MARTINEZ -- A gas leak that caused black smoke to rise from the Shell oil refinery in Martinez on Tuesday was sealed by 3 p.m., in time for people to resume their outside activities, officials said.

"It is safe to be outside," said Randy Sawyer, the Chief Environmental Health and Hazardous Materials Officer for Contra Costa County.

A leak starting about 12:40 p.m. caused the black smoke, a refinery spokesman said. A piece of safety equipment called a flare began burning off the gas so the leak wouldn't combust, Shell spokesman Steve Lesher said

The Contra Costa County Health Department issued a health advisory at 1:31 p.m. A Level 2 warning alerted citizens that the smell of propane gas was noticeable off-site from the refinery, and that some residents might experience discomfort from their eyes, Sawyer said.

Shell is investigating the exact cause of the odor, the refinery reported on its website, and the equipment that leaked won't be used again until it's fixed. The gas was a "propane/butane mixture similar to what you would find in a barbecue," the notice said. The warning was lifted at 2:45 p.m. after the leak was sealed, Sawyer said. Shell identified the equipment failure early in the process, he said.

"There are no new odor complaints, and we're not picking up any new odors," Sawyer said.

No fire was reported and the nature of the leak posed no threat of a fire, Lesher said. A call for residents to shelter in place never occurred.


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The incident is the latest in a harrowing two weeks at area refineries. A small fire Monday at the Shell refinery was contained in about 10 minutes and prompted a Level 1 health threat, advising those with asthma or other breathing problems to remain indoors. That fire came one week after a massive fire Aug. 6 at the Chevron refinery in Richmond, which kept residents in Richmond, North Richmond, San Pablo and North Oakland indoors for several hours while fire crews battled the blaze. That fire shut down a major unit in the refinery, injured five employees and sent plumes of black smoke across East Bay communities into Tuesday morning. The county issued a Level 3 advisory, the most serious, for the Chevron fire.

Also last week, a shelter-in-place warning and sirens went off near the Shell refinery about 7:15 a.m. Wednesday. But it turned out to be a false alarm, police said. There was no emergency or fire that day at the Shell refinery.

Contact Rick Hurd at 925-945-4780 and Sean Maher at 925-943-8013. Follow Rick at Twitter.com/3rdERH and Sean at Twitter.com/OneSeanMaher.