He said it was too early in the investigation to say whether overcrowding may have been a factor in the deaths. Investigators have conducted preliminary interviews with the survivors and the driver, but more in-depth interviews, as well as an inspection of the gutted vehicle, were still needed.
It will take a few weeks for investigators to piece together "some semblance of answers for the tragic events that just occurred," Maskarich said.
Debris or any other objects on the roadway do not appear to have been a factor, he said.
By the time the Foster City Fire Department reached the blaze, almost 12 minutes after the first 911 call, there was no hope of saving anyone.
"We are devastated by this incident," Foster City Fire Chief Michael Keefe said.
A spokeswoman for the California Public Utilities Commission, which regulates limos, said Monday that the limo owner, a company called Limo Stop, is licensed and has shown evidence of liability insurance. The company has seven vehicles with a seating capacity of up to eight passengers listed with the CPUC. It has not been the target of any previous enforcement action. Limo Stop received its permit in June 9, 2006, the agency said.
The CPUC requires that all carriers have a preventive maintenance program and maintain a daily vehicle inspection report, said spokeswoman Terry Prosper. Carriers also certify that they are have or are enrolled in a safety education and training program, she said.
Prosper said requirements for emergency exits only apply to buses.
Joan Claybrook, the top federal auto-safety regulator under President Jimmy Carter, said the stretch limousine industry is poorly regulated because the main agency that oversees car safety doesn't have enough money to prioritize investigating the small businesses that modify limos after they leave the assembly line.
"I think the oversight is pretty lousy, because the modifications are so individualistic, and there are not that many companies out there that do this. Mostly, they are mom-and-pop operations," said Claybrook, a former administrator at the National Highway Traffic Safety Administration who previously led consumer group Public Citizen. Instead, the agency tends to focus more on problems with new cars and major recalls, she said.
U.S. Department of Transportation data shows five people died in three separate stretch limo accidents in 2010, and 21 people died in another three stretch limo accidents in 2011.
Stretch limos are typically built in two ways.
In the first process, one car maker builds the limousine's body, then another company customizes or stretches the vehicle. The second company has to issue a certification that the car meets National Highway Traffic Safety Administration safety standards for new vehicles, and that all safety equipment is working as required before it can be sold to the public, said Henry Jasny, an attorney with the Washington-based nonprofit Advocates for Highway and Auto Safety.
In the second process, a customer buys the limousine directly from the car maker, then takes it to be customized. But modifying the car after it has been sold is considered a retrofit, so is not something NHTSA would regulate, Jasny said.
Many older models such as the 1999 Lincoln Town Car that caught fire Saturday were modified after they left the factory, said Jerry Jacobs, who owns a boutique limousine company in in San Rafael with a fleet that includes two stretch limos.
"There is nothing wrong with having these older models on the road. Many have low mileage and immaculate interiors because we take care of them. But when these cars start getting older and the rubber boots wear out, they start running hot," Jacobs said. "The key is you have to keep doing all the right maintenance to make sure they're running smoothly."