A passerby reported the fire at 10:45 p.m. Friday inside Joseph's Cleaners in the 3400 block of Torrance Boulevard. It took nearly 50 firefighters to knock down the flames.
Two firefighters were taken to a hospital for smoke inhalation and heat exhaustion. They were later released.
The business suffered an estimated $750,000 worth of damage. No other businesses were damaged.
Investigators continue to look into the cause of the fire.