A hazardous materials incident was reported at 12:30 p.m. at a building at 1120 Veterans Blvd., Deputy Chief Travis Nuckolls said. Amgen Inc. is listed at that address.
Crews found an unspecified hazmat situation and evidence of a flash fire, which is an sudden intense fire ignited when air mixes with flammable materials.
One worker was found with injuries and taken to a hospital, Nuckolls said.
The hazmat situation and fire was isolated to one section of the building, he said.
There was no threat to other parts of the building or nearby structures, Nuckolls said.
As of 4 p.m. crews were starting to leave the scene.
South San Francisco police, San Mateo County hazmat team and Office of Emergency Services and San Bruno fire also responded to the incident, he said.