The East Haven Fire Department is reminding people about the dangers of carbon monoxide after a person was found dead from exposure Thursday.

Firefighters were called to a home on Salvatore Drive just after 2 p.m.

As they approached the front door, a carbon monoxide detector attached to fire department equipment bags activated, alerting personnel to dangerous levels of CO inside.

Officials say the readings in the home exceeded 500 parts per million in some locations, indicating an extremely hazardous environment. Firefighters had to leave the home and put on protective equipment before they could go back in.

Crews found an adult man dead in his bed.

Based on conditions, firefighters believe carbon monoxide exposure may have contributed to the person's death. The cause and manner will be determined by the Office of the Chief Medical Examiner.

Multiple officials confirmed that the source of the CO was a water heat that appeared to have been improperly installed. Investigators found a carbon monoxide detector inside the residence that did not contain a battery.

The department recommends residents take the following precautions:

The department says if an alarm goes off or you suspect exposure, it's best to leave the building, go outside and call 911. People should not go back inside until personnel determined it is safe to do so.