Environmental Health Perspectives Volume
103, Supplement 8, November 1995
[Citation
in PubMed]
The Importance of Information Dissemination in the Prevention of Occupational
Cancer
Lawrence J. Fine
National Institute for Occupational Safety and Health, Centers for Disease
Control and Prevention, Department of Health and Human Services, Cincinnati,
Ohio
Abstract
It is assumed that prevention of occupational cancer depends upon dissemination
of research findings, resulting in changes in work processes and reduction
of occupational exposures to carcinogens. Examples of successes and failures
of information dissemination are found in the results of research on silicosis.
Better assessment of the effectiveness of information dissemination is needed,
along with greater understanding of the barriers to implementation of the
information by workers and management and improved hazard surveillance.--
Environ Health Perspect 103(Suppl 8):00-00 (1995)
Key words: occupational cancer, silica, prevention, hazard surveillance
This paper was presented at the President's Cancer Panel
Conference on Avoidable Causes of Cancer held 7-8 April 1994 in Bethesda,
Maryland. Manuscript received: 9 March 1995; manuscript accepted: 24 March
1995.
Address correspondence to Dr. Lawrence J. Fine, National
Institute for Occupational Safety and Health, Centers for Disease Control
and Prevention, Mail Stop R-12, 4676 Columbia Parkway, Cincinnati, OH 45226.
Telephone: (513) 841-4428. Fax: (513) 841-4483.
Abbreviations used: mg/m3, milligrams per meter
cubed; MSHA, Mine Safety and Health Administration; NIOSH, National Institute
for Occupational Safety and Health; NOES, National Occupational Exposure
Survey; OSHA, Occupational Safety and Health Administration; PEL, permissible
exposure limit.
Introduction
In reviewing the relationship between research on occupational cancer
and prevention, it is important to recognize an implicit hypothesis that
underlies the rationale for this research. The hypothesis is that the dissemination
of research results eventually contributes to the initiation of changes
in work processes, which lead to the reduction of occupational exposures
to carcinogens. The process likely involves both the development of new
governmental policies and independent use of this scientific knowledge by
labor and management.
While not a formal proof of the hypothesis of the utility of information
dissemination, a brief summary of some of the major research studies of
silicosis illustrates the successes and failures of the dissemination of
research findings. Exposure to silica has been recognized for a long time
as a cause of occupational lung disease. Increasing in the last 10 years,
it has been recognized as possibly one of the important occupational carcinogens
(1). Workers with silicosis have an approximately 4-fold increased
risk of developing lung cancer (2). The relative risk for lung cancer
in cohorts highly exposed to silica but without silicosis is much lower,
with relative risks of approximately 1.3--still a significant problem given
the large number of currently and formerly exposed workers.
Research conducted in the 1930s in Vermont established that the workers
in granite quarries and sheds had substantial risks of silicosis. Similarly,
in other industries, research was undertaken that found a substantial risk
of silicosis. Shortly afterward, some industries such as the Vermont granite
industry made major changes in work processes to reduce silica exposures
(3). In the 1950s, there was a celebration in the technical and scientific
literature because of a belief that silica exposures were no longer sufficiently
high to cause silicosis (3).
This celebration was premature for two reasons. First, current surveillance
data suggest that excessive exposure to silica is still occurring in the
United States. In the 1980s, the National Institute for Occupational Safety
and Health (NIOSH) conducted a national survey of 5000 workplaces in the
private sector to estimate the number of workers exposed to a variety of
chemical agents. In this survey, called the National Occupational Exposure
Survey (NOES), NIOSH estimated that approximately 135,000 workers were exposed
full time to silica. A much larger number of workers are exposed to silica
less than full time--approximately 1.7 million (4). This survey did
not measure the level of silica or include the mining industry, where silica
exposure is also common. Although not a representative sample of all workplaces
with silica exposures, databases maintained by the Mine Safety and Health
Administration (MSHA) and the Occupational Safety and Health Administration
(OSHA) report the results of all the environmental sampling they have conducted
(4). In the 1980s, 30% of the environmental samples analyzed were
above their permissible exposure limit (PEL) (Table 1). In 1991, 22 and
30% of samples collected by MSHA and OSHA, respectively, were over the PEL.
Combining these two sets of hazard surveillance information suggests that
silica exposure is both relatively common and sometimes excessive in an
unknown fraction of current workplaces. One risk assessment estimated that
approximately 25% of workers would develop silicosis if they were exposed
at the level of the current OSHA standard (0.09 mg/m3) for 30
years (2.7 mg/m3) (5). The number of deaths from silicosis
has gradually declined from 1157 in 1968 to 342 in 1989 (2). Also,
we do not know if the current exposure limits will prevent all silica-related
occupational lung disease or silica-related lung cancer.
Nevertheless, dissemination of information about the risks of silica
exposure probably has contributed to reductions in the levels of exposure
and incidences of silicosis. However, it is also clear that information
dissemination efforts have not completely solved the problem. At least in
occupational health, there is a recurrent theme of declaring victory before
the problem is eliminated, but that doesn't mean that there has not been
very substantial progress since the 1930s in reducing the extent of the
silica problem.
Conclusions
Several lessons can be drawn from this experience for effective prevention.
To improve the effectiveness of information dissemination, we need to better
understand whether our message is getting through to the right audience
and whether we are delivering the right kind of information. We also need
to understand the barriers to implementation of the information by workers
and management. For example, sometimes there is an effective method to reduce
exposure, such as wet drilling of silica-containing material. Yet, this
technology is not adopted universally, the research question becomes: What
are the barriers to wide use of this technology (cost, lack of knowledge,
technical problems, etc.)? We need to develop more effective hazard surveillance
data to enable monitoring to determine if numbers of workers exposed and
levels of exposures to occupational carcinogens are declining over time.
Since the latency between exposure and the subsequent development of cancer
often is greater than 20 years, hazard surveillance is particularly important
for occupational carcinogens.
In the past, cohort mortality studies have been effective in identifying
several carcinogenic exposures, such as asbestos and aromatic amino dyes,
that increased the risk of specific cancers several-fold (6). Currently,
the research challenge involves exposures that occur at lower levels than
those in the past, in a larger number of workplaces, each with fewer workers
and to agents that may be less potent. Nevertheless, the number of workers
exposed to agents that are known or suspected carcinogens is substantial
when one considers such common exposures as perchloroethylene, diesel exhaust,
radon, and man-made mineral fibers. In the future, epidemiological studies
with careful exposure assessments will still contribute important information
to our understanding of the effects of these agents. It is important to
recognize that while much has been achieved in the prevention of occupational
cancer, much remains to be achieved in better utilizing the existing information
and in conducting further research to expand our knowledge about the occupational
carcinogens.
REFERENCES
1. IARC. Silica and Some Silicates. Monograph 42. Lyon:International
Agency for Research on Cancer, 1987.
2. Steenland K, Loomis D, Shy C, Simonsen N. Occupational
causes of lung cancer. In: Occupational and Environmental Respiratory Disease
(Harber P, Schenker M, Balmes J, eds). Mosby, St. Louis, MO:in press.
3. Theriault GP, Burgess WA, Beradinis D, Fine LJ, Peters
JM. Dust exposure in the Vermont granite sheds. Arch Environ Health 28:12-16
(1974).
4. NIOSH. Work-related Lung Disease Surveillance Report.
NIOSH Publ No 94-120. Cincinnati, OH:National Institute for Occupational
Safety and Health, 1994.
5. Hnizdo E, Sluis-Cremer G. Risk of silicosis in a cohort
of white South African gold miners. Am J Ind Med 24:447-457 (1993).
6. Ward E. Overview of preventable industrial causes of
occupational cancer. Environ Health Perspect 103(Suppl 8):XXX-XXX (1995).
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