BURLINGAME, Calif. -- A hazardous materials team from San Mateo Thursday was investigating a noticeable oily mass floating in canal waters south of San Francisco International Airport.

The 30-by-100-foot mass is not oil, but could be paint, according to a spokesman for the U.S. Coast Guard. Investigators say the substance could be paint, but they're still on scene examining it.

Early reports indicated the substance may have leaked from a vessel tied up in the vicinity of a seaside restaurant in Burlingame, Coast Guard officials said.

The sighting has prompted no advisory or evacuations.

"This situation does not yet seem to be a large issue but we want to get a handle on it right away," said Coast Guard Petty Officer Matt Doby.

The Coast Guard heard of the mass just before 6 p.m. Wednesday after Burlingame Fire Department crews found it and called the National Response Center.