MONROE, N.Y. — A bungalow suddenly burst into flames at a camp in upstate New York, sending four 18-year-old students from a Brooklyn yeshiva to the hospital with burns, a school official said Friday.

Firefighters from eight departments battled the blaze that broke out shortly after midnight Friday at Quaker Hill Cottages in Monroe, New York, about 45 miles (70 kilometers) north of New York City.

A 12th-grade class from Yeshivas Novominsk had just arrived at the bungalow for a weekend graduation trip, said Rabbi Lipa Brennan, the school's executive director

"They were literally walking into the bungalow. They smelled a gas leak or some gas, and a second later it just went up," Brennan said.

The rabbi said the four hospitalized students with various degrees of burns are expected to recover. Emergency officials overnight had described several injuries as serious. The hospitalized teens' conditions were not immediately available Friday.

Eight other students with minor injuries returned home with the rest of the class, Brennan said.

Orange County Emergency officials say it took about 40 minutes to extinguish the flames. They were trying to confirm whether gas is to blame for the explosion.

"This area does not have fire hydrants, so they had to set up a remote water supply," Vini Tankasali, the county's deputy commissioner for fire services, told the Times Herald-Record of Middletown.

The upstate fire happened hours after a school bus from another Brooklyn yeshiva overturned on a ramp near a bridge connecting New Jersey and New York City. Minor injuries were reported after bus tipped at about 4 p.m. Thursday on the New Jersey Turnpike near the Goethals Bridge.