RICHMOND (CBS SF) — A possible hazardous materials spill found in the water near the Chevron Refinery in Richmond has been contained, according to Chevron officials.

The spill Friday morning was “quickly boomed by our emergency response team,” according to a statement from Chevron.

“This morning around 6:30 a.m., a soot-like material was identified in the water between a berthed ship and our long wharf,” Chevron officials said in a written statement. “The material is contained and we are investigating the source.”

Chevron officials did not say how much of the material was spilled or what they think it is.

Contra Costa Supervisor John Gioia first reported the spill of a “black solid substance” via Twitter at about 9:20 a.m.