HOUSTON (Reuters) - A malfunction on the gasoline-producing fluidic catalytic cracking unit at BP Plc's 240,000 barrel-per-day Los Angeles-area refinery in Carson, California, triggered flaring on Thursday, according to industry and trade sources.

BP reported unplanned flaring at the refinery to California pollution regulators but did not specify the cause of the problem.

A BP spokesman declined to discuss operations at the Carson refinery Thursday morning.

(Reporting by Erwin Seba)