RICHMOND (CBS SF) – Flaring at the Chevron Refinery in Richmond Tuesday afternoon sent a large plume of black smoke into the sky that could be seen across the Bay Area.

Around 3 p.m. Contra Costa Supervisor John Gioia tweeted that the smoke is likely from a flaring incident at the refinery. Smoke from the area was visible throughout western Contra Costa County and as far away as Marin County.

READ MORE: UPDATE: All Lanes of Westbound I-580 In Oakland Reopen Following Police Activity

Shortly before 4 p.m., refinery officials issued a statement to KPIX 5 which read in part, “A safety flare was activated for a short time due to a process upset that was quickly corrected this afternoon. A Community Warning System Level 1 – the lowest on the scale – was issued to keep residents informed.”

Richmond firefighters also said the incident at the refinery was at Level 1, the lowest in severity. “No actions by the public are needed,” firefighters tweeted.

READ MORE: Oakland School Board Discusses Reinstating Popular Police Mentoring Program

In a report submitted to the state’s Office of Emergency Services, the refinery said an “unplanned upset” occurred around 2:40 p.m., causing the release of sulfur dioxide. It was not immediately known how much was released and that the release is not impacting waterways.

The smoke could be seen from miles away and is the latest incident involving the Chevron refinery, which has already had multiple cases of flaring this year and also spilled several hundred gallons of oil at its long wharf in February.

The Bay Area Air Quality District said a tweet that they are monitoring the incident. 

MORE NEWS: Supply Chain Crisis: Shipping Industry Leaders Meet In San Francisco, Warn Backlog To Stretch Long Past Holidays

Air District inspectors are on scene investigating and we are working to find the root cause of the smoke in addition to any potential air quality violations,” the district said.