"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 bus, with about 45 people on board, had been travelling since yesterday. 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 many seats, surrounded by police cars and ambulances.
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 from Galveston through Houston to Dallas. The crash site is roughly 17 miles southeast of downtown Dallas.
Gov. Rick Perry spokeswoman Kathy Walt said traffic on I-45 would be diverted at Ennis, about 30 miles southeast of Dallas. She said it was unclear how far the gridlock extended.Reuse content