A Madison woman was transported to a local hospital Thursday afternoon after carbon monoxide levels reached 350 parts per million in her duplex, or seven times the minimum level of toxicity.
Madison firefighters and paramedics responded to 1027 Jana Ln. after a Madison Gas and Electric Company worker observed high levels of CO, Madison Fire Department spokesperson Lori Wirth said.
""For healthy adults, CO becomes toxic when it reaches a level higher than 50 parts per million with continuous exposure over an eight-hour period,"" Wirth said.
MGE crews arrived at the scene earlier after a resident reported a CO detector going off in his unit, according to Wirth. The crew found that the high reading of CO was in the neighboring unit.
Firefighters then assessed all the duplex residents, but only one person was taken to the hospital.
Crews then checked to make sure exhaust vents from the duplex were clear of snow and ice. MGE workers will check the furnace for any malfunction, Wirth said.
""In virtually every circumstance, the cause of the carbon monoxide buildup was snow and ice-covered furnace vents,"" Wirth said in a statement.
Firefighters previously responded to 11 carbon monoxide calls Wednesday. The calls began shortly after midnight, Wirth said.
The calls varied as some residents reported symptoms of dizziness or nausea and others were alerted by a carbon monoxide alarm.
Wirth advises homeowners to make sure chimneys and heating and dryer vents are clear of snow and ice to prevent a buildup of carbon monoxide.
—Maggie DeGroot
