Chevron Corp. on Friday pumped $500,000 into an initiative campaign to curb punitive damages in California, boosting the refiner’s total contributions to $1.5 million over the last six weeks.

The donations make San Ramon, Calif.-based Chevron the largest donor by far to Californians for Sensible Lawsuit Reform, the committee financing efforts to put the measure on the November ballot. The initiative would shield manufacturers — in pending as well as future cases — from punitive damages if their products complied with applicable state and federal rules.