The limousine that became engulfed in flames on the Hayward-San Mateo Bridge was authorized to transport eight passengers but was carrying nine, the California Highway Patrol said Monday.
The 1999 Lincoln Town Car is regulated by the state Public Utilities Commission, CHP Capt. Mike Maskarich said at a news conference in the highway patrol's Redwood City area office.
He said the regulatory mandates would be explored as part of a larger investigation into the fire that engulfed the car.
Maskarich and Foster City fire officials, who are assisting in the investigation, declined to elaborate on a possible cause or origin of the blaze, saying they have yet to review the vehicle's maintenance records, conduct more thorough interviews with the driver and survivors, or explore any potential recalls or other mechanical issues known to be associated with the model.
They said they did not yet know whether the stretch limo's two doors could be opened from the inside or whether there was a fire extinguisher on board.
Most if not all the passengers were nurses originally from the Philippines and were celebrating a bridal shower of one of the women, who planned to return to the Philippines for a second ceremony next month.
Five perished, including the bride, and four were injured.
The families of the deceased have provided dental X-rays, which will be compared later Monday to X-rays of the women's remains, San Mateo County Coroner Robert Foucrault said, adding that he expects to release the names of the dead late Monday or Tuesday.
The investigation into the cause of death will involve toxicology reports and take weeks to conclude, though the primary cause in cases such as this one is often smoke inhalation, he said.
Maskarich and Foucrault said the incident was the worst they've seen in decades of work.
"Any time we have a significant loss of life it's very difficult, but given the particular nature of what's transpired, it's just beyond words," said Maskarich, who said trauma counseling had been made available to all responders.
Foucrault said there was a floor-to-ceiling partition behind the driver with a glass window that opened. The deceased were "basically on top of one another, kind of huddled" below the window, indicating they were trying to flee the flames and get out.
Three good Samaritans stopped to help, among them an off-duty CHP sergeant, but were unable to free the women trapped behind the partition, Maskarich said.
The driver picked up nine women in Oakland on Saturday evening and was hired to drop them off about 40 miles away at the Crowne Plaza Hotel in Foster City for a bachelorette party, Foucrault said.
The women were riding in the passenger section of the limo when they noticed smoke coming from the back of the 1999 Lincoln Town Car, Foucrault said. They alerted the driver, who pulled over on the side of the San Mateo-Hayward Bridge.
When he got out of the limo to inspect the vehicle, he saw the rear was engulfed in flames, Foucrault said earlier. Three of the women managed to escape through the rear passenger door. Another squeezed through the partition that separated the driver from the passengers, he said.
Two of the surviving passengers -- Jasmin De Guia, 34, of San Jose and Amalia Loyola, 48, of San Leandro -- were taken to Santa Clara Valley Medical Center. They were being treated for smoke inhalation and burns and were listed in critical condition.
Two other passengers -- Nelia Arellano, 36, of Oakland, and Mary Grace Guardiano, 42, of Alameda -- were taken to Stanford Medical Center. They were treated for moderate burns and smoke inhalation, authorities said. Their conditions are unknown.
Driver Orville Brown, 46, of San Jose was not injured. Foucrault said he was "pretty distraught."
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