Flaring occurred Wednesday evening at the Chevron refinery in Richmond because a process unit was upset, Chevron officials said.
As of 9:22 p.m., the flaring had stopped after employees addressed the cause, Chevron spokesperson Amy Mosley said.
A Community Warning System Level 1 was issued because flaring was visible. On the CWS scale, Level 1 is one of the lowest, Mosley said.
The flaring was not a threat to the health of residents or the environment, according to Chevron.
Mosley said flaring helps keep the refinery running safely by relieving pressure in the refining process.
This post was originally posted at http://www.nbcbayarea.com/news/local/Flaring-Seen-at-the-Richmond-Chevron-Refinery-512875191.html.