An explosion and fire tore through a shipyard on Staten Island on Monday afternoon, injuring at least 16 people and sending firefighters racing to a scene where workers had first been reported trapped. The blast hit 3075 Richmond Terrace, between Lockman Avenue and Andros Avenue, after crews were already trying to put out a fire in the back of the yard.

The FDNY said it received the call around 3:30 p.m. for workers trapped and a fire in a confined space near a dry dock. Around 4:20 p.m., officials said, a major explosion followed as firefighters were working to extinguish the blaze. One civilian believed to be a worker and two firefighters suffered serious injuries, two firefighters were listed in moderate condition, and nine firefighters and two EMS members had minor injuries. All were taken to area hospitals.

Richard Obiozor, who was nearby, said he saw a heavy emergency response before the blast. He said he saw a bunch of fire trucks and heard someone say every fire truck and police officer on the island was at the scene. A few minutes later, he said, a massive explosion sent a shock wave through the area and someone in a white suit, whom he believed was the captain, yelled for people to back up.

The fire began in a cramped area near a dry dock, where ships can rest on dry land, and officials said the cause of the fire and explosion was not yet clear. Police sources said a worker may still be unaccounted for, while several firefighters issued maydays during the battle with the blaze. Those firefighters were later located and were being treated, officials said.

Drivers were asked to stay away from the area as roads around the shipyard were closed for the emergency response. The immediate question now is whether every worker made it out, and investigators will have to piece together how a confined-space fire turned into an explosion powerful enough to injure firefighters who were already inside the response.