Whatever their nature, the fumes released while welding are classified since 1990 by the IARC (International Agency for Research on Cancer) as carcinogenic agents.
Dangerousness of the welding fumes
As the metal being weld is never absolutely clean, the fumes generated wile welding are dangerous and toxic. The presence of fats, paint or some fine particles produce highly carcinogenic agents such as formalin or polycyclic aromatic hydrocarbons (or polyaromatic hydrocarbons).
These fumes make out in two stages. The first one is the gaseous stage from the air decomposition (emergence of CO, CO2, ozone, nitrous vapors, etc.). The second one is the particle stage from welded metals releasing inhalable fumes and dusts but also from the electrode under the form of aluminium or chrome.
Protection against the welding fumes
In order to be protected against these carcinogenic agents, there are three different ways of respiratory protection according to the specificity of the welding activity :
The welding gas masks: Light and ergonomic, they offer a highly efficient filtering respiratory protection for occasional or short-term work. They are positive pressure devices, that means that the user is doing the breathing effort.
The powered air assisted respirators for welders: They are ideal for long-term work with their positive pressure system that injects breathable air into the hood. However, the use of these units needs an oxygen concentration rate superior to 19,5%.
The self-contained apparatus for welders : primarily used to work in confined spaces (sinks, holes, pits, crawl spaces, pipes, tanks, sewage…) when the atmosphere is non-breathable (when the oxygen concentration rate is below 19,5%). They are divided into two categories : the self-contained breathing apparatus and the airline devices. The first category is ideal for short-term works and the second category for long-term or tiring works.