"We have, approximately, what we call 30 to 32 walking wounded," Police Sgt. Paul Shavack said after the Thursday accident in rainy weather in Bear, Del.
Forty members of the Phi Sigma Sigma sorority were being transported to a homecoming mixer when the tractor-trailer allegedly ran a red light and slammed into the side of the bus, WCAU-TV, Philadelphia, reported Friday.
Ambulances took nine of the passengers to Christiana Hospital and several others were transported by private vehicles, investigators said.
The passengers were all between the ages of 18 and 22, officials said.