Work Halted at Facebook Site After Building Collapse Injures 2 Ironworkers

State workplace regulators have launched an investigation into the partial collapse of a building under construction on Facebook's Menlo Park campus that sent two ironworkers to the hospital and placed scrutiny on two construction companies that have done work on some of the Bay Area's most high-profile projects.

Four beams on the new building dislodged from the steel supports at 5:25 p.m. Wednesday, according to Level 10 Construction, the project's main contractor. The two men were on a team that was putting up the steel frame of Facebook's new Building 21 that was designed by Frank Gehry. Work was halted after the accident.

"There was a catastrophic failure of some kind," said Menlo Park Fire Chief Harold Schapelhouman.

The workers were on one of the beams that dropped, got caught on a lower floor assembly and catapulted them toward the ground, according to Schapelhouman.

"These guys are slinging big steel. When you're using cranes and dealing with thousands of pounds of steel beams it's not easy work, and something obviously went wrong," Schapelhouman said in an interview.

The workers fell about 30 feet to the ground, Level 10's president Dennis Giles said in a statement.

Both injured men were wearing protection equipment.They were transported to Stanford Medical Center. One of them was released from the hospital last night, The other is under observation, according to Giles.

Level 10 has worked on other Facebook projects and has done jobs for Stanford University, Sutter Health, Oracle, UC San Francisco and 181 Fremont, which is a new 60-story high-rise near the Transbay Terminal in downtown San Francisco

The workers were employed by a subcontractor, Schuff Steel, a Phoenix-based structural steel fabricator and erector, which has done work on a number of major high-profile projects, including Apple's corporate headquarters.

Representatives of Schuff have yet to return requests for comment and Facebook is not commenting.

The collapse damaged a number of steel upright crossbeams, Menlo Park fire officials said. But Level 10 representatives have not released the extent of that damage.

California's Division of Occupational Safety and Health (Cal/OSHA) is investigating the incident, and both Level 10 and Schuff will be the focus of its probe, said Cal/OSHA spokesman Frank Polizzi.

The state agency has investigated Schuff on eight occasions since 2013 and fined it several times. Last year Cal/OSHA fined the company more than $18,000 in connection with an accident at a Stockton construction site. In 2013, it was fined more than $30,000 for violations stemming from an accident at a San Diego site.

Cal/OSHA has investigated Level 10 eight times in the last three years but has not fined the company in connection with any of those probes.