One person died Friday after a fire and two explosions at a New York City shipyard injured dozens of people, officials said at a news conference. City and Fire Department officials said 36 people were hurt, most of them firefighters and other first responders, and one civilian died at the scene.

Fire Commissioner Lillian Bonsignore said multiple people called the fire department around 3:30 p.m., reporting smoke and two workers trapped in the basement of a 150-foot by 150-foot metal structure in the back of the shipyard. She said firefighting and emergency medical service crews were on the scene within six minutes.

John Esposito, the chief of department, said the first stage of the response focused on searching for the trapped workers. He said five firefighters and rescue paramedics were searching for the trapped workers inside and around the structure when a second blast happened, causing additional injuries.

Bonsignore said the explosion came shortly after crews arrived and included serious injuries to multiple fire department members and a couple of civilians. She said the most serious injuries occurred to a fire marshal and a firefighter who were inside the structure when the second explosion happened, as the blast’s shock wave hit them.

Esposito said confined spaces are especially dangerous for rescuers, describing them as “very dangerous operations for any rescuers.” He said the search effort placed firefighters and medics in the structure’s interior and adjacent areas before the second blast.

The fire marshal was in critical but stable condition with a fractured skull and a small brain bleed, Dr. David Prezant, the fire department’s chief medical officer, said. Prezant said medical staff would monitor him “very carefully over the next 24 hours to make certain there is not subsequent brain swelling,” adding that “as long as there is not, he should do well,” during Friday night’s briefing.

Prezant said the firefighter arrived at the hospital in serious condition but was “very well” by Friday evening, and that doctors would observe the person to ensure there were no muscle injuries. Mamdani said the fire was still burning but under control, and that more than 200 firefighters remained at the scene.

Mamdani said officials planned a comprehensive investigation into the cause of the fire “as soon as possible.” Outside the response area, witnesses described hearing explosions and feeling a shock wave, according to Richard Oviogor, who told WABC-TV that he heard two explosions.

The shipyard, officials said, is in an area with other businesses, including a coffee roasting company and a self-storage facility. The shipyard formerly belonged to Bethlehem Steel, which built ships for the U.S. Navy during World War II.