Fairfield, CT — A five-story Fairfield apartment building was evacuated Monday night due to elevated carbon monoxide levels, according to a fire official.

Emergency personnel were notified of the issue about 8 p.m. when an alarm went off at the Trademark apartment building, 665 Commerce Drive, according to Assistant Chief Schuyler Sherwood. Carbon monoxide levels on the first floor were at 290 parts per million, Sherwood said. Firefighters determined a gas-powered machine being used for ongoing construction was the source of the problem.

First responders evacuated the building and ventilated it, according to Sherwood, who said no one was injured. The department was on site about two hours.