SANFORD — A Clinton Street homeowner was treated at the scene for symptoms related to carbon monoxide poisoning, but did not require hospitalization after her furnace malfunctioned at about 7 a.m. today.

While carbon monoxide itself is a colorless, odorless gas, the malfunction ”“ or blow-back, as the furnace mishaps are commonly called ”“ caused the smell of sulfur and unburned fuel to fill the home, so the homeowner fled the building.

Sanford Fire Department Capt. Ron Grondin said carbon monoxide readings were around 80 parts per million, considered in the moderate range.

According to the Federal Environmental Protection Agency, the National Institute for Occupational Safety and Health has established a recommended exposure limit for carbon monoxide of 35 ppm.

Firefighters vented the home. Grondin said the homeowner will be able to return once the furnace is serviced.

Malfunctions are not uncommon, particularly in long, cold winters such as this one, said Grondin, as “furnaces have been working constantly.”

In Ogunquit Sunday, seven guests at the Falls at Ogunquit resort were treated at the hospital and 14 were treated with oxygen at the resort after a joint between two exhaust pipes separated, spreading carbon monoxide into 12 rooms.