FOXBORO - The site of the Shell gas station at 32 Commercial St. (Route 140) is being evaluated to determine the extent of an underground petroleum leak, and a cleanup is under way, according to the state Department of Environmental Protection.

The site is currently fenced off, the gas pumps removed, and the convenience store closed.

The land is owned by Colbea Enterprises LLC of Cranston, R.I. The company did not return a call for comment this week.

The business is owned by Motiva Enterprises LLC of Wappingers Falls, N.Y.

An initial evaluation indicated that the release was relatively low level, DEP spokesman Joe Ferson said. "Elevated levels of compounds associated with petroleum were found in the groundwater and soil," during a "limited subsoil investigation" by a licensed site professional hired by Motiva, he said.

He said a potable water well located about 350 feet away at the Massachusetts Highway Department garage appears to be a safe distance from the release.

More assessment work is being done during the cleanup, Ferson said.

The gas station has four underground storage tanks, totalling 26,500 gallons. He said sometime a small leak can result in a detectable release.

The DEP is overseeing the cleanup to "protect the environment and to ensure the public safety," he said.