KINGSPORT, Tenn. (WJHL) — After a carbon monoxide leak in Kingsport Thursday evening, the Kingsport Fire Department is warning people of the dangers of the gas.

PREVIOUS STORY: Several taken to hospital due to carbon monoxide at Kingsport apartments

Seven people were hospitalized after a carbon monoxide leak in a Kingsport apartment complex.

Public Education Fire Officer Barry Brickey said that the building was evacuated then ventilated for hours before residents were allowed back inside.

“On scene they found out that a contractor was using a generator inside the basement to heat up some water,” Brickey said.

Brickey said to never use a generator inside a building and to typically put them at least 20-25 feet from the building outside.

“Carbon monoxide is an odorless gas that, in very low concentrations, can start giving you a headache,” Brickey said. “And when it gets to about 400 parts-per-million, you’re getting nauseous and you can actually pass out.”

Now the Kingsport Fire Department is warning the public of the dangers of the gas and how to prevent being the victims of a leak.

Brickey said he believes one resident in the complex had a carbon monoxide detector.

Officials advise always getting a carbon monoxide detector if you have anything that uses gas or creates heat inside and to make sure they’re well maintained.

“Whether it’s a carbon monoxide detector or a smoke alarm, you need to make sure it’s working properly, and if you have a smoke alarm that’s over 10 years old or a CO detector that’s over seven years old, you need new ones,” Brickey said.

Brickey said there could have been fatalities Thursday night, but luckily there were not.