MARTINEZ — A yellowish cloud of dust billowing from a local oil refinery forced residents to seek shelter for the second time in four days.
Contra Costa County fire officials said the cloud began forming over Equilon Martinez Refining Co. around 8:50 a.m. Wednesday.
They said the situation was under control an hour later.
The county health department warned area residents to stay in their homes, with windows and doors closed and wet towels around all door and window openings.
The cloud was a sandy silica dust, according to Equilon spokesman Mark Hughes. He said it was not toxic.
Still, the cloud prompted the California Highway Patrol to shut down Highway 680 between the Benicia Bridge and Highway 4.
Hughes said the company did not know what caused the release.
It was the second accidental release in less than a week at the refinery.
Sunday night, the same unit of the refinery released alumina silica for just over an hour, prompting officials to issue a “shelter in place” order. The cause of that accident is still under investigation.
County health officials said those fluffy particles were not hazardous to touch and had no reports of anyone being injured. Equilon offered to pay to sweep city streets and school playgrounds, and said it would cover cleaning bills for cars, houses or other private property dirtied by Sunday’s black dust.