Witnesses who called 911 after the crash of a charter bus that killed at least 17 people described a chaotic scene, telling emergency workers of bloody passengers crushed beneath the smoking wreckage, according to calls released Saturday by police.

Click here to see photos.

The unlicensed bus carrying 55 members of a Vietnamese Catholic group from Houston to Carthage, Mo., for a religious festival smashed into a guardrail and skidded off a highway early Friday near the Texas-Oklahoma state line. Twelve people died at the scene and five more died at hospitals.

One emergency call began with a female crash victim speaking in accented English over the screams and moans of other passengers. After struggling to answer the 911 operator's questions, she handed the phone to a man who had apparently arrived at the scene immediately after the crash.

"We've got people crushed underneath the bus," the man said. "The bus is smoking. It might catch fire."

A female caller told a 911 operator that there were passengers "just everywhere out here laid out on the ground. They are bloody." Another caller said: "There's people screaming for help."

Most of the passengers were from the Vietnamese Martyrs Church and two other mostly Vietnamese congregations in Houston, heading to an annual festival honoring the Virgin Mary. The Marian Days pilgrimage, which started in the late 1970s, attracts thousands of Catholics of Vietnamese descent and includes a large outdoor Mass each day, entertainment and camping at night.

By late Saturday morning, traffic was back to normal and a damaged guardrail had been replaced. Several bouquets of carnations, tulips and roses were left on an embankment amid shards of glass and burned grass.

Authorities said the vehicle's right front tire, which blew out, had been retreaded in a manner that violated safety standards, said Debbie Hersman, a member of the National Transportation Safety Board.

After the tire blew out, the bus skidded about 130 feet before striking a guardrail, Hersman said. It then traveled nearly 120 feet before coming to rest down the embankment.

The driver, 52-year-old Barrett Wayne Broussard, had a commercial license, but his medical certification expired in May, according to the NTSB. Broussard was stable at a hospital. Authorities took blood samples from him Friday but do not have the results, Hersman said.

Broussard was convicted in 2001 of driving while intoxicated in Houston and sentenced to 10 days in prison and a $225 fine, according to state records. He has also been arrested at least three other times and was sentenced to two years in prison in 1998 for violating probation.

The bus operator, Iguala BusMex Inc. of Houston, had applied in June for a federal license to operate as a charter but was still awaiting approval, according to online records. The company recently filed incorporation papers, listing the same owner and address as Angel Tours Inc., which was forced by federal regulators to take its vehicles out of interstate service June 23 after an unsatisfactory review.

The review cited the company for problems in three areas: using a driver before receiving a pre-employment result, failing to require a driver to prepare a vehicle inspection report and using a driver who wasn't medically re-examined every two years.

A May 1 review by the Federal Motor Carriers Safety Administration cited the company for violations including a lax drug and alcohol testing program, Hersman said. Two of five drivers did not have current medical certificates, and 27 of 28 vehicle inspections were missing, she said.

Neither entity — Iguala nor Angel — is authorized to operate as a carrier in interstate commerce, according to the Federal Motor Carrier Safety Administration.

The bus was registered under temporary tags that were to expire Saturday, Hersman said. The NTSB is looking into the history of the sale of the bus, which was sold by a bus company in New York.

A man at Angel Tours in Houston declined to comment Friday. The company's voicemail system was full Saturday and not accepting new messages, and no one answered Saturday at a listing for the company's attorney.

"We're in the middle of a very intense investigation," attorney Keena Greyling told the Houston Chronicle, the newspaper reported Saturday on its Web site. "Because of that, we really can't discuss anything further."

Vu Pham, 35, of Houston, said his brother, sister-in-law, mother and 12-year-old nephew were on the bus. His brother, whose left leg has been paralyzed since he was a boy because of polio, remained in intensive care Saturday in a Sherman hospital, he said.

"We thought it would be better for him to get on the bus because it's a far drive," Pham said. "Now he keeps saying that he should have driven himself."

Authorities on Saturday released the names and ages of the 11 women and six men who died. The youngest was Thuy Thu Vu, 27, and the oldest was 89-year-old Cham T. Nguyen, who died at Harris Methodist Hospital in Fort Worth.

It was the nation's deadliest bus crash since 2004, when 15 people were killed in a wreck in Arkansas on their way to Mississippi's casinos. In 2005, 23 people were killed near Dallas when a bus carrying nursing home residents away from Hurricane Rita caught fire in bumper-to-bumper traffic.