EAST TREMONT, the Bronx (PIX11) — Two people were in serious condition after a carbon monoxide leak at a Bronx building Wednesday morning, sources said.

The carbon monoxide alarm went off at around 6:45 a.m. at the Twin Park South East building at 800 East 180th St. in East Tremont, according to the FDNY. At least 13 residents, including a 17-year-old, were taken to the hospital for carbon monoxide poisoning, authorities said. Two of the patients were in serious condition, sources said.

The building was evacuated before residents were allowed back at around 8:40 a.m., officials said.

The New York City Department of Buildings said an old corroded gas boiler sent carbon monoxide into the trash compactor room, which is how carbon monoxide spread through the building.

Esmeralda Ramos, a mother who lives in the building, spoke to PIX11 News about the experience.

“An alarm started going off, so I automatically jumped up. When I walked out of the room, it hit me. I started feeling dizzy. I was like what’s going on,” Ramos said.

Ramos said she had no time to think. She had to wake up her children and get them out of their sixth-floor apartment.

“I was crying, I was scared, I was praying that they were OK, that they were going to wake up,” Ramos said. “I was banging on their doors trying to get them up. At the same time waking them up, I was on the phone with 911.”

Once outside, Ramos realized there was a carbon monoxide leak. All of the residents of the building had to be evacuated. Ramos and her children were among the residents who were taken to a hospital.

Inspectors with the Department of Buildings, the FDNY and the NYPD responded to the scene.