joe hu/town crier Workers clean up damage caused by a two-alarm fire at St. Francis High School in Mountain View last week.

A two- alarm fire burned the roof and ceiling of the cafeteria building at St. Francis High School Sept. 5, according to the Mountain View Fire Department.

The fire spread after someone apparently dumped used barbecue coals in the dumpster adjacent to the building. The coals possibly were dumped after a Friday night back-to-school event, said St. Francis spokeswoman Kate Kiely.

Someone driving by the high school reported smoke and flames. When firefighters arrived, they found the 300 building on fire and began quick fire-attack operations.

Mountain View Fire Department spokesman Lynn Brown said nobody was hurt.

He cautioned that dumping coals without properly extinguishing them was potentially dangerous.

“You’ve got to either dump water (on the coals) or put them in a metal container,” Brown said. “Coals can smolder for days and if they’re exposed to air, they can combust.”

Damage estimates have not been made yet.