One critically injured student was transported by helicopter to the Albany Medical Center, where three other children and one adult hurt in the crash were in serious condition. Four others were in fair condition at the hospital and one was treated and released.
Forty-one other people were treated for less serious injuries at Bassett Hospital in Cobleskill, St. Peter's Hospital in Albany and Ellis Hospital in Schenectady.
"We have a room full of kids here, and we are currently in the process of preparing a list and notifying parents," Bassett Hospital spokeswoman Tina Swayze said.
A "plethora" of Bassett staff members had been called in to deal with the emergency, she said.
Schoharie County Sheriff John Bates said 21 ambulances were called in to transport the injured to hospitals, exhausting the small, rural county's supply of emergency personnel.
The students attended Albany School No. 18. Their bus crashed shortly after 10:30 a.m. in Schoharie County, about 30 miles west of Albany.
There were 44 youngsters, four teachers and four parent chaperones on the bus, Bates said.
The accident occurred along a two-lane strip of Route 7, at a four-way intersection with Zicha Road. The bus was traveling north across the intersection when it was hit in the right rear by the dump truck and spun 180 degrees. The bus rolled to a stop in grass about 500 feet away from the crash point.
The hood of the bus was ripped off by the impact.
Central Bridge Fire Chief Eric Johnson called it one of the most dangerous intersections in the area.
"This is something that we always hope never happens," he said.
Route 7 has a 55 mph speed limit, Zicha Road has a 30 mph limit.
Albany school officials told parents of the students on board the bus to meet at a local school so they could be taken to see their children. Crisis counseling teams were on hand at School No. 18 and the hospitals where the injured were taken.
Sandra Bowles of Colonie was at the school looking for her 7-year-old granddaughter Kimberly Johnson. The girl's mother, meantime, went to the Albany Medical Center to look for more information there.
"Parents are very confused," Bowles said. "Parents are very upset inside. School officials are trying to be helpful, they just don't have the information.''
Television scenes of the accident showed damage on the side of the bus. It was not upended and there was no fire.
Rescue workers swarmed the scene of the crash, and Albany Medical Center hospital workers labeled the event a Code D.
"That's our internal code to inform staff members that there is a disaster," Albany Medical Center spokeswoman Kathy Kuckerek said.
The childrn were on their way to the Pumpkin Patch, a traditional Halloween season field trip for school children in the region.