Fatal Blast Probe Could Take Weeks : Safety: Three investigations are under way. Daughter of a Rockwell engineer who died in the explosion praises him as a dedicated scientist.

As relatives mourned two engineers who were killed at Rockwell International’s rocket engine test site near Simi Valley, investigators continued searching Wednesday for clues to the cause of the fatal chemical explosion.

Rockwell officials said it could be 10 days to several weeks before three separate investigations into Tuesday’s blast at the Santa Susana Field Laboratory are completed.

“We have put together what we are confident is the best team of experts available to us,” said Paul Sewell, a spokesman for Rockwell’s Rocketdyne Division. “And we’re going to look at every possibility.”

In addition to Rockwell, the Ventura County Fire Department and the California Division of Occupational Health and Safety are conducting investigations into the accident, the first at the lab involving fatalities since the 1960s.

Rocketdyne engineers Larry A. Pugh, 51, of Thousand Oaks and Otto K. Heiney, 53, of Canoga Park were killed instantly and a third man was seriously injured in the explosion at the 2,700-acre hilltop facility.

The men were preparing for a controlled burn of a catalyst used in solid rocket fuel motors when the accident occurred at 9:07 a.m., officials said. Two unidentified Rockwell workers involved in the outdoor test escaped injury.

“A lot of people lost their friends,” Sewell said, describing the mood of employees at the lab Wednesday, where work went on. “We’re not taking it well.”

Pugh, who had worked for Rockwell since 1977, lived in the Sunset Hills neighborhood of Thousand Oaks for 17 years with his wife, Antoinette, and daughter Meredith, 21.

Meredith Pugh, a student at Loyola Marymount University, described her father as extremely dedicated to his work.

“He absolutely loved his job,” she said. “He had a real passion for science.”

When she was in high school, she said, her father helped her research science projects and experiments. Although she said she was never scientifically inclined, she said that was fine with her father, who had a deep sense of pride about his family.

Pugh said her father never mentioned any fears associated with his work at Rocketdyne.

“He was never afraid,” she said. “He was very brave.”

Heiney’s survivors live in Florida and could not be reached for comment.

Rockwell test mechanic Lee Wells, 62, who suffered second- and third-degree burns over 20% of his body, was listed in stable condition Wednesday. The Newbury Park resident is being treated at the burn center at Sherman Oaks Community Hospital.

None of the three investigative agencies was able to shed new light on the cause of the accident. Sewell said that the men were working on an experiment for Rockwell, not for a private contractor.

Cal/OSHA sent two inspectors to Santa Susana immediately after the accident, spokesman Rick Rice said. One inspector will focus on possible worker safety violations, and the other on possible criminal activity associated with the explosion.

“It’s impossible to say at this point how long the investigation is going to take,” Rice said.

In the event any worker safety regulations were violated, a citation would be issued, which could range from a maximum penalty of $7,000 for one violation to several hundred thousand dollars for multiple violations, he said.

Rocketdyne has received six citations since 1990, all for minor health and safety violations, including one $300 fine for failing to keep a proper log of injury accidents, Rice said. Other records of citations were not available.

The Santa Susana Field Laboratory, which employs 742 workers, is a renowned rocket engine test site for the Air Force and the National Aeronautics and Space Administration. The facility has been in operation since 1947, when it was opened by Rocketdyne’s predecessor, North American Aviation.

Rockwell officials said Tuesday’s fatalities were not the first to occur at Santa Susana. Six workers were killed in various accidents at the facility in the early 1960s, Sewell said.

Times staff writer Mary Pols contributed to this story.