Twelve firefighters were injured Sunday in a blaze that broke out at a commercial building, causing three chemical storage tanks to rupture and forcing the evacuation of 35 businesses, authorities said.

The injuries, including respiratory irritation and chemical burns, were all mild-to-moderate, said Jeff Lutz of the Anaheim Fire Department.

The fire was reported just after 4 p.m. Sunday near 4,000-gallon chemical storage tanks outside Alstyle Dyeing and Finishing, Lutz said. The blaze, which burned through combustible material near the tanks, was out in under two hours.

Two tanks of hydrogen peroxide and one of phosphoric acid burst open in the fire. While not flammable, both chemicals added to the heat of the blaze, Lutz said.

As a precaution, 35 nearby businesses in the industrial area were evacuated Sunday night as hazmat teams cleaned up the spill.

All the injured firefighters were expected to be back on the job this week.

The cause of the fire is under investigation.