IXONIA, Wis. -- A senior citizens' trip to the Milwaukee botanical gardens turned into a fiery tragedy when their chartered bus slammed headfirst into a delivery van, killing five people and injuring 19.

The impact of Tuesday's crash shattered the bus windows and its bucket seats were tossed around. Two of the 15 elderly passengers were thrown from the bus and landed on the roadway.

The blue-and-white bus carrying 22 people crashed into a ditch 30 feet from the collision, killing Myrtle Neis, 82, Ruth Breitzmann, 84, and the bus driver, Carol A. Benisch, 61.

"You could see people collapsed," said Mike Leslie, 21, who witnessed the accident on state Highway 16, 30 miles west of Milwaukee. "People on top of each other. The bus driver was trapped. ... People were trapped on the floor and they couldn't get out."

The van, meanwhile, burst into flames, and the driver, Michael S. McNally, 35, of Mukwonago, was killed. Authorities had said cleaning solutions in the van fueled the blaze. But Ixonia Fire Chief Bruce Degner said Wednesday that company officials told investigators the van was not carrying cleaning chemicals when it crashed.

A fifth person, Evelyn Wendell, 91, died late Tuesday at Froedtert Memorial Lutheran Hospital.

Those taken to hospitals included a firefighter who injured his hand. A man and five women, all elderly, were in critical condition Wednesday, hospital officials said.

'Wondering'

Degner said some of the passengers were only semiconscious and most had serious injuries. "They were just sitting there wondering what happened," he said.

The bus, from the Marquardt Village retirement home in Watertown, was traveling to Milwaukee with four staff members and a volunteer, said Kyran Clark, the home's executive director.

"This is absolutely unheard-of in our town," said Sophie Traeger, 77, who lives in Watertown. "When you have a hole this big, you're going to know it and it's going to be hard to get over."

Leslie was driving behind the van when it turned left onto Highway 16. He was about to follow when he saw flames -- no van, just "fire and black smoke."

"And then through the flames came the bus and the bus slammed into the ditch," he said. "I couldn't believe it. It was just so fast."

The retirement village's chaplain was counseling residents at Zinzendorf Hall, an assisted-living center with 48 residents where the passengers on the bus had been residing.

Neis lived briefly with her son, John Neis, in Texas, but missed the Watertown area and opted to return there, the son said.

"She was an Alzheimer's patient. She loved the place where she was living. She was always happy," he said. "She always talked about how she enjoyed the meals there and how they were so nice to her. They were going to a botanical gardens, and she was excited and looking forward to that."