Flaring at Chevron refinery under investigation

Bay Area officials are investigating complaints about flaring at the Chevron refinery in Richmond on New Year's Eve.

The Bay Area Air Quality Management District said it received six complaints about the refinery on Dec. 31. 

Witnesses shared footage of the flaring with KTVU.

Chevron said the flaring was the "result of a process upset."

A level-1 warning, the least serious of 3 levels, was issued to the community, Chevron also said.