SEATTLE (AP) — A "duck boat" tour vehicle and a charter bus carrying foreign college students collided on a busy Seattle bridge Thursday, killing four people and sending dozens to hospitals.
The collision happened on the Aurora Avenue Bridge, which carries one of the city's main north-south highways over a lake.
At least 12 people were in critical condition, and many others suffered lesser injuries, Fire Chief Harold Scoggins said.
There was no immediate word about the cause of the crash, which involved a military-style tour bus that can also be operated on water. Initial reports described the accident as a head-on collision.
A driver who was behind the duck boat said the tour bus and duck boat were headed in opposite directions.
Brad Volm of Philadelphia said the amphibious vehicle swerved in front of him. The left front tire of the duck boat appeared to lock up, and the vehicle swerved into the oncoming charter bus, he said.
Witnesses described hearing a loud screech and then seeing injured people lying on the pavement or wandering around in a daze.
Nurse Jahna Dyer said she was walking across the bridge when she came upon the scene, a mess of jumbled metal and glass. Some victims were lying on the road. Others milled about, seemingly in shock and falling down.
Dyer jumped a railing separating the sidewalk from the roadway and helped stabilize an injured man's neck. She said she also helped a woman who had a cut lip and glass in her eye.
"She was holding my hand and saying thank you," she said.
John Mundell said he was at the south end of the bridge when the crash occurred.
"We could hear the screech and twisted metal. It was surreal," he said, adding he saw what appeared to be a few dozen people on the ground. "I wanted to try to help. I felt helpless."
When emergency crews arrived, "a lot of people were running at them," pleading for help, Seattle Fire Lt. Sue Stangl said.
Bloodworks Northwest, a blood-donation organization, issued an urgent appeal for donors, saying the need for transfusions for crash victims was straining their supply.
The amphibious vehicle is operated by a tour company called Ride the Ducks, which offers tours that are known for exuberant drivers and guides who play loud music and quack through speakers as they lead tourists around the city.
Company President Brian Tracey said he did not know what happened. "Our main concern right now is with the families of those hurt and killed," he said.
The National Transportation Safety Board sent a team to Seattle to investigate.
Because foreign students were on the charter bus, efforts were being made to contact consulates, Mayor Ed Murray said. He had no other details.
Students and staff from North Seattle College's International Program were among those who were hurt. School spokeswoman Melissa Mixon said the uninjured students and staff were taken back to campus, where counselors were on hand.
The bridge was expected to be closed for hours. It has three lanes in each direction and no barrier separating the north and southbound lanes.
The safety of the amphibious boats has been questioned before. Lawyer Steve Bulzomi represented a motorcyclist who was run over and dragged by a Ride the Ducks boat that came up behind him at a stoplight in downtown Seattle in 2011.
"These are military craft that were never designed to navigate narrow city streets," Bulzomi said Thursday. "This is a business model that requires the driver to be a driver, tour guide and entertainer at the same time. It asks too much of the driver."
In 2010, a barge plowed into an amphibious vessel packed with tourists that had stalled in the Delaware River in Philadelphia.
The crash sent all 37 people on the duck boat into the river, but 16-year-old Dora Schwendtner and 20-year-old Szabolcs Prem never resurfaced. The Hungarians were visiting the United States through a church exchange program. Their families filed wrongful-death lawsuits.
A tug operator named Matt Devlin eventually pleaded guilty to involuntary manslaughter. Devlin acknowledged the accident was caused largely by his continuous use of a cellphone and laptop computer while he was steering the barge.
In July, the family of a woman struck and killed by an amphibious tourist boat in Philadelphia filed a wrongful-death lawsuit.
Attorneys for Elizabeth Karnicki's family allege the May 8 accident, which occurred during rush hour, was due in part to "huge blind spots" on the duck boats.
Associated Press writers Gene Johnson, Martha Bellisle and Lisa Baumann contributed to this report.