Welding fumes consist of gases and very fine airborne particles, known as particulate matter. They are produced when metals are heated above their melting point, and they contain a complex mixture of metal oxides as well as silicate and fluoride compounds. The exact composition depends on the individual welding method and the material being welded. 

Welding fumes are particularly dangerous because the majority of particles they contain are less than 0.1 micrometres in size and classified as “ultrafine." Once inhaled, ultrafine particles can travel dangerously deep into the lungs. They are so small they can also get into the bloodstream – enabling them to move to other organs, such as the brain, where they can cause immense damage. 

Welding fumes can cause asthma and many other health conditions. According to OSHA, prolonged exposure to welding fume may cause lung damage and various types of cancer, including lung, larynx and urinary tract. Other adverse health effects include metal fume fever, stomach ulcers, kidney damage nervous system damage, and even Parkinson’s–like symptoms.  

Because of this, OSHA has very strict regulations around welding fumes, and urges companies to use proper ventilation to limit the amount of particulate in the air. Failure to do so could result in OSHA violations, leading to fines or even legal action.  

About the new research 

The welding air quality studies were carried out by Zehnder Clean Air Solutions, a company specializing in the supply of air filtration systems to industry. It found pollution levels in the welding bays averaged 549 μg/m³, 10 times the amount you would find in America’s most polluted cities. Zehnder then measured the air quality in other parts of the factories, and the researchers couldn’t believe what they were seeing. 

“What we found was shocking,” says Zehnder’s Ben Simons, part of the team who carried out the study. “We were recording average levels that were twice as high as those at the welding stations themselves.”

Simons goes on to say: “You hear stories of welders cutting corners and not switching on their ventilation systems for a small job that won’t take long.  

“In these studies, we’re not talking about this kind of situation, dangerous though it is. On the contrary, our findings reveal that toxic fumes produced at a welding station can find their way to other parts of the factory, even when the exhaust and ventilation systems are running. 

“In other words, co-workers without any PPE could be unwittingly breathing in hazardous air pollution.” 

Zehnder has coined a term for this phenomenon: “pedestrianism." In a new whitepaper, the company explains its research methods in more detail, the dangers from welding fumes and what companies can do about them. It also outlines OSHA regulations designed to protect welders’ health, and what companies must do to remain compliant and avoid violations. 

But what about the pedestrians identified in the new research? Are OSHA regulations enough to protect them too? That question is one for employers and health and safety managers to think about. But if Zehnder’s findings are anything to go by, surely the answer is no.