Three contractors were injured in an explosion of a gas line at a construction site in a high school in Marble Hill. Crews were working on the line on an upper floor at Kennedy Campus when one worker lit a match to test the gas line, causing the blast Thursday night, investigators said.
The injured are being treated at Jacobi Hospital and are expected to recover.
Gas to the building had been shut off.
More than 100 firefighters responded to the campus on Terrace View Avenue just after 8 p.m.
Fifteen people were in the building at the time of the explosion.
First responders searched in and around the school for anyone trapped or hurt.
A custodian told Fox 5 that he heard a loud blast and felt a shake.
The explosion was possibly related to natural gas. An official said contractors were working on a nearby gas line. Con Edison dispatched a crew to investigate and has shut down gas to the building.
The city's Office of Emergency Management said the explosion appeared to damage the fifth and sixth floors.
OEM also said motorists can expect traffic delays in the area of Terrace Avenue and Johnson Avenue because of street closures and emergency vehicles.
The Kennedy Campus houses seven specialty schools.
"In the coming weeks we will do everything we can to make sure that John F. Kennedy High School Campus is safe and ready to open for students," said State Assemblyman Jeffrey Dinowitz.
The Department of Buildings has issued a vacate order on the entire building. Safety zones are in place along the south and west facades.
Marble Hill is a small neighborhood geographically part of the Bronx but legally part of Manhattan. The Bronx-Manhattan border actually cuts through various residential and other properties.