The Thursday night explosion caused heavy damage to several floors of the John F. Kennedy High School in the Marble Hill section of the Bronx.
It wasn’t immediately known what triggered the explosion, but authorities said construction crews were working on a sixth floor gas line at the time. New York City Mayor Bill de Blasio said work was being done by private contractors to improve the school’s science labs.
The three workers were seriously burned.
The mayor said the Department of Buildings was investigating the structural integrity of the building.
The building housed eight schools for over 4,000 students, but de Blasio wasn’t sure if the damage would impact the start of school.
“If part of the building can be opened, if all of the building can be opened, we won’t know until that full assessment is done,” de Blasio said.
The first day of school is Sept. 9.
A 73-year-old man who lives across the street from the school told The New York Times he ran outside when he felt the force of the blast.
“The whole building shook for a very short time, like an earthquake,” said Eric Kumaga, adding that he saw no fire or smoke.