You’ve heard the expression, “You are what you eat.” Well, with welding, one could say you are what you breathe.
Welding smoke is a complex mixture of very small, condensed solids (fumes) and gases. The base and filler metals, fluxes, coatings, and shielding gases all contribute. Even chemical changes to the surrounding atmosphere from the intense radiation and heat can add to the mix.
The effects of welding smoke on a person will depend on the particular components of the smoke and how much of it the welder breathes. Some effects may occur shortly after exposure; these are acute effects. Long-term or chronic effects may not become apparent until after years of exposure.
Metal fume fever is the most common acute respiratory illness experienced by welders. It is a flu-like illness that lasts 24-to-48 hours. It is typically caused by exposure to zinc fumes, but copper, magnesium, and cadmium are also known to cause metal fume fever. Acute exposures to high concentrations of cadmium can be more serious though, producing severe lung irritation, pulmonary edema, or even death.
Long-term exposure to welding fumes may pose the risk of serious respiratory, nervous system, and reproductive effects, but more research is needed. Some metals we know are especially hazardous. These metals include lead, cadmium, beryllium, and mercury. But even welders who don’t work with these toxic materials may be at risk.
Carbon steel, which includes mild steel, is the most common material welded. The manganese in the steel and the filler metal sometimes results in overexposure to manganese. Chronic manganese poisoning can cause Parkinson’s-like disease and other neurological effects.
Stainless steel, high alloy steels, and nickel alloys expose workers to chromium and/or nickel fumes. Both nickel and hexavalent chromium are classified as human carcinogens.
Hazardous gases can also be produced during welding. Depending on the specifics of your process, these could include ozone, nitrogen dioxide, carbon monoxide, and fluorine compounds. These gases may cause both short and long-term effects.
To protect workers from welding fumes and gases, ventilation is often necessary, especially when welding with particularly hazardous materials or for long periods. It’s essential in enclosed or confined spaces. While air-purifying respirators can filter out metal fumes, they don’t protect workers from all of the hazardous gases produced or oxygen deficiency.