ARLINGTON, VA. — A new chemical industry study confirmed that workers at a Louisville, Ky., vinyl chloride monomer plant have a higher-than-normal rate of brain cancer deaths, but said it could find no evidence that it was related to VCM exposure. The study, prepared by the University of Louisville and funded with about $150,000 from the Chemical Manufacturers Association, said there is no evidence that current employees working at the plant are at risk for brain cancer.
All but one of the brain cancer cases occurred in workers who were hired in the 1940s and early 1950s, a CMA statement said.
"Further analyses may help determine whether other chemical exposures at the facility, particularly in the early years of operation, have contributed to the brain cancer excess," the study said. The plant also made PVC and ABS.
An Occupational Safety and Health Administration official who has studied links between VCM and diseases said he believes there is a link between brain cancer and VCM exposure.
Peter Infante, director of OSHA's Office of Standards Review, said brain cancer has a long latency period, and doing studies to find a specific link between exposure and cancer going back more than 20 years is tough. Lab animal tests and other studies have found links, he said.
Earlier studies that found a link between liver cancer and VCM prompted OSHA in 1974 to reduce permissible VCM exposure from 500 parts per million to 1 ppm.
The study was led by Richard Lewis, chief of the university's Division of Occupational Toxicology, Department of Medicine. It looked at 2,500 workers who spent at least a year there before 1973.
A 1999 CMA study reconfirmed a link between a rare liver cancer, angiosarcoma, and VCM exposure, but again concluded that current workers are not at risk.
"I would hope that Dr. Infante would acknowledge that the regulatory standards put in place in the mid-1970s have worked," said Kip Howlett, a CMA vice president. "He deserves credit, as does OSHA. As we have looked at other issues beyond liver cancer, we have confirmed there are not associations with regard to those other cancer endpoints."
The plant began making VCM for BFGoodrich Co. in 1942, but now its factories at the site are split between by BFG, Zeon Chemicals Inc., Geon Co. and Oxychem.