(TNND) — An overnight fire in a Bronx public housing apartment killed an 11-year-old boy and left four of his relatives critically injured, after officials said a lithium-ion battery on an electric bike ignited and blocked the family’s escape.

The fire broke out just before 1 a.m. Wednesday on the 11th floor of the NYCHA Patterson Houses in Mott Haven. FDNY crews arrived within four minutes.

STRASSKIRCHEN, GERMANY - OCTOBER 01: Electric battery elements are seen during the launch event of the new BMW electric car batteries factory on October 01, 2026 in Irlbach-Strasskirchen, Germany.  The new plant will supply batteries to three electric car assembly plants with a production capacity of 3,300 cars per day. (Photo by Johannes Simon/Getty Images)

STRASSKIRCHEN, GERMANY – OCTOBER 01: Electric battery elements are seen during the launch event of the new BMW electric car batteries factory on October 01, 2026 in Irlbach-Strasskirchen, Germany. The new plant will supply batteries to three electric car assembly plants with a production capacity of 3,300 cars per day. (Photo by Johannes Simon/Getty Images)

Officials said the lithium-ion battery on an electric bike caught fire in the kitchen. The bike was blocking the apartment’s exit, making it difficult for residents to get out.

The boy died, and two teenagers and two adults in the family were critically hurt. The relatives suffered burns and smoke inhalation and were intubated.

Mayor Zohran Mamdani said no other units in the building required evacuation.

NEW YORK, NEW YORK - OCTOBER 13: Mayor Zohran Mamdani speaks during a ceremony at the NYPD Memorial Wall on October 13, 2026 in New York City. Mayor Mamdani was joined by New York Police Commissioner Jessica Tisch as added names of 42 fallen NYPD officers are unveiled at the memorial wall. The wall honors every NYPD officer who dies in the line of duty.  (Photo by Michael M. Santiago/Getty Images)

NEW YORK, NEW YORK – OCTOBER 13: Mayor Zohran Mamdani speaks during a ceremony at the NYPD Memorial Wall on October 13, 2026 in New York City. Mayor Mamdani was joined by New York Police Commissioner Jessica Tisch as added names of 42 fallen NYPD officers are unveiled at the memorial wall. The wall honors every NYPD officer who dies in the line of duty. (Photo by Michael M. Santiago/Getty Images)

FDNY Commissioner Lillian Bonsignore said lithium-ion batteries have sparked 401 fires in New York City this year, injuring 74 people, and killing six. Last year, officials reported 292 such fires, 51 injuries, and one death.

NYCHA CEO Lisa Bova-Hiatt said the housing authority’s rules allow one e-bike to be charged in an apartment, away from exits, while an adult is present and awake.

Mamdani and fire officials at a press conference Wednesday urged residents to use certified batteries, keep devices clear of exits, and charge them only while awake and present. They also encouraged storing devices outside living spaces when possible.