(CNN) -- A Greyhound bus accident along Interstate 80 in central Pennsylvania early Wednesday killed one person and injured more than 40, officials said. The incident happened in Union County south of Williamsport around 1:30 a.m., state police Trooper Matthew Burrows said. Five hospitals reported receiving a total of more than 40 patients from the accident. At least four of them were listed in critical condition Wednesday morning. The bus was traveling non-stop from New York to Ohio, carrying 49 passengers, a Greyhound spokesman said. The nature and cause of the incident weren't immediately clear; state police and a Greyhound spokesman told CNN only that it was under investigation. Westbound I-80 near the Williamsport exit was expected to remain closed until noon, Burrows said.
A Greyhound bus is involved in an accident on Interstate 80 in central Pennsylvania . One person died, and at least four of the 40-plus people injured were in critical condition . The nature and cause of the incident weren't immediately clear .