RICHMOND (CBS SF) — A massive column of fire and smoke erupted from a stack at Chevron’s Richmond refinery Friday, triggering an alert to the local residents.

The flaring began around 11:45 a.m. and was visible for miles as nervous residents took to social media.

“The Chevron Richmond Refinery is currently experiencing flaring activity due to an upset at a process unit,” the company said on its facebook page.

“Due to the visibility of smoke, a Community Warning System Level 1 was issued to keep residents informed. Level 1 is one of the lowest in the CWS scale and no community action is required,” Chevron said in a Twitter post.

Company officials said flaring was a safety mechanism at the refinery.

“Flaring is an important part of keeping the Refinery running safely,” Chevron official said on Facebook. “Flares are a safety device used in refineries to relieve pressure during the refining processes and help keep our equipment and plants operating safely.”

Air monitoring teams from the Contra Costa Hazardous Materials Program were responding to the refinery to assess whether there is any risk to the community.

So far there have been no evacuation or shelter in place orders issued.

Compounding the problem with the flaring were the local weather conditions. A heat wave has blanketed the San Francisco Bay Area with a layer of hot, humid and very still air.

A ‘Spare The Air’ advisory had been issued by air quality officials early Friday.

“As temperatures and traffic increase in the Bay Area, unfortunately, so does unhealthy air quality,” said Jack Broadbent, executive officer of the air district. “When it matters most, we can protect our respiratory health and reduce our exposure to smog by avoiding outdoor activities during the hottest part of the day.”

Smog can cause throat irritation, congestion, chest pain, trigger asthma, inflame the lining of the lungs and worsen bronchitis and emphysema. Long-term exposure to ozone can reduce lung function. Ozone pollution is particularly harmful for young children, seniors and those with respiratory and heart conditions.

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