SAN ANTONIO -- At least two passengers died when a Mexican tour bus crashed on I-37 Atascosa County on Tuesday morning.
The Americanos bus was carrying 42 passengers, including the driver. Two passengers died in the crash.
Efrain Dominguez-Valenzuela, 27, of Brownsville, and Christina Lozano Campos, 62, of Lewisville, were killed, officials say.
Three AirLIFE helicopters took seven patients from the scene to local hospitals, including University Hospital and Brooke Army Medical Center.
The bus accident happened near Campbellton just before 10 a.m. Witnesses initially indicated that bus blew a tire and swerved before crashing into the highway median. The driver says he heard a pop just before the accident happened.
But investigators say all of the tires on the bus are still intact. They are still trying to figure out what caused the crash.
Passengers say the ride was often bumpy, especially in the rear of the bus.
The bus was headed from San Antonio to Matamoros, Mexico. Both American and Mexican passengers were on board.
Many passengers were trapped inside the bus, and emergency crews had to rescue several passengers from the wreckage. Others crawled through windows to safety.
Americanos Autobus Co. -- which is owned by Dallas-based Greyhound -- has set up an information hotline for families of those involved in the crash. The number is 1-800-972-4583.
Families can also call the South Texas Regional Medical Center at 830-769-5320 to get updates on the victims' conditions.
The National Transportation Safety Board said it has not determined whether it will investigate, agency spokesman Keith Holloway said. A spokeswoman with the Federal Motor Carrier Safety Administration said the agency had just heard about the crash and was beginning to gather information.
Since 2002, more than 50 people have died in charter bus crashes around the state.
In 2008, a high-rofile accident in North Texas forced a federal overhaul of the industry. At tthat time 17 people died when an unlicensed charter bus hit a guardrail and ran off the road.
Investigators later revealed that the operator of that bus had been forced to shut down, only to re-open under a different name.
And last year, lawmakers required that all charter buses used by schools have seatbelts by 2011.
The Associated Press contributed to this report.
