Fire was Chevron refinery's latest air quality violation

SAN FRANCISCO -- A massive refinery fire that sent hundreds of people rushing to hospitals and is likely to increase West Coast gas prices was just the latest pollution incident at the facility that records show has increasingly violated air quality rules over the past five years.

The Chevron oil refinery is one of three such facilities in Contra Costa County that are among the state's top 10 emitters of toxic chemicals, according to the U.S. Environmental Protection Agency's Toxic Release Inventory.

Chevron's Richmond refinery -- the scene of Monday's fire that shrouded the area in black smoke -- has been cited by San Francisco Bay Area regulators for violating air regulations 93 times in the past five years.

The number has increased from 15 violations in 2007 to 23 in both 2010 and 2011.