Thousands of New York City subway riders were stranded for hours in Brooklyn in December 2024 after a transformer explosion occurred at an electrical substation where more than half of required safety checks had gone uncompleted, according to a report by the MTA inspector general.
The explosion at the State Street substation sent flames through a sidewalk grate and halted service on multiple lines, trapping over 4,000 passengers between stations for approximately two hours. The incident was later determined to have been caused by water leaking through split copper tubing within the transformer, mixing with synthetic oil and triggering the blast.
However, the MTA failed to investigate the root cause of the tubing failure, instead sending a carpenter to inspect the damaged equipment rather than an electrician with relevant expertise. The inspector general's report stated that the post-incident assessment was performed by personnel without electrical qualifications, and no expert examination ever took place. During the carpenter's inspection, the equipment was disassembled and subsequently left exposed to poor weather, destroying any possibility of determining the cause of the copper tubing failure.
The report, which audited New York City Transit's substation maintenance program, revealed broader systemic issues. Between April and the December explosion in 2024, 52% of required maintenance assignments at the State Street facility were not completed. These assignments are crucial for inspecting and maintaining the often decades-old equipment that powers the third rail.
Across the wider system, the audit found that 19% of all required maintenance assignments went unfinished systemwide in 2024. At all six substations visited that had fire alarm systems, control panels displayed "trouble" signals indicating malfunctions, but workers did not address them. The report noted that no MTA office or external company was tasked with monitoring these critical signals, and smoke sensors were not being maintained or tested.
Furthermore, inspectors observed that workers were not consistently using proper protective equipment for potential electrical surges, which can cause severe injuries or fatalities. The investigation also uncovered that the agency lacked a centralized system for tracking equipment defects.
In response to the findings, MTA announced a restructuring of its Power Division leadership to enhance oversight of maintenance practices and infrastructure upgrades. NYC Transit President Demetrius Crichlow stated that missed inspections of power substations are unacceptable.
The report did note an improvement in the systemwide maintenance completion rate in 2025, with uncompleted assignments dropping to 10%. However, at the State Street facility, 40% of scheduled assignments remained unfinished between April and November 2025.