Heat prompts power emergency in Calif.

SAN FRANCISCO - Power companies worked to restore electricity to thousands of customers throughout California early Monday as a scorching heat wave threatened to push the state into a power emergency with the potential for more blackouts.

Authorities were looking into several deaths possibly related to the high temperatures, which hit the triple digits in some areas on Sunday.

With temperatures again expected to top 100 degrees, power demand was projected to reach an all-time high Monday and prompt some voluntary blackouts, in which some businesses agree to have their power shut off temporarily in exchange for lower rates, according to the Independent System Operator, California's power grid manager.

Those blackouts could become involuntary if customers don't conserve electricity, said ISO spokesman Gregg Fishman.