A massive fire that hit Chevron’s Richmond, Calif., refinery on Monday evening was contained but still burning on Tuesday morning. The plant is the third largest in California and accounts for one eighth of the state’s refining capacity. The fire started at 6:15 p.m. in the No. 4 crude unit, shortly after a leak had been discovered. Chevron said in a statement that there had been only one minor injury, but about 200 people have sought medical attention for respiratory problems. A February fire at BP’s refinery in Washington led to a three-month shutdown and sent the regional price premium to more than $1 per gallon.