Last modified: Tuesday, July 15, 2008 2:35 AM EDT High carbon monoxide levels force family to flee Norton home BY MICHAEL GELBWASSER SUN CHRONICLE STAFF NORTON - Carbon monoxide levels in a West Main Street home were nearly five times higher than the safety threshold, forcing the residents and their dog to evacuate the house for more than an hour Monday. The incident, which occurred shortly before 10 a.m. at 247 West Main St., shows the need for carbon monoxide detectors throughout a house, fire Capt. Benton Keene III said. One of this home's detectors read 160 parts per million, Keene said. However, he said fire department readings in the basement "were even higher than that." Carbon monoxide levels in many homes average 3 parts per million, Keene said. Fire officials become concerned about safety when levels exceed 9 parts per million. Their detectors go off at 35 parts per million. The residents - a husband and wife and their son - were preparing to leave the house for the day when an upstairs detector activated, Keene said. They and their dog then went outside, where they called the fire department. Firefighters shut off the heating and ventilation, hot water and gas. The family's service contractors are investigating the incident, Keene said. Keene said it was good that the family went outside and took the dog, who would have been inside alone if they had just left. "In that environment, it would've affected them very quickly," Keene said.