A bus carrying elderly evacuees from Hurricane Rita caught fire and was rocked by explosions early Friday on a gridlocked highway near Dallas, killing as many as 24 people, authorities said.
"Deputies were unable to get everyone off the bus," Dallas County Sheriff's Department spokesman Don Peritz said. He said he believes 24 people were killed, but that number could change, the AP reports.
The bus, with about 45 people on board, had been traveling since Thursday. Peritz declined to give details on who the passengers were except to say they were from a nursing home in Bellaire, an upscale enclave within Houston.
Early indications were that it caught fire because of mechanical problems, then passengers' oxygen tanks started exploding, Peritz said. He said the brakes may have been on fire.
The bus was engulfed with flames, causing a lengthy backup on Interstate 45 already congested with evacuees from the Gulf Coast. The bus was reduced to a blackened, burned-out shell, with large blue tarps covering the bodies. About 20 emergency vehicles surrounded it.
Parkland Memorial Hospital in Dallas has been told to expect nine patients, said hospital spokeswoman Candace White. The most severe cases involved smoke inhalation, she said.
No emergency workers suffered major injuries in the blast.
Tina Jones was driving behind the bus when she saw it start to smoke and pull to the side of the road.
"I saw the smoke and then there was an explosions," said Jones, a nurse who pulled over and helped treat cuts and bruises. She said she saw at least six bodies.
Peritz said the driver survived. "It's my understanding he went back on the bus several times to try to evacuate people," he said.
Interstate 45 stretches more than 250 miles (400 kilometers) from Galveston through Houston to Dallas. The crash site is roughly 17 miles southeast of downtown Dallas.
Authorities were taking the unusual step of moving the wreckage to a remote location to continue the investigation there, so the interstate could reopen for evacuees, Peritz said.
"You have thousands of people who are in their vehicles trying to escape," he said.
Gov. Rick Perry spokeswoman Kathy Walt said traffic on I-45 would be diverted at Ennis, about 30 miles (50 kilometers) southeast of Dallas. She said it was unclear how far the gridlock extended.