BP L.A. refinery Sunday upset quickly fixed-sources

HOUSTON, April 21 (Reuters) - A breakdown at BP Plc's (BP.L: Quote, Profile, Research) 265,000-barrel-per-day Los Angeles-area refinery in Carson, California, on Sunday was due to a faulty valve in the hydrogen plant that was quickly repaired, sources familiar with refinery operations said on Monday.

The breakdown triggered flaring at the refinery, according to a report filed with the South Coast Air Quality Management District, which regulates air pollution in the Los Angeles area.

The effect on the refinery's production was minor, the sources said.

A BP representative declined on Monday to discuss operations at the refinery. (Reporting by Erwin Seba)