BOZEMAN - A study is planned to determine whether harmful vapors from dry-cleaning fluid have migrated from a Bozeman shopping center into nearby homes.

The study, which is being conducted by the city and CVS Pharmacy, is related to the Bozeman Solvent Site on West Main Street. The contamination was caused by a former dry cleaner at the Hastings Shopping Center that disposed of the suspected carcinogen PCE through the sewer system.

Scott Dwyer, a senior toxicologist for Kleinfelder, an environmental consulting company hired to conduct the study, said any PCE that migrated into peoples' homes from the site would not reach levels high enough to cause sickness.

"If I was living in that neighborhood, knowing what I know ... I wouldn't be worried, but I would want additional testing to be done so we could understand the scope," he said.

The indoor air study was ordered because a study over the summer found that PCE levels in the area exceeded the screening level set by the state Department of Environmental Quality.

After the substance was initially discovered at the shopping center in 1989, septic and sewer systems were replaced or removed. PCE was removed through soil vapor extraction in the mid-1990s, and groundwater sampling is conducted on a semiannual basis.

About 10 percent of area structures are expected to be tested in the latest round, said Mike Ellerd, project manager at ATC Associates, the other environmental consulting company hired to conduct the study.

CVS assumed responsibility for the site in 2006 as part of its acquisition of the Osco Drug chain.