EH-93-2 Occupational Exposure to Epoxy Resins, Hardeners and Solvents
             OFFICE OF EPIDEMIOLOGY AND HEALTH SURVEILLANCE
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                            HEALTH BULLETIN
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U.S. DEPARTMENT OF ENERGY                             WASHINGTON, D.C.
Issue 93-2                                               February 1993
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     Occupational Exposure to Epoxy Resins, Hardeners and Solvents


A new study of workers at the Department of Energy's Oak Ridge
Gaseous Diffusion Plant (ORGDP) was published in the December 1992
issue of the Journal of Applied Occupational and Environmental
Hygiene (7:826-834, 1992).  The purpose of the study was to
determine if workers exposed to certain chemicals in centrifuge
rotor manufacturing and testing processes had higher rates of
cancer or other diseases than other workers at the plant.  Between
1963 and 1985 centrifuge rotors were manufactured from fiber
reinforced epoxy resins and were built on automated machines
controlled manually by operators.  These workers were potentially
exposed to several types of chemicals and solvents used in the
process.

All workers whose jobs were likely to involve routine exposure to
epoxy resins, amine hardeners, or solvents in centrifuge rotor
manufacturing or testing processes were identified from plant
employment records.  These centrifuge plant workers are referred to
as the exposed group.  Employees who did not work in the
centrifuge rotor manufacturing area were eligible to be in the
comparison group (unexposed).  To ensure that the two groups were
comparable with respect to other factors (see epidemiologic note)
that could influence disease rates, the unexposed workers in the
comparison group were matched to the centrifuge workers by age,
race, sex, and date of hire.  Each exposed and unexposed worker
was interviewed by telephone to collect information on his complete
job history, lifetime occupational exposures, smoking habits,
alcohol consumption, and other factors related to health.  A total
of 263 centrifuge workers and 271 unexposed workers were
interviewed.

The centrifuge workers were more likely than the unexposed group
to report having worked with benzene, chromium, radioactive
materials, trichloroethylene (TCE), phenol, and methylene chloride. 
These exposures could have occurred in any job at ORGDP or during
employment elsewhere.

The centrifuge workers were more likely than the unexposed group
to report having experienced symptoms like dizziness and numb or
tingling limbs.  These symptoms have frequently been reported in
the scientific literature to occur among workers who have high
exposures to solvents.  The centrifuge workers were more likely
than the unexposed group to report experiencing skin rashes,
which are known to be associated with epoxy resin exposure.  The
centrifuge workers were more likely than the unexposed workers to
have had kidney stones. 

Five of the centrifuge workers were diagnosed by their physicians
as having bladder cancer, while none of the workers in the
unexposed group reported having bladder cancer.  The five bladder
cancers occurred 10 to 20 years after beginning work in the
centrifuge process.  Although one of the epoxy resins used in the
early years of the centrifuge process at ORGDP may be associated
with bladder cancer, none of the five workers had any job that
required hands-on work with this or any other epoxy resin
materials.  However, four of these workers reported having been
exposed to solvents.  All five of the workers were former or
current smokers.  With the information available for this study,
the researchers were unable to identify a specific cause for the
bladder cancers.

No other conditions were reported to occur with significantly
greater frequency among the centrifuge workers than among the
unexposed group.  Because the cause of the bladder cancers is
unknown, it will be necessary to continuously monitor these
centrifuge workers for the occurrence of cancer and to continue to
investigate the types of exposures the workers with cancer might
have had in common.  Martin Marietta Energy Systems has initiated
a comprehensive screening program for former workers in the
centrifuge process.  Under a Memorandum of Understanding, further
epidemiologic studies of these workers will be managed by the
National Institute for Occupational Safety and Health.


      Epidemiologic Note:

      Disease rates vary by many different factors like age, sex, ethnic
      background, and others.  For example, cancer rates are higher in
      adults over the age of 50 years than in younger adults.  When a
      factor is related both to the disease and to the exposure of
      interest, it is called a confounder.  For example, age is related
      to disease rates and is also related to certain employment factors
      like the number of years employed.  If an exposed group and a
      comparison group are different with respect to one or more of these
      confounders it is difficult to determine whether differences in
      disease rates are due to the exposure or to the confounder.  To
      control for the effects of these confounders, epidemiologists use
      several techniques.  One technique is to adjust for the
      confounders in the analyses.  For example, the rate of disease for
      each age group in the exposed group is compared with the
      corresponding rates by age group in the comparison group.  Another
      technique is to select a comparison group with the same
      distribution by the confounding factors (e.g., age, sex, race) as
      the exposed group.  This is called matching.



      This Health Bulletin is one in a series of routine publications
      issued by the Office of Health to share data from health studies
      throughout the DOE complex.  The authors conclusions do not
      necessarily reflect those of the Department.  For more information
      contact:  Dr. Terry L. Thomas, Director, Health Coordination and
      Communication Division, Office of Epidemiology and Health
      Surveillance, U.S. Department of Energy, Washington, D.C.  20585;
      Telephone (301) 903-5328.
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