HSIA study on perc nears completion
A study to assess whether workers exposed
to perchloroethylene have an increased risk of cancer should be
completed soon and published next year, according to the Halogenated
Solvents Industry Alliance.
HSIA, which is sponsoring the study, hopes
the new study will provide better data than previous exposure
studies because it focuses on a large population of workers
about whose exposure histories more is known.
Since it was undertaken more than two
years ago, the study has drycleaning workers identified from
the 1970 censuses in Denmark, Norway, Sweden and Finland, a
total of about 7,000 individuals. The 1970 census data has
provided 30 years of medical follow-up and reduced the
potential for exposure to other cleaning solvents used prior to
that time, HSIA said.
One benefit of the using data from the
Nordic countries is that much information is available from
surveys conducted by government, industry and other sources.
This, HSIA expects, will produce better data on worker
exposures than previous investigations. In Denmark, for
example, researchers were able to find historical information
on the identity of owners of all drycleaning shops and the
characteristics of the machines in use at each of the shops.
Also of benefit is that fact that the use
of perc was more pervasive in those nations 30 years ago than
in the United States. For example, the U.S. industry was about
evenly split between perc and petroleum in 1970, while 85
percent of the industry used perc in Finland, 75 percent in
Denmark, and 71 percent in Sweden.
The study will also benefit from
interviews with the individuals or their next of kin to help
fill gaps in the information available from other sources and
to allow collection of data on potential confounding factors.
The ability to identify life-style and other potential factors
has been a limitation of previous studies. Cigarette smoking,
for example, is an established risk factor for cancer of the
bladder, esophagus, kidney, and pancreas. Alcohol consumption
has been associated with both esophageal and liver cancer.
The study is looking at the incidence of
seven cancer types, including cancer of the bladder, cervix,
esophagus, kidney, liver and pancreas, as well as
non-Hodgkin’s lymphoma. Incidence of the various cancers
among the drycleaning workers will be compared to an age- and
gender-matched population of laundry workers.
HSIA said the study will be published in
the scientific literature sometime next year.
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