Ocean City, MD- Ocean City’s Fire Marshal’s Office says a gas-fired pool and spa water heater was the source of carbon monoxide that sickened a family of six at a hotel last week.

The family members became ill while staying in a first-floor room at the El Capitan hotel in the 400 block of Atlantic Avenue on June 11.

Investigators say the leak originated in the basement room where a Ray Pak 2100 gas-fired pool and spa water heater is kept. They say the heater was improperly vented and was the only carbon monoxide producing device in the building that could not be ruled out as a possible source.

The six family members were taken to Atlantic General Hospital, where they were treated and released