=======================Electronic Edition========================
RACHEL’S ENVIRONMENT & HEALTH WEEKLY #416
—November 17, 1994—
News and resources for environmental justice.
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THE SCIENTIFIC BASIS OF CHEMICAL SAFETY–PART 2:
STANDARDS THAT KILL
As we saw last week, Threshold Limit Values (TLVs) are air
pollution limits for the workplace. Since 1946, TLVs have been
devised and published by a private organization called the
American Conference of Governmental Industrial Hygienists
(ACGIH), a private group composed of industrial hygienists from
state and local governments, plus academics and industry
consultants. ACGIH clearly wants its audience to believe that
TLVs are health-based standards; the preface to ACGIH’s annual
TLV list says TLVs “are health-based recommendations derived from
assessment of the available published scientific information from
studies in exposed humans and from studies in experimental
animals.” Furthermore the preface to the annual TLV list says
TLVs are airborne concentrations “to which nearly all workers may
be exposed for 8 hours per day, 40 hours per week for a working
lifetime without adverse effect.” [1]
In 1970 Congress created the Occupational Safety and Health
Administration (OSHA) to protect workers from injury and from
toxic chemicals. In 1971, OSHA adopted the ACGIH’s 1968 TLVs as
official workplace standards called PELs (permissible exposure
limits). The rationale at the time was that the Occupational
Safety and Health Act (OSH Act) required OSHA to adopt standards
quickly and there was no time to develop independent standards.
However, the OSH Act created a new process for OSHA to follow in
establishing future PELs, and it created a National Institute for
Occupational Safety and Health (NIOSH) with official
responsibility for providing scientific advice to OSHA. During
the next 20 years, NIOSH developed and published Recommended
Exposure Limits, or RELs, for 160 chemicals. However, OSHA
ignored the bulk of NIOSH’s recommendations and adopted only 12
new PELs during the 20-year period.
During the 20 years that OSHA spent setting 12 new PELs, the
ACGIH TLV Committee revised 234 TLVs downward, making them more
protective (and stricter than the corresponding PELs which had
been adopted in 1970 but never revised), and adopted 168 new TLVs
for which there were no PELs. By 1987, official PELs were lagging
badly behind the development in TLVs, and this was a source of
embarrassment to OSHA. In the spring of 1987 OSHA began a formal
procedure to adopt a new Air Contaminants Standard. OSHA
proposed to adopt, once again, all of the ACGIH’s TLVs (in their
1987 revision). [2]
During the next 2 years, TLVs came under close scrutiny. In 1988,
two occupational hygienists, Barry Castleman and Grace Ziem,
examined the official documentation that ACGIH said it had relied
upon in setting TLVs. (See RHWN #128.) Castleman and Ziem
reported that at least 104 of the TLVs were based on nothing more
than unpublished allegations, often made to the TLV committee by
industry scientists whose employers had a direct financial
interest in the particular substance being considered. [3]
Despite this information, OSHA continued proposing to adopt all
TLVs as official PELs.
During public hearings on the proposed Air Contaminants Standard
in 1988, NIOSH placed 4000 pages of testimony in the record.
They offered evidence that at least 98 of the 400 proposed PELS
would not protect the health of workers. For 50 of the 98
substances, NIOSH had already published Recommended Exposure
Limits (RELs). NIOSH’s average (mean) REL was 71 times lower
(more protective) than the corresponding TLV.
During the public hearings, the New Jersey State Department of
Health (NJSDOH) placed in the record a study that it had
conducted of existing and proposed PELs, using EPA’s [U.S.
Environmental Protection Agency’s] Integrated Risk Information
System (IRIS) database. [4]
The IRIS database was created by EPA to collect and
systematically review human and animal toxicity data on
particular chemicals. The IRIS database in 1990 contained
reviews of 370 chemicals. The purpose of the IRIS system is to
support EPA and other governmental regulators in their efforts to
protect public health.
NJSDOH researchers randomly selected 43 existing and proposed
PELs. Using widely-accepted risk assessment methods to
extrapolate from reference doses and unit risks in the IRIS
database, the NJSDOH researchers calculated health-based
occupational guidelines. For the 43 chemicals, the average
(mean) existing PEL was 9.5 mg/m**3; the average (mean) proposed
PEL was 7.5 mg/m**3; and the average (mean) health-based
guideline calculated by NJSDOH was 0.004 mg/m**3. Thus average
existing PELs exceeded NJSDOH’s health-based guidelines by a
factor of 2375 and proposed PELs exceeded NJSDOH’s health-based
guidelines by a factor of 1875, on average. The New Jersey State
Department of Health concluded that OSHA’s proposed PELs were
based on outdated information and weak methodology and would not
protect worker health.
Despite these compelling criticisms, OSHA formally adopted all of
ACGIH’s TLVs as enforceable PELs in January 1989. As a practical
matter, this astonishing decision had the effect of making
ACGIH’s TLV Committee the de facto workplace-standards-setting
body in the U.S. Since the TLV Committee operates behind closed
doors without peer review of its methods or conclusions, this
transfer of authority from OSHA to ACGIH effectively gutted the
OSH Act, which had established a public process for setting
occupational standards. (In July 1992, a court declared the new
PELs illegal, thus re-establishing the 1971 PELs, based on the
1968 TLVs, as official U.S. standards; the Clinton administration
did not appeal that court ruling. [5])
Now, as we saw last week, the TLVs themselves have been subjected
to withering criticism. Although they are called THRESHOLD limit
values, implying that they are set at a level that would PREVENT
disease, in many cases they have been set at or above levels at
which disease is known to occur in humans.
For example, 7 of 14 workers exposed to chlorodiphenyl at 10% of
the TLV suffered chloracne; 10 out of 10 volunteers exposed to
ethyl ether suffered upper respiratory tract irritation at 75% of
the TLV; and 5 out of 5 volunteers exposed to 2-nitropropane
suffered central nervous system effects such as headaches,
nausea, and vomiting at 80% to 180% of the TLV. In the Air
Contaminants Standard, OSHA set the PEL for these three
substances at the same level as the TLV. [6]
Today the ACGIH and its TLVs are being subjected to a continuous
stream of criticism from knowledgeable authorities. For example,
a well-known industrial hygienist in New Jersey recently said,
“The reality is that for the vast majority of chemicals, we have
little or no chronic toxicity data. Even when we do, we usually
don’t know the chemical’s effects on lung function, nervous
system function, immune or endocrine system function,
reproductive function, or other vital bodily functions. Without
such data, claims that we know what exposures are permissible and
will not harm workers are false.
“They [ACGIH] still have not acted rigorously to avoid conflicts
of interest among members, however. Instead of requiring
disclosure of corporate consulting relationships, they are using
an honor system where members merely state upon appointment that
they have no conflicts of interest. While some positive changes
have been made, they do nothing to undo the damage already done
by the present TLVs which were set under the old, dysfunctional
system, and the changes do not go far enough to ensure that past
mistakes will not be repeated.
“Exposure limits are theoretically helpful to workers. However,
if we don’t get the numbers right, and it looks like ACGIH and
OSHA usually have not, then they are harmful.” [4]
In 1993, a researcher recalled a 1956 criticism of TLVs: “In the
introduction to its 1956 list… the Committee on Threshold
Limits says, ‘Values are given… for the maximum average
atmospheric concentrations of contaminants to which workers may
be exposed… without injury to health.’ Careful study of the
data which support the currently accepted values suggests that no
such description can be truthfully attached to most of them.” [7]
[The … appear in the 1993 original.]
A July 1994 analysis of TLVs finds that 229 of the approximately
600 current TLVs have been criticized, in one technical forum or
another, as inadequate to protect workers’ health. [8]
What then is the purpose of TLVs, if not to protect the health of
workers?
In 1935, a group of industrialists met to devise a comprehensive
response to the “industrial dust problem.” At that time,
lawsuits were pending, demanding hundreds of millions of dollars
in damages for occupational lung disease. This meeting led to
the formation of the Air Hygiene Foundation in 1936, with 200
corporations and trade associations as members. One goal of the
Foundation was to set up “authoritative and approved standards
for the control of industrial dusts which, if complied with by
industries, or by industrial companies, will act as a defense
against personal injury suits.” [8]
Though TLVs often may not protect the health of workers, they do
provide what is now commonly known as the “TLV defense” when a
company is sued for harming workers by exposing them to toxic
chemicals. The typical TLV defense quotes the ACGIH saying TLVs
are “thought to be safe for workers –based on the best available
information.” The winners in this sad affair are the business
interests and lawyers who use the TLV defense as a shield from
liability in personal injury lawsuits. The losers are the 50,000
to 70,000 workers who die each year from diseases they developed
after exposure on the job, and the estimated 350,000 workers who
develop new cases of occupational disease each year from toxic
exposures.
                
                
                
                
    
–Peter Montague
===============
[1] TLV documents quoted in Ernest Mastromatteo, “TLVs: Changes
in Philosophy,” APPLIED INDUSTRIAL HYGIENE Vol. 3, No.3 (March
1988), pgs. F12-F16. In 1988, Mastromatteo was head of ACGIH’s
TLV Committee.
Descriptor terms: occupational safety and health; osha; job
safety; worker safety; tlvs; threshold limit values; acgih;
american conference of governmental industrial hygienists;
congress; niosh; barry castleman; grace ziem; pels; rels;
permissible exposure limits; new jersey state department of
health; njsdoh; iris database; risk assessment; epa;
chlorodiphenyl; ethyl ether; 2-nitropropane; air contaminants
standard; air hygiene foundation; tlv defense; lawsuits;
morbidity statistics; mortality statistics; eileen tarlau;