Colombus, OH – An early morning furnace malfunction led to 11 people, including four children, being treated for carbon monoxide poisoning, Columbus Division of Fire Battalion Chief David Whiting said.

At approximately 7:35 a.m. Sunday, Dec. 13, firefighters were called to an apartment building at 1672 Shanley Drive in the Northland area, southeast of the intersection of Morse and Karl roads.

Some victims were treated at the scene, while others were transported to local hospitals for treatment before being released, he said.

Carbon monoxide is a colorless, odorless gas produced by burning material containing carbon. It is the leading cause of accidental poisoning deaths in America, claiming nearly 500 lives and causing more than 15,000 visits to hospital emergency departments annually, according to information from the Web site emedicinehealth.com.

Carbon monoxide poisoning can cause brain damage and death.

Early symptoms of carbon monoxide poisoning such as headaches, nausea, and fatigue, are often mistaken for the flu because the deadly gas goes undetected in a home. Prolonged exposure can lead to brain damage and even death.

Following clearance from fire and gas company officials, residents were allowed to return to their apartments.

Officials from Wentwood Breckenridge, owners and property managers of the building, declined to comment regarding a timetable to repair the furnace.

The Columbus Public Health Department shares these tips on its Web site for people to avoid carbon monoxide poisoning, which tends to be more prevalent during the winter months:

* Use a fireplace, wood stove or other combustion heater only if they are properly vented to the outside. Ensure adequate ventilation if you must use a space heater.

* Never use an electric generator indoors, inside the garage or near the air-intake of your house because of the risk of carbon monoxide poisoning. Never use a charcoal or gas grill inside — the fumes are deadly.

* Install a smoke detector and battery operated carbon monoxide detector. Check them frequently and replace the batteries as needed.