RICHMOND (CBS SF) — A flare due to depressurizing equipment at the Chevron refinery in Richmond lit up the sky Thursday evening, causing a stir on social media.

Chevron issued a statement Thursday night saying that the flare was routing, saying, “We had a process unit that needed to be depressurized, creating a visible flare.  The flare is part of our safety system which enables to safely shut down a unit.”

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Social media users took to Twitter with pictures of the flare up wondering if there was a fire.

The flare was reflecting off steam that vents from the refinery’s equipment, making the brightness of the flare visible from miles away.

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Chevron said “In flaring conditions, it is normal practice to release quantities of water vapor (steam) to assist with the flare quality.  This sometimes can take on the appearance of smoke, but it is not smoke.”

Chevron often warns the community when large projects are taking place, but don’t always know when a flare is necessary.

Contra Costa County health officials said in a statement on Twitter that a hazardous materials team is on scene monitoring but that residents were not being advised to shelter in place.

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The refinery has been the scene of multiple fires in the past.