Fresno, Calif. ? Corpses piled up at the morgue Thursday, and aid workers went door-to-door, checking on elderly people in hopes of keeping the death toll from California’s 12-day heat wave from rising.

California coroner’s offices said the number of deaths possibly connected to the heat wave climbed to 90.

In Fresno County’s morgue, the walk-in freezer was stuffed with bodies, with some piled on top of others, said Coroner Loralee Cervantes. With limited air conditioning, employees worked in sweltering heat as they investigated at least 22 possible heat-related deaths.

The mercury dropped slightly in some areas, with Sacramento expected to get its first double-digit high in 12 days, but Fresno and Bakersfield were expected to hit 109.

Gov. Arnold Schwarzenegger announced that California was making 75 cooling centers available to residents at fairgrounds statewide. Health officials also were contacting nursing homes to make sure they had evacuation plans in place in case their air conditioning failed, he said.