Flammable Limits in Air:  12.5-74% (by volume)
CAS # 630-08-0
NIOSH TWA 35 ppm
NIOSH Ceiling 200ppm
NIOSH TLV/IDLH 1200ppm
OSHA General Industry Standards  50ppm
OSHA Recommended Exposure Limit:  35 ppm 8 hr TWA

Carbon Monoxide is a flammable, colorless, tasteless and odorless gas which is toxic even in small quantities. Exposure to Carbon Monoxide decreases the ability of the blood to carry oxygen to the tissues. The more CO in the air and the longer you are exposed to it, the greater the danger. Higher concentrations may be rapidly fatal without producing significant warning symptoms. It is lighter than air. Carbon Monoxide is produced by the incomplete burning of any material containing carbon, such as gasoline, natural gas, oil, propane, coal or wood. Forges, blast furnaces and coke ovens all produce carbon monoxide.