Officials said an explosion occurred during the science experiment in a chemistry class at Beacon High School around 9:00 Thursday morning.
One 10th grade student suffered burns to the face and neck. Another suffered burns on the hands.
Both were taken to the Cornell burn unit at New York Presbyterian Hospital.
The Fire Department says one student is in serious condition and the other suffered minor injuries.
Parents have been notified, authorities said.
The principal is investigating the incident.
The accident happened on the first day of school after the holiday break.