There are major safety concerns attached when welding galvanized steel. Galvanized refers to the coating of zinc on to steel. Zinc oxidizes to protect the steel near it which means, even if the galvanized steel surface is removed due to scrapping or scratching down to the bare steel, the galvanized coating will prevent rust from occurring.
1. Metal Fume Fever
When welding galvanized steel the zinc coating vaporizes and mixes with the air to form zinc oxide fumes. Studies have shown that this will not affect the health of the welder in the long-term, but does have a short-term effect. Welders will report similar symptoms to flu symptoms. The term for this is ‘metal fume fever.’ These effects go away within 48 hours of exposure. Research into this continues.
Metal fume fever often begins around three hours after exposure followed by a full recovery. Symptoms vary, but the list would include headaches, nausea, raised temperature, shivers and thirst. This means time off work for the employee and lost production for the employer. The answer is to significantly minimize or eliminate the inhaling of the zinc oxide fumes.
2. Long Term Health Concerns
The galvanized coating also has a small lead content. When welding galvanized steel this lead vaporizes and when mixed with air, forms lead oxide fumes. These fumes are dangerous and can lead to long-term health problems and should at all costs be avoided. The lead oxide fumes are only a tiny part of the total fume plume and the welder, when protected from the zinc oxide fumes, is also protected from the lead oxide fumes. When this article talks about ‘fumes’ it is referring to the fume plume which is a mixture of zinc and lead oxide.
3. Safety Gear and Proper Training
A major safety concern, connected with these fumes from welding galvanized steel, is lack of welder safety training. A welder needs to be trained to keep the welding shield, and therefore the welder’s face, out of the fumes. The welder needs to be positioned so that a clean airflow is maximized. This also stops oxidized dust from collecting inside the welder’s shield.
The welder should be concerned if the welder is not supplied with disposable masks and fully trained how to position them correctly. There must also be a published procedure available for inspection at the place of work. Painting masks can be effective but charcoal masks are better at trapping the particles in the fumes.
Another related safety concern is if the working environment is so fume filled that a mask is not adequate. Any symptoms reported while wearing a mask are a sign that this may be the case. If this is the case then the welder needs the added protection of a ‘personal environment system,’ which consists of a loose fitting welder’s helmet and a flexible cover that drapes down over the shoulders. The inside of the helmet is kept constantly filtered with compressed air, moved by small fans. This prevents fumes from entering the helmet and the welder then breathes only this clean, filtered, compressed air.
If the compressed air is not filtered when welding galvanized steel then the oil naturally occurring in this type of environment will quickly and irreversibly damage a welder’s lungs leading to death.