Carbon monoxide killed two people in a recording studio and sickened 12 others in a converted factory building in New Jersey, officials said.
Police responded to a 911 call Saturday at about 1:30 p.m. and found two dead on the second floor of the building in Passaic, Mayor Alex D. Blanco said during a news conference.
Twelve other occupants "experienced confusion and were choking" as they tried to leave the building, he said. They were being treated at three area hospitals.
Musician Daniel Flynn said he felt dizzy, but was able to leave the hospital after an hour. He said he was thankful a friend was able to dial 911.
"If he didn't make that call. ... Who knows?" he said. "I mean, I know the other musicians in there, two of them hit the floor while they were playing. They just dropped. The other was feeling faint. If he hadn't called, who knows what could have happened to them too."
Noel Korman, 39, and Alice Park, 29, died, police said Sunday. Both lived in Clifton.
The recording studio in which their bodies were found is one of several in the building.
"This is a sad day for the city of Passaic," the mayor said.
Technicians from PSE&G said the cause of the gas leak hasn't been determined. Gas has been shut off to six units in the building, they said.
Carbon monoxide typically leaks when a device isn't burning all of its fuel, said Karen Johnson, a spokesperson for the utility.
Carbon monoxide detectors are not required in that type of building, the mayor said.