A two-alarm fire scorched a Redwood City concrete and asphalt facility this afternoon, sending flames and smoke into the air for about an hour, a fire department spokesman said.
 
The fire at the Graniterock facility at 365 Blomquist Ave. erupted at about 2:25 p.m., and was brought under control by firefighters less than an hour later, spokesman Malcolm Smith said.

“It was quite a fire for a short period of time,” Smith said. He said about 10,000 gallons of a “liquid asphalt-oil mixture” in an above-ground tank burned. One employee suffered “very minor” burns, he said.

The cause of the fire is still being investigated.

“It’s a little unusual, so we definitely want to take a close look, and Cal-Osha will be taking a close look as well,” Smith said.