Residents of a Texas apartment building are recovering this morning after one person was found unconscious after being exposed to carbon monoxide.
12 patients in total were transported to hospital, the Houston Fire Department told ABC News.
Officials say the leak came from a boiler room attached to the building.
Exposure to the colorless, odorless gas can be extremely dangerous - as one couple from Oregon learned last week.
Kendra Platt and Steven Roberts were enjoying a quiet night at home, when Platt says she started to feel sick.
The next morning, she says she was still woozy, and then Roberts passed out.
“I knew something serious had happened, but not sure what” Roberts said.
“If I passed out we both would have been dead right now.” Platt added.
She managed to call 911, the audio of the call revealing the responding officers weren't certain of what caused the incident.
The couple were treated in a hyperbaric chamber to restore oxygen levels.
Carbon monoxide poisoning can be fatal. Symptoms include headaches, dizziness and vomiting.
Experts advise to have a working carbon monoxide detector in your home.
As of Sunday night, all the patients were OK, officials said.