Consumers using paint strippers and spray paints containing methylene chloride -- one of the chemicals spilled at Union Carbide's West Virginia plant -- face a greater chance of getting cancer than with any other consumer product, according to a government study.
The risks from using spray paints and paint strippers containing methylene chloride "are among the highest ever calculated for chemicals from consumer products," the Consumer Product Safety Commission staff said at a closed briefing in June. About 600 million pounds of methylene chloride are produced or imported annually, according to estimates by the Environmental Protection Agency.
The CPSC is gathering information from producers on the substance's use, and plans to meet next month with industry representatives to discuss how the risks associated with the chemical can be minimized or eliminated.
Methylene chloride industry representatives said yesterday that, although they would cooperate with the CPSC, they doubted the agency's findings.
The four companies that manufacture the chemical are Dow Chemical Co. in Michigan, LCP Chemicals West Virginia Inc., Diamond Shamrock Corp. in Dallas, and Vulcan Materials Co. in Birmingham, Ala.
As many as 3,000 in every million persons exposed to paint strippers containing the chemical under "reasonably foreseeable consumer uses" may develop cancer over their lifetimes, the commission staff estimated. In contrast, the cancer risks from urea formaldeyhyde, used for residential home insulation, are 50 in every million people, according to the CPSC.
For aerosol spray painting operations using methylene chloride-containing products, individual lifetime risks are as high as 170 in one million, the report said.
"It is imperative that action be initiated to reduce consumer exposure from these products," the CPSC staff argued. An estimated 135 million retail-sized units of paint stripper are sold annually in the United States, while approximately 100 million units of spray paint are sold annually, the agency said.
"Of the products we've looked at, the paint strippers have the highest exposure levels," said Andrew Ulsamer, the CPSC's acting director for health sciences.
The CPSC study was based on testing of rats and mice by the National Toxicology Program, a unit of the Department of Health and Human Services. The risk assessment was based on use of the products once a year in a closed room such as a workroom or basement.
Using the products less often and in a well-ventilated room significantly reduces the risk, the report said. CPSC regulations require that products containing methylene chloride carry a warning label stating that they should be used only in a well-ventilated area.
The trade group representing the methylene chloride producers yesterday questioned the agency's findings and its testing methods.
"There are significant and serious questions as to whether the results from this one animal test are applicable to humans," said Jack Bonner, spokesman for the Halogenated Solvent Industry Alliance, which represents methylene chloride producers.
"It is important to note that the level of forced exposure to methylene chloride used in the test is not a level that consumers are exposed to in the proper use of products containing methylene chloride," Bonner added. "For instance, paint removers that contain methylene chloride are clearly labeled to be used in 'well-ventilated areas' and consumers are clearly warned to 'avoid prolonged breathing of vapor,' " he said.
Furthermore, Bonner added, it is highly unlikely that consumers would be exposed to as much of the chemical as the CPSC assumes.
Six workers and 136 residents were injured Aug. 11 at Institute, W. Va., when a chemical mixture containing methylene chloride leaked from a temporary storage vessel at the Union Carbide plant there. Consumers may also be exposed to methylene chloride in aerosol hairsprays and pesticides, government officials have said.
In May, the EPA said it would undertake an expedited review of the substance based on tests by the National Toxicology Program linking methylene chloride to cancer in laboratory animals. The Food and Drug Administration is reviewing its use in hair sprays and as a decafienating solvent in coffee, and the Occupational Safety and Health Administration is reviewing the effectiveness of its workplace-exposure guidelines to the chemical.