There was no immediate word on Mary Rhoades' condition. The accident is being investigated.
The 66-year-old Republican had served for seven terms and was chairman of the Education Committee. He was campaigning for an eighth term.
A Senate Republican spokesman says the party would have to get a court's permission to remove Rhoades' name from the ballot and replace him.
He started in the Senate in 1981 and represents northeastern Pennsylvania's coal country.