You cannot reliably test for carbon monoxide without a detector
Use a certified carbon monoxide alarm or detector
Call your gas utility or fire department to check if you suspect a leak
Leave the area immediately if you suspect carbon monoxide exposure
Open doors and windows only if it is safe to do so while evacuating
Do not use appliances, switches, or flames if carbon monoxide is suspected
Check for symptoms such as headache, dizziness, nausea, weakness, confusion, or drowsiness
Inspect fuel-burning appliances for visible soot, yellow flames, or unusual behavior
Have chimneys, vents, furnaces, water heaters, and stoves professionally inspected
Never rely on smell, color, or taste to detect carbon monoxide