Welding, a major industrial process is concerned with joining metals by using a filler material. This filler material, known as the consumable is usually a coated electrode or wire. The process of melting this and the parent metal releases particulate fumes and gases, majority of which is produced from the consumable. The four most common welds are the tungsten inert gas (TIG), metal inert gas (MIG), metal active gas (MAG), and manual metal arc (MMA). (Pires et al, 2006)
Some of these emissions are toxic in nature which can prove hazardous on prolonged exposure. Presently, 1-2% of workers from different professional backgrounds (some 3 million persons) are subjected to welding fume and gas action (Pires, 1996). In confined spaces, welding can be deadly, as without proper ventilation, toxic fumes and gases can be much more intense, and possibly over the respective limits for toxic substances.
. In the recent years, occupational health hazards have formed the locus of intense academic study and research. The harmful effects of welding fumes have also been studied in great detail. The potency of the gas emissions depends on a number of factors like the nature of electrodes employed, the type of welding, filter metals, and also the ventilation facilities in the welding area. The emissions include metal oxide particles, gases, solvents, coatings and residues. Most of these are air borne and thus are constantly inhaled by workers.
Harmful Effects of different Metals Compounds
The welding fumes also contain compounds of metals like hexavalent chromium, nickel, manganese, zinc etc. It is difficult to find out the respective effects of different metals as most of tem are interrelated. (Hilton & Plumridge, 1991). But technological advancements have made it possible to draw a rough idea about each element's effect on the human body. It has been medically proven than nickel and chromium cause nausea, headaches, dizziness, thirst, fever, muscle ache, chest soreness and respiratory illnesses on short term exposure. Short term usually implies 12-24 hours, and these short term effects are generic for nearly all emissions. These effects also include gastrointestinal ailments, such as appetite loss, vomiting, cramps, and slow digestion. Nickel and Chromium fumes can also cause skin rashness and dermatitis. Nickel is also known to cause asthma, while chromium may cause sinusitis.
The chronic, long term effects of fumes containing nickel and chromium still remain ambiguous, but there are vague indications that they might be carcinogenic in nature i.e. they might act as cancer causing agents. The National Institute for Occupational Safety and Health has declared that some forms of hexavalent chromium, nickel and their inorganic compounds be considered carcinogenic.(American Welding Society, 2003) As a matter of fact, the long term effects of welding smoke in general remain disputes. Though there are reasons to believe that prolonged exposure might lead to immunosuppression, lung cancer development,