REDWOOD CITY, California - A "mechanical problem" ignited a strecth-limo inferno that killed five nurses trapped in the back in May 2013, the California Highway Patrol said Monday as it released results of its investigation.The report included and emergency calls filled with screams from the trapped young women.Watch the videoThe limo caught fire on the San Mateo-Hayward Bridge on May 4 after the "catastrophic failure" of the rear suspension system, the Highway Patrol's Mike Maskarich said. The air-suspension failure allowed the spinning driveshaft to touch the floor pan, causing friction that ignited carpets and set the vehicle on fire.County prosecutors, speaking during a joint news conference involving the CHP, said no charges would be filed. The Public Utilities Commission, however, fined the limo operator the equivalent of about R15 000 for carrying more passengers than allowed.CELEBRATIONS GONE WRONGThe fire started while a nurse, Neriza Fojas, was celebrating her wedding with a group of friends. She was among the five who died. Four other women in the car, and its driver, survived.Recordings of emergency calls released on Monday included a woman shouting "Oh my God! Oh my God!" and a man's voice shouting "Get out! Get out!" There were also cries and screams from callers and passengers. One caller said: "It's a limousine that's fully engulfed and there are people trapped inside."A woman who said she was a passenger screamed as she told the dispatcher there were people inside the burning limo. On another call a rescuer told a dispatcher: "I don't think there is anything we can do. The rear of the limo is fully engulfed and the doors are locked."DRIVER MISUNDERSTOODInvestigators said the child-lock on one of the rear doors was engaged, the other was too burned to tell. One caller broke into tears as he described the scene to an operator who reassured him that help was coming.Authorities reviewed video and photos of the fire and interviewed survivors, including the limo driver, Orville Brown. Brown, 46, said at first, with the music in the limo turned up, he misunderstood what one of the passengers in the back of the 1999 Lincoln Town Car was saying when she knocked on the partition window."I thought she was asking if she could smoke," Brown said in an interview transcript. He added that, seconds later, the women knocked again, this time screaming, "Smoke, smoke!" and "Pull over." Brown said he got out and "tried to call 911, but it was busy".'HE DIDN'T OPEN THE DOORS'Passenger Nelia Arrellano, according to the transcripts, said she tried to get across to Brown that "there is already a fire, there is a fire already". Another passenger, Grace Guardiano, said the driver was "standing out there on his phone" after stopping the limo."He did not open the doors," Guardiano said. "I went out through the partition and called 911 from outside."Brown said he helped the four survivors escape through the partition.