusing on
asbestosis data rather than on the data dealing with cancer.
19 7 6 Cri teria Document
The review process was similar to that of the 1972 document. The
1976 document was based entirely on the premise that there was no
safe level of exposure to asbestos. It has not been determined
whether this position was critized during review. However, as of
May 1975 the nonthreshold theory of cancer had been es tabli~hed
NIOSH pal icy .
OCR for page 76
76
9. How were issues raised in the re~riawks) accommodated?
1972 Criteria Document
cancer "safety factor" was added after a standard was
established Cased on ashestosis data.
1976 Criteria Document
See Q. C O 8
10. Mat other issues arose concerning scientific late and their
use? Br ie f ly de sc ribe di s sent ing opinions
Industry was highly critical of the 1916 document. Representa-
tives s tated that the NIOSH presented no dose-response information
to demons bate that any exposure to ashes tos was unsafe.
11. Is the substance sub jec t deco Pas ~ or possible future regulatory
actions ~ =_
ordinate with other agencies or programs?
Asbestos is subject to possible regulatory action by EPA and
Consumer Product Safety Commission. There was an ashes tos working
group establ ished by flue Interagency Regulatory Liaison Group to
coordinate activities under the Carter Administration, but this
group was disbanded in September 1981.
1) o INTE RPRE'rATION
I. What role did risk as sessment have in the f inal agency document
where standards were established to control the chemical?
The 1972 NIOSlI criteria document played a key role in supporting
the final OSAKA rule establishing a permanent standard of 2
fibers/cc (FR, June 7, 1972) . As described in Q. A. 2, OSHA
endorsed the NIOSH recommendation prior to issuing the rule.
It is hard to determine the role the 1976 NIOSH criteria
document played in supporting ache proposed rule establishing the
00 5-r'iber/cc standard (FR, Oct. 9, 1975) . It was published more
than a year after the proposed OSHA rule and called for an even
more stringent standard (O. 1 fibers/cc). No further action on the
proposed rule was taken.
OCR for page 77
77
2. Were there variations--over tim
ache f ina l ri sk as ses sment?
There were variations over t ice, but there was apparent con-
si~tency across agencies. In 1968 and 1970, the Surgeon General
of the United States stated unequivocally that thresholds for
carcinogens did not exist. In 1972, the NIOSH criteria document
and an EPA rule for national emissions standards recommended or
established exposure levels for asbestos consis tent with a
threshold value for asbestos carcinogenesi~. In flay 1975, Dr.
Fairchild, the Director of HIOSX, quoted the Surgeon General's
1968 statement in order to justify setting standards for
carcinogens to the lowest feasible level. At that time EPA
Interim Guidelines (EPA, 1976, Albert et al. 1971) called for the
use of the linear nonthresho Id dose-response curve. These
variations were significant to the f ina1 risk assessment as
explained in previous questions.
3. To the extent there were issues/concerns about questions of
science would the out come have been improved by coherent
federal guide lines on care inogenic risk assessment,
Federal guidelines could have established the scientific and
policy bases for assessing cancer risk. Much of the confusion
regarding statements about cancer thresholds, the use of data for
asbestosis rather than cancer, and the use of a cancer "safety
factor'' may have been reduced. Implicit assumptions regarding
science and policy ques t ions may have become more evident.
E. PERFORMANCE CONSIDERATIONS
1. Ab ility to obtain relevant scientific information
Senior officials at NIOSH in 1972 stated that cancer studies
published up until 1972 were inconclusive and ambiguous. Air
sampling studies had been performed by different methods which
made intercomparison difficult. In the view of one official there
may have been good unpublished data at that time. However, he
s Pa ted the t NIOSH adhered to a s trio t pa l icy regard ing new
scientific information which may have precluded the use of this
new data. The policy asserted that new information, which had not
yet been published in open literature for public criticism, could
Only be included in the criteria document if i t were peer
reviewed. In the view of this senior official, scientists are
often unwilling to allow such a peer review as it may spoil the
opportunity to have their data published later.
By 1976, the body of information was much more extensive and
readily obtainable.
OCR for page 78
78
2 O Credibility of assessments, 1 ikelihood that interested parties
would accept them as def initive .
.,
For the most part, industry was satisfied with a 5-fiber/cc
standard as proposed by OSHA and as set by ACGTH g ant did not
dwel ~ very much on health arguments. There was disagreement within
industry with the argument that 2 fibers/cc was needed to protect
the heal th o f workers O Some c [aimed that there was no evidence
for hazard at low levels since current and recent incidences of
disease resulted from past exposures at far higher
concentrations. This opinion was given further support in an
industry-sponsored study by McDonald (1973) who claimed to have
evidence that only high exposure caused cancer. By 1975, however,
the 2 f ibers/cc s tandard was widely accepted .
()n the other hand, labor was very dissatisfied with the
proposal of 5 fibers/cc. Mention was made of the fact that the
British Occupational Hygiene Society suggested a level of 2 for
chrysotile but O. 2 for crocidolite which is known to be associated
with mesotheliomaO
The Textile Workers Union wanted a standard that used engine-
ering controls and good handling practices to push toward zero
exposure. The AFL/CID testified in favor of a more s tringer~t
standard than NIOSH had proposed in 1972 which was perceived as
essentially an asbestosis standard. AFL/CID pushed hard for a
cancer standards The 1975 NPRI1 and the 1976 NIOSH criteria
document were more in line with labor's viewpoint.
On February 4, 1976, some 65 representatives from companies
and trade associations representing manufacturers and processors
of asbestos products in the United States participated in a
meeting held in Washington, D.C. They overwhelmingly endorsed
2-fiber level as attainable by application of engineering tech-
nolog~y. However, they stated the proposed O. 5 fiber level was
unnecessary impracticable and lacked medical justifications
What was the extent of diversity of policy orientations
,
represented within the assessment group itself? What was the
degree to which interes e pressures could be exerted from
outside the assessment croup? What was the responsiveness of
_
the assessment to these diverse interes ts?
The group that wrote the 1972 criteria document were all NIOSH
personnel. However, they received input from individuals
representing quite diverse opinions. Dr. Selikoff, who had
prepared a brief for labor for its 1971 petition to OSlIA for an
emergency temporary s tandard, contributed to the initial
document. Industry oriented professions 1 societies g such as the
ACGIH, were intruded to cogent later in the review process. The
incorporation of a cancer safely factor into the standard was
probably in part a response to pressure from labor groups.
OCR for page 79
79
It appears that there was little policy diversity among the
groups that prepared the l9 76 NIOSE document .
4. What were the time and resources necessary to complete the risk
as sessment?
1972 Criteria Document
In the opinion of one of the major architects of the document,
10-15 person years were needed in just the preparation and
review. However, the criteria document covered more areas than a
normal risk assessment. Guidance was given in air sampling
methodology, medical surveillance requirements, labeling,
protective equipment and clothing, and work prac tices .
1976 Criteria Document
In the opinion of one of the authors of the document, perhaps
1-1/ 2 person years were needed to camp le te the document . Th is
document was not as extensive as the 1972 document and basically
dealt with a review of the health effects, sampling methods, and
the proposed s tandard .
5. Responsiveness of assessment agenda to public concerns
. . . ~ ~
Interest group concerns, 2rotesslona. . concerns, and emergence
of new sc lent i f ic informa ~ ion.
~ .
This question has been answered in Questions A
.2, E.2, and E.3.
6. Ability o f the risk assessment to identify research needs .
A consensus of opinion among interviewed NIOSH personnel was that
the risk assessment did s simulate research to some degree, but
that the chemical was of such universal interest that the
influence was probably minor.
7. Extent to which risk assessment impeded or facilitated
regulat ion
The 1979 criteria document probably facilitated regulation by
supporting the premise that there was a safe level of exposure and
calculating what that exposure would be. It is difficult to
determine the impact of the 1976 criteria document, since the
proposed 1975 OSHA rule was not made f inal .
OCR for page 80
80
80 Were related risk assessments consistent?
See Q. I).2.
9. Extent to which there is an explicit distinction between
weight. accorded to scientific factors and policy factors.
Lee asbestos example is a good one to i llu~trate the lack of
distinction That can occur between scientific factors arid policy
factors. In 1972, NIOSH did not accept the premise that any level
of exposure to a carcinogen was unsafe. An NAS study in 1971
supported this conclusion. A contrary opinion was voiced twice by
ache Surgeon General of the United States in 1968 and 1970. He
Stated that since there is no threshold level for a carcinogen,
any level must be deemed to be unsafe. Indeed, OSlIA, in 1971,
referred to the Surgeon General ' ~ statement when promulgating its
consensus standards. There is no documentation as to why NIOSH
chose the NAS view over that of the Surgeon General.
By 1976, NIOSH had changed its position, Treating cancers as
non~hreshold subs tances a In f act, Dr. Fairchi id of NIOSH
justified this position in 1975 by quoting from the 1968 Surgeon
General' ~ statements
lOo Mode and frequency of communication between assessors and
regulators a
There was frequent communication between OSHA and NTOSlI during
promulgation of the asbestos standards. OSHA officials were
invited to peer review meetings, and a record of all review
comments and responses was submitted to OSAKA as part of the
of f ic ial record .
OCR for page 81
81
SOME: IMPORTANT REFERENCE S CITED
Albert, R. E., R. Train, and E. Anderson. 1977. Rationale
developed by EPA for the assessment of care inogenic risks. J.
National Cancer Inst. 58 :1537-1541.
BOBS (British Occupational Hygiene Society). 1970. 1969 Standard
for asbestos dust concentration for use with the asbestos
regulations. Department of Employment and Productivity, Her
Majesty's Factory Inspectorate. Technical Note 13.
Enterline, P. E. and V. Henderson. 1973. Types of asbestos and
respiratory cancer in the asbestos industry. Arch. Environ.
Health 27:312.
EPA (Environmental Protection Agency). 1976. Health risk and economic
impact assessments of suspected carcinogens: interim procedures
ant guidelines. Federal Register 41: 21402-21405.
McDonald, A. I)., 1). Wagner, and G. Eyssen. 1913. Primary malignant
mestothelial tumors in Canada, 1960-1968. Cancer 31:869.
NAS (National Academy of Sciences) . 19 71. Asbe~tos--The need for
and feasibility of air pollution controls.
Schneiderman, M. A. 1974. Digestive sys tem cancer among persons
subjected to occupational inhalation of asbestos particles. A
literature review with emphasis on dose response. Environ. Health
Pers. 9:307.
OCR for page 82
Representative terms from entire chapter:
ashes tos
