Workers return after gas leak in Bldg. 511

Five employees have returned to work after a minor leak of an industrial chemical gas Wednesday afternoon sent them to Valley Care hospital for observation for possible chemical inhalation. They were released Wednesday evening.

The accident occurred at approximately 3 p.m. in Bldg. 511 (Shops area) when Lab workers working on a metal cylinder inadvertently released the gas. The workers immediately left the room and notified Laboratory Hazards Control personnel. Emergency responders evacuated the building as a precaution. Approximately 250 people were evacuated. There was no danger to other employees, the public or the environment.

"Laboratory emergency workers did a terrific job of quickly responding and managing the incident," said George Campbell of the Safety and Security Directorate and the LLNL emergency duty officer. "It was a real team effort right down to the mutual aid support we received."

The building has reopened for business, with the exception of the room where the incident occurred. Lab investigators are conducting an investigation into the cause of the incident to try to determine how to prevent a similar incident in the future.

The gas, rhenium hexafluoride, is a corrosive acid that could cause lung damage if inhaled in sufficient quantity. The chemical is used in industries such as computer chip manufacture for vapor deposition of materials.