HOUSTON, April 12 (Reuters) - April-delivery CARBOB gasoline finished with a gain of 1.25 cents a gallon at 11.25 cents a gallon over May NYMEX RBOB gasoline on Friday in the Los Angeles spot market, as refinery problems persisted in northern and southern California, traders said.
BP Plc (LSE: BP.L - news) .'s 240,000 barrel per day (bpd) Los Angeles-area refinery in Carson, California, has notified California pollution regulators that it will extend planned maintenance for another 10 days.
A source familiar with refinery operations said the work was part of routine spring maintenance and not a continuation of repairs to a hydrotreater that are set to finish early next week.
April CARBOB in the San Francisco Bay market climbed 7 cents to trade at 21 cents a gallon over May NYMEX RBOB.
In the Portland, Oregon, market, gasoline was steady with Thursday's finish at 6 cents a gallon over May RBOB.
April CARB diesel was also unchanged at 3.5 cents a gallon over May NYMEX heating oil in L.A. Bay market CARB diesel jumped 7 cents a gallon to 22 cents a gallon over May NYMEX heating oil.
Diesel in the Portland market retreated 1 cent a gallon to 10 cents a gallon over May heating oil.
L.A. April jet fuel slid 2.75 cents to 2.25 cents a gallon over May NYMEX heating oil.
CARB and CARBOB get their names from the California Air Resouces Board, which determines their formulas to reduce pollution-forming emissions in California cities. (Reporting by Erwin Seba; Editing by David Gregorio)