Los Angeles Fire Department investigators stood with puzzled fascination, trying to recreate exactly what happened. There, in the midst of the debris, were two black tanks. One of them was blown to bits. Part of it was still discernible. But where was the rest of it?
Such was the intricate process of figuring out just what happened late Tuesday afternoon in Sylmar, where two men were critically injured in a very big explosion.
The Los Angeles Police Department even flew a helicopter over the scene, trying to find crucial bits of debris evidence from high above the scene.
"We're ensuring that the remnant was not launched into a neighboring business," said Capt. Jaime Moore, spokesman for the Los Angeles Fire Department. Cal OSHA and the LAPD were also involved.
The blast left off duty firefighter Tim Larson with critical injuries. Larson, it turned out, was an owner of the alternative fuel company called Rainbow of Hope. In a cruel twist, Larson's brother, Tyson, had been killed in a similar accident last June at a business in Simi Valley.
Cal OSHA, which took over the investigation Wednesday, also investigated the Simi Valley explosion. The safety agency concluded that over-pressurized tanks and improper maintenance contributed to that accident.
"That project in Simi Valley was shut down because Ventura County did not allow it to continue," said Erika Monterroza of Cal OSHA.
Monterroza said last year's incident resulted in three citations being issued by Cal OSHA, and fines totaling $5,685. The fines are under appeal.
Still, what was learned in Simi Valley could be useful in sorting through what happened in Sylmar. And then there are questions about whether the Sylmar operation had appropriate permits.
"They are required to identify the type of business it's going to be," said Moore, of the fire department. "That's part of the investigation."