"It creeps up on you because carbon monoxide in general is hard to detect," said Christina Derinzo, a carbon monoxide education outreach coordinator.
If you can smell exhaust fumes, carbon monoxide is present, Derinzo said.
"They give you flu like symptoms if you’ve been exposed," Derinzo added. "Headache, dizziness, fatigue. People when they’re exposed sometimes don’t realize they are.