As the Bay Area struggles to adapt to a freeway system crippled by a collapsed interchange in its busiest corridor, questions persist.
Should tankers hauling such flammable material even be permitted to pass through such constricted spaces? Who should be allowed to drive them? And should the collapsed structure and other key traffic arteries be rebuilt to withstand another such conflagration?
“This is a wake-up call for the engineering community in California,” said Abolhassan Astaneh, a UC Berkeley civil engineering professor who studied the World Trade Center disaster and is investigating Sunday’s freeway collapse for the National Science Foundation.
Astaneh said his initial investigation indicated that two freeway segments failed in different ways. One came down after it was softened by the heat, and the other may have dropped after bolts and connections melted.
He suggested that the section of the 1950s-vintage freeway be strengthened to modern standards when it is rebuilt, but not initially fireproofed because it is unlikely that fire would strike that precise location soon. Policymakers should then identify all such sensitive freeway interchanges in the region and make them more resistant to fire and explosion, he said.
The tanker truck exploded in a spot where it was sandwiched between the two road levels, with only about 20 feet of space between the lower and upper freeway decks, Astaneh said. In such a tight space, disaster was not hard to foresee.
“To have a container of 8,600 gallons of fuel burning -- it is like steel skewers on a barbecue, and they get soft,” he said. “You put bare steel with no fireproofing, then you have a major problem, not a freak accident. This was an accident, but one we should have predicted as engineers.”
Sunday’s incident was not the first fiery tanker crash in the what is known as the MacArthur Maze east of the Bay Bridge toll plaza. In February 1995, a tanker carrying liquefied gas crashed and exploded on a nearby interchange, killing one person and injuring several. Authorities said speeding was a factor in the accident.
Jack Moehle, a structural engineering professor at UC Berkeley and specialist in reinforced-concrete construction, said that the degree of protection for the structure’s vulnerable steel underbelly was not very high on the interchange that failed Sunday, and that it should be rebuilt with fireproofing or precast-concrete construction.
“I am not suggesting these extraordinary measures would be appropriate everywhere, but certain structures like this one are critical to the economic viability of a region,” Moehle said.
Rather than attempt to fireproof such a structure, one bridge expert suggested that the routes of such fuel-hauling tankers be restricted in sensitive areas, or that the amount of fuel they haul be limited.
“You can regulate the trucking industry so there is less potential for destruction in a single vehicle,” said San Francisco engineer Mark Allen Ketchum, who has performed seismic work on the Golden Gate and Bay bridges.
Richard Leimbach, director of safety services and training for the California Trucking Assn., warned against such a “knee-jerk reaction,” saying truckers are subject to enough regulation and restrictions.
A 2006 U.S. Department of Transportation study of accidents involving commercial vehicles found that tanker trucks with various cargos were involved in 6% of the crashes -- while the more common closed trucks accounted for 34%.
California Highway Patrol Sgt. Jim Epperson, the agency’s head of hazardous material enforcement and emergency response, said some risk is unavoidable when transporting dangerous materials such as gasoline.
“If you build a big city and put a gas station in it, there’s no other way to get there except to go through the city,” he said.
Although federal laws require truckers to time their routes to “minimize the impact” of hazardous items traveling through populated areas, he said, “you can’t service all your gas stations only between 2 a.m. and 4 a.m.”
The question of who should be allowed behind the wheel generated fiercer debate.
After media reports surfaced that the tanker’s driver, James Mosqueda, had several drug-related convictions more than a decade ago -- one resulting in a prison sentence -- Assemblyman Pedro Nava (D-Santa Barbara) focused his blame on the hospitalized trucker and the licensing system.
On Monday, he called the fact that Mosqueda had secured a license “reprehensible” and questioned whether he should have been allowed to haul hazardous materials.
Though declining to discuss Mosqueda’s background in a Tuesday interview, Nava pressed for reforms of the federal Transportation Security Administration, which cleared Mosqueda for the work after a background check.
“The requirements are substandard,” said Nava, who heads the Assembly Transportation Committee and the Joint Committee on Emergency Services and Homeland Security.
CHP officials said alcohol and drugs were not involved in the crash. And family and friends of Mosqueda, who remained hospitalized with second-degree burns, have said he has long been drug-free and has dedicated himself to counseling and helping addicts.
According to the state Department of Motor Vehicles, Mosqueda had a valid Class A commercial driver’s license and a clean driving record.
The TSA also defended its background checks Tuesday. “He was going too fast. He may have fallen asleep. Would a more extensive background check have kept that from happening?” said agency spokesman Nico Melendez. “Our responsibility is making sure that people driving hazardous materials are not a threat. This person was not a threat.”
To obtain his clearance, Mosqueda submitted to a FBI criminal-history check and a background check by the TSA stretching back seven years.
If convicted during that period -- or released from prison within the last five years -- of offenses involving drugs, smuggling, immigration violations, assault with intent to kill, rape, weapons charges or robbery, an applicant cannot drive trucks carrying hazardous materials.
(Convictions that permanently disqualify an applicant include murder, espionage, terrorism, unlawful possession of explosives and treason.)
The California Trucking Assn. weighed in as well Tuesday, noting that trucking companies must do background checks on drivers for drug or alcohol abuse during the three years prior to hiring, and that Mosqueda deserved the job.
“My goodness, he paid his debt to society,” Leimbach said. “There’s no record of any wrongdoing since then.... It’s a proven fact: If they are gainfully employed, they don’t return to prison.”
On Tuesday, Bay Area commuters faced longer delays than on Monday, and ridership on public transit increased. Meanwhile, California Department of Transportation officials pressed ahead with a repair effort that most agree is moving swiftly.
At a news conference in Sacramento, Caltrans Director Will Kempton said the effort so far “has truly gone in textbook style.”
Engineers are trying to determine whether the damaged portion of Interstate 880 -- beneath the collapsed section of Interstate 580 -- can be fixed or needs to be demolished.
Meanwhile, debris from the top structure had been hauled away by midnight Monday.
So far, the state has spent $8.8 million on demolition activities, traffic control and free public transportation Monday.
Kempton said the administration was seeking federal reimbursement.
“I’m very heartened with discussions I’ve had with our friends at the Federal Highway Administration,” he said.
“This is a 24/7 operation,” he said of the project.
“We are going to be working around the clock.”
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Times staff writer Evan Halper contributed to this report.