New York, NY — Two people are dead following a carbon monoxide incident at an apartment building in Brooklyn.

Two dozen residents of the building in Bensonhurst were stuck late Monday night trying to figure out where they were going to sleep after two of their neighbors died in an apparent poisoning in the building earlier in the evening, CBS2’s Jessica Layton reported.

Many of the residents said they had been feeling ill for days, and it looks like they now know why.

A 911 call brought first responders to 170 Avenue O, where two men were found unconscious inside the building. Authorities in hazmat gear quickly realized they were dealing with a carbon monoxide situation.

Four other people who live in the building said they felt sick. They were treated at the scene. Police said the men who died, ages 49 and 50, were found dead in the basement. A younger brother of one of the victims broke down as he explained how his brother was like a father to him.

Another resident said he and his girlfriend ended up in the hospital on Sunday, adding he thought he had COVID-19 at first.

“This is something that could have been avoided with carbon monoxide detectors. The detectors would have went off and they would have called 911 and it wouldn’t have come to this,” an FDNY official said.

Many of the people who live in the building said they think the carbon monoxide problem had been an issue for days. They said they felt nauseous and dizzy to the point of passing out.

City inspectors were expected to be on the scene all night. The displaced residents were said to be taken to hotels.