CASPER - Wyoming environmental officials say an oily residue settled on some Newcastle homes and cars after an accidental release from a refinery.

The Department of Environmental Quality says the mishap occurred Wednesday night at the Wyoming Refinery Co.

Officials say refinery workers were restarting equipment at about 10 p.m. when the release occurred. Bob Neufeld, a Wyoming Refinery Co. vice president, says a power failure most likely caused the equipment to shut down.

Neufeld says there's no human health risk associated with the substance but he advises residents to avoid ingesting it or letting it come in contact with their skin.

Neufeld says the company is working with residents to clean up cars and houses.

The DEQ says it's sending staffers to the refinery.