Emergency responders say marijuana grow houses that could be built in New York City are not just bad for the community -- they could also be deadly.

Former DEA Special Agent in Charge James Hunt referenced explosions like the one in Kingsbridge that killed Battalion Chief Michael Fahy in 2016. The blast injured dozens.

Hunt says the DEA deals with two or three cases each year relating to grow houses. But he adds that when they are in the city, things change.

"You see a fireman got killed, another hurt recently. They don't know what they are going into. They think they're saving someone from a fire. You go inside, you have all these chemicals around. You aren't prepared to go into this," says Hunt.

Another grow house incident happened in Pelham Bay this October. Firefighter Thomas Corcoran injured his leg and back after falling off a ladder.

Hunt says there are a few different ways grow houses become hazards.

"They have to cut into electrical systems' wires a lot of times. They don't have real electricians do this, they're doing it themselves."

Hunt says they are also pumping carbon dioxide into small apartments while handling fertilizers, which is flammable.

Investigators say signs of a grow house include blacked-out windows and excessive electricity and water usage.