The pileup, which involved four buses, two cars and a pickup truck, occurred just after midnight yesterday at exit 41 near White Haven. Many passengers were asleep at the time of the crash.

The emergency response to the accident included 45 ambulances, 25 state troopers and at least 150 rescuers from all over eastern Pennsylvania, according to Pennsylvania state police.

At a press conference yesterday, Penn State President Graham Spanier thanked the emergency workers for their quick responses.

"We also want to express our most sincere condolences to the families of the two individuals who were killed," Spanier said.

Penn State officials said seven people were still hospitalized yesterday afternoon — including five with serious injuries — but hospital workers failed to say how many were still being treated last night.

One of the trip's organizers, Matt Sliwa (sophomore-marketing), was on the most severely damaged bus.

"I heard a bunch of shrieking and then the bus just plowed into us," said Sliwa, who suffered minor injuries.

On the same bus, Laura Snee (junior-American studies) said the impact threw her forward two rows of seats. Her face was covered in blood and she thought her nose was broken.

None of the four damaged buses overturned, but all had crumpled in a domino effect — one bus was smashed at the rear end, two others in the front and one at both ends.

Within minutes of the crash, emergency workers were using hydraulic machines to free victims from the mangled buses.

Officials are still trying to determine what caused the accident, but Spanier said a "thick wall of fog" played a role. He said police told him the buses were going slow with their emergency flashers on at the time of the accident.

Part of I-80 remained closed until 1 p.m. yesterday, about 13 hours after the accident, according to Wayne Gower, White Haven Emergency Medical Services captain.

Students who were unharmed or who sustained minor injuries climbed out through emergency exit windows. Those on the two undamaged buses exited onto the highway to comfort the injured during the rescue.

Victims, many with blood on their faces, shirts and legs, rode to hospitals in the ambulances. The remaining buses took the rest of the students to three churches in White Haven, which were set up as emergency shelters. Volunteers offered passengers hot chocolate, blankets and phones to call family members.

The company in charge of the buses, Blue & White Lines Inc. of Altoona, sent additional buses to gather students from hospitals and church shelters. The buses returned students to campus around noon yesterday.

Television crews, Spanier, friends and family greeted students as they arrived at the HUB/Paul Robeson Cultural Center. Penn State staff provided food, medical care and counseling services.

Spanier said faculty should be flexible with class assignments and attendance for those students involved in the crash. Fifty students involved the accident have already returned home for Thanksgiving break, Spanier added.

Jessica Miller (freshman-biology), who was injured in the crash, hobbled to the press conference on crutches. She said she was pleased with Penn State's response to the accident.

"We have been through hell last night and they are doing everything they can to make it better for us," Miller said.