Summary:
A hayride in Maine has sparked a major investigation, with at least 15 people injured, including two people, being treated in hospital.

Full article:
(CNN) -- A trailer carrying revelers on a haunted night ride overturned Saturday in Maine, sending at least 15 people, including two by helicopter, to area hospitals, a fire official said. The accident happened during what's called The Gauntlet, a spooky hayride through forest and including "things that jump and scream in the night." The activity is part of Pumpkin Land, a venue featuring a variety of Halloween-themed activities in Mechanic Falls, about 30 miles north of Portland. David Clukey, of the Mechanic Falls Fire Department, said multiple people were injured when the tractor-trailer flipped. Seven fire departments and three police departments -- including state police -- rushed to the scene, according to Clukey. Clukey didn't offer details on the state of the injured, beyond that two people were flown out by helicopters and 13 others were transported by ambulance to Central Maine Medical Center and St. Mary's Regional Medical Center, both about 15 miles away in Lewiston. Jennifer Johnson, a nursing supervisor at St. Mary's, said her hospital had received seven patients -- all of them stable -- from the incident. Authorities remained on the scene Saturday night investigating the cause of the accident. In 2011: Police get 911 call from hayride . CNN's Greg Botelho contributed to this report.