SAFETY IN TIG WELDING-Gaseous and Metal Fumes HazardsThe major toxic gases associated in TIG welding are ozone, nitrogen dioxide and phosgene gas. Metal fumes are also produced during welding due to the vapourisation of alloying elements. Particular care is required about those elements producing toxic fumes. The ultraviolet rays emitted by the welding arc acts on the oxygen of the surrounding atmosphere to produce ozone. The inert gases used in TIG welding, though are not toxic in nature, can cause suffocation if accumulated in the breathing zone of the welding personnel.The toxic gas phosgene could be produced if chlorinated hydrocarbon cleaning agents, such as trichloroethylene, perchloroethylene and carbon tetrachloride are present near the welding arc. Hence these cleaning agents should not be used to clean the work piece or filler rod.A good ventilation in the welding area is required so that the concentration of these gases and fumes in the breathing zone of the welder remains well within the safe limit. If natural ventilation is not adequate, or the welding area is a confined area or if toxic metal fumes are produced, artificial ventilation systems like fume extractor should be provided.