The fire was reported shortly after 9:45 p.m. at 2575 Sandhill Road, according to Menlo Park Fire Protection District Fire Chief Harold Schapelhouman.
Callers reported heavy black smoke coming from the two-mile long particle accelerator structure directly under Interstate Highway 280, Schapelhouman said.
Fire officials worked with site staff to determine the source of the smoke, de-energize the accelerator and shut down as needed to allow safe access. In addition, they closed smoke control doors to isolate the affected area, according to Schapelhouman.
The smoke was affecting traffic on the highway but diminished once the accelerator area was de-energized, Schapelhouman said.
Firefighters used seven large mobile carbon dioxide extinguishing carts at the site to suppress the fire that appears to have started in a large electrical switching cabinet, he said.
Schapelhouman said the second alarm was called as a precaution.
The fire was under control around 10:30 p.m. and no injuries were reported, he said.
The cause of the fire is under investigation.
"Our crews have been well trained in the protocols and techniques needed to suppress and control fires at this facility," Schapelhouman said.
SLAC representatives meet monthly with the district's prevention bureau and quarterly with Schapelhouman to discuss all incidents at the site.
Stanford University operates the SLAC National Accelerator Laboratory, which opened in 1962, and is one of 10 U.S. Department of Energy Office of Science laboratories.
Copyright © 2014 by Bay City News, Inc. -- Republication, Rebroadcast or any other Reuse without the express written consent of Bay City News, Inc. is prohibited.