MISSION VIEJO – Four businesses were damaged Friday morning after a fire started inside a sushi bar, prompting an evacuation of a nearby preschool.

Approximately 50 Orange County Fire Authority firefighters responded around 7:40 a.m. to Oishii Sushi, at 25542 Jeronimo Road.

Because of the heat, two firefighters each had first-degree and second-degree burns on their hands even though they were wearing gloves. A third had a shoulder and arm injury.

A pain-management office and a massage parlor were damaged by smoke and water before the fire was extinguished at 9 a.m. Smoke leaked into the fourth affected business in the strip mall.

“There was so much fire damage in the restaurant and our investigators spent hours, but as of this time, the cause will remain undetermined,” OCFA Capt. Steve Concialdi said.

The four suites suffered an estimated $1 million in structural damage, while approximately $500,000 in contents were destroyed in the sushi restaurant.

Contact the writer: 714-796-7802 or aduranty@ocregister.com