Sixteen people — most of them first-responders — were injured Friday afternoon when a vessel exploded at a dry dock in Staten Island, according to police and fire officials. The injuries include a civilian, 13 firefighters and two EMS workers.

The blast happened around 4 p.m. at 3075 Richmond Terrace, between Lockman and Andros avenues on the north shore of Staten Island, according to the FDNY.

The NYPD said two workers were painting the vessel when it exploded for unknown reasons. FDNY received the initial call just before 3:30 p.m., reporting workers trapped in a confined space in the dry dock, the department said. Crews found a fire in the basement of a 150-by-150-foot metal structure at the rear of the shipping docks. A second alarm was transmitted just after 4 p.m., and the major explosion followed 11 minutes later, according to FDNY.

One civilian was seriously injured, the FDNY said. Two firefighters were also seriously injured, two more firefighters sustained moderate injuries, and nine firefighters and two EMS workers were treated for minor injuries. All 16 were transported to area hospitals.

Firefighters were still actively working the incident Friday evening.

The city’s HazMat unit, the Department of Buildings and the Department of Environmental Protection had been notified, officials said.

The cause of the explosion remains under investigation.

This story is based on preliminary information from emergency officials and may be updated.