The explosion happened shortly before noon inside Sky Island Lodge, a building on South Highland Avenue that houses the School of Business and Leadership, on the Rockland County campus. Fire officials say a small fire broke out, but the building's sprinkler system extinguished it.
Mike Donohue of Orange & Rockland Utilities says the elevated gas levels had been detected in the manholes around the Nyack College building. Officials say they assume that's what caused the blast.
The force of the explosion blew out windows and doors. One nearby resident heard the explosion, and said it was very loud.
There is extensive structural damage inside the building, according to officials. The building's basement and first floor have been severely damaged, with blown-out windows, staircases pushed aside and columns displaced.
Six employees and a female student were in the building at the time, the college said. They were taken to Nyack Hospital for treatment. One was later transferred to Westchester Medical Center for additional treatment. The others were released. The school sent out a tweet saying that "Everyone is doing ok."
For several hours after the explosion surrounding buildings were evacuated as a safety measure. Personnel were permitted to reenter the campus facilities after 2:30 p.m.
Nyack College is a Christian college about 25 miles north of New York City.
Students from Nyack Middle School were also evacuated to Nyack High School as a precaution after the explosion.