This infographic demonstrates the level of severity during an indoor carbon monoxide leak. It is recommended that firefighters apply oxygen when levels hit 35ppm.

Carbon Monoxide is a colorless, odorless and dangerous gas (both toxic and flammable) formed by the incomplete combustion of carbon. It combines with hemoglobin more than 200 times faster than oxygen does, decreasing the blood’s ability to carry oxygen.

*Information gathered from “Essentials of Firefighters Edition 7” and GasLab.com