SAN JOSE, CA — A frothy sea of bobbing white foam several feet deep spewed from a large hangar at Mineta San Jose International Airport in California on Friday, covering cars and blocking businesses on a nearby street.

By the afternoon, the sea of foam had surrounded two tanker trucks, reaching the bottom of a stop sign and spilling onto the street.

Crews asked people to stay out of the foam, but video showed a man on a bicycle emerging from the fluffy mass, covered in foam.

San Jose Fire Capt. Mitch Matlow told The Mercury News that the foam is a chemical used as a fire retardant and came from the hangar’s fire prevention system. Matlow said the retardant discharged accidentally and began spilling out Friday morning. Crews blocked the storm drains to keep the foam from spilling into the bay, and attempted to break up the bubbles and vacuum the mess.