Cause of Explosion Sought in San Jose

Investigators were trying Friday to determine the cause of an explosion that destroyed a San Jose laboratory and office building. Executives at Pratt & Whitney Space Propulsion said it remained a mystery.

“We are still determining the extent of damage and are working diligently to find the root cause of this incident,” said Larry Knauer, president of the Space Propulsion unit of P&W;, a division of United Technologies Corp. that formulates liquid, solid, electric and hypersonic rocket propellant. “We are working closely with internal, local, state and federal officials to examine every facet of this occurrence and to resume normal operations.”

Shortly before 6 p.m. Thursday, an explosion demolished P&W;’s three-story facility in the foothills of south San Jose. The blast shook homes within a five-mile radius and set off a 20-acre grass fire, which sent a plume of thick smoke over the surrounding residential and rural area. The fire was extinguished by 8:30 p.m.

No one was injured in the incident. The nearest P&W; employee was about a quarter-mile from the building, in a remote bunker where workers seek refuge when mixing volatile fuels.

Hartford, Conn.-based UTC is an aerospace and manufacturing conglomerate.

About 700 employees on multiple shifts make solid rocket motors for missiles, shuttles and communications satellites at the San Jose facility, which is run by UTC’s P&W; Space Propulsion division, based in West Palm Beach, Fla.

Employees reported to work Friday morning on the 5,000-acre San Jose site, which has been in operation since the 1960s.

The state’s Department of Toxic Substances Control inspects the facility about once each year, according to the California Environmental Protection Agency.

The last inspection was completed in April 2002, leading to a citation for minor violations, according to the EPA’s Web site.