A study that links workers' miscarriages and chemicals used to make computer chips has raised questions about the safety of one of the nation's cleanest industries.
IBM recently notified its workers and competitors of a company-commissioned study that found that two widely used chemicals may significantly increase the risk.
The results were seen as significant, although they were preliminary and based on a small sample size, IBM spokesman Jim Ruderman said Monday. International Business Machines Corp., based in Armonk, N.Y., notified its workers, the Environmental Protection Agency and members in the Semiconductor Industry Association last month about the findings.
"In absolute terms they are not large numbers," Ruderman said. "Our feeling is that even one unnecessary miscarriage is too many."
Other companies in recent weeks have in turn notified their workers of the results of the study. Among them: Intel, Texas Instruments, American Telephone & Telegraph Co., Advanced Micro Devices, Signetics and National Semiconductor, said Semiconductor Industry Association spokesman Thomas G. Beermann.
The association has about 40 members, including virtually all the major semiconductor _ or computer chip _ manufacturers in the United States.
Beermann said the number of workers potentially exposed probably would be more than 1,000 but would be "a very small fraction of the approximately 200,000 U.S. semiconductor industry employees."
Industry watchdogs said Monday they have for years called for chip manufacturers to stop using the chemicals.
"We knew these were reproductive toxins, and the industry has known this," said Ted Smith, director of Silicon Valley Toxics Coalition, organized a decade ago to point to health concerns in the industry.
"It really seems that the people who are making the decisions in this industry care more about developing the next generation of chips than protecting the next generation of children."
The study by John Hopkins University researchers looked at 30 female workers who handled the chemicals at IBM plants in East Fishkill, N.Y., and Burlington, Vt., from 1980 to 1989. It found that the miscarriage rate among workers who did not use the solvents was 15.6 percent, compared with 33.3 percent among workers who did.
The chemicals _ diethylene glycol dimethl ether and ethylene glycol monethl ether acetate _ are used to etch away material deposited on the silicon wafers used to make chips.
There are no cost-effective substitutes for the chemicals, Beermann said, although in newer production plants "the use of these chemicals are certainly minimized." Most companies have begun offering their workers transfers from areas where they are used, he said.
IBM's Ruderman said changes have been made in the fabrication processes at the two plants, including purchasing the chemicals already mixed instead of mixing them on site. The new procedure dramatically decreases the risk of accidental exposure, he said.
IBM has reduced by 40 percent use of the chemicals since 1989, he said, and is stepping up plans to find substitutes and phase them out entirely.
The computermaker said it became concerned about the risks when a 1986 study at the University of Massachusetts for Digital Equipment Corp. indicated that some processes might be harmful.