(Chemical formula: CO). A colorless, odorless, toxic gas formed by the incomplete combustion of carbon or carbon compounds. Carbon monoxide fumes may result from welding operations, and the welding operator must avoid breathing them. If natural ventilation is not adequate to remove the fumes, a suction system should be placed near the source to evacuate
them.
Molecular weight: 28.010. Specific gravity: 0.968 at 21°C (70°F). Critical temperature: -140.2″C (-220.4″F); critical pressure: 3499.2 kPa (507.5 psia). It condenses into a liquid which boils at -192°C (-314°F) and solidifies at -206°C (-339°F).