Welding fuses two metal pieces together melting the base metal and a filler material forming a joint that is often stronger than the base metal. The heating of the base metal and filler causes vapors to emanate from the arc concentrating into extremely fine particles that can be exceedingly bad for human health. We have summarized some of the best practices for protecting yourself and others around you from the dangers of welding fumes.
What is in welding fumes?
Welding fumes occur when a metal’s temperature is elevated above its boiling point. When this occurs the metal’s vapors concentrate into solid particulates that are a combination of the metal being welded and the electrode. The resulting fumes are an intricate combination of silicates, fluorides and metallic oxides.
The composition of welding fumes can differ depending on the type of metal and flux being used.
- Welding stainless steel produces lower amounts of iron and a greater amount of nickel or hexavalent chromium.
- Mild steel welding fumes consists of mainly iron and trace amounts of metal additives like copper, titanium, cobalt, molybdenum, vanadium, hex chromium, manganese and nickel.
- Nickel alloys contains very scarce amounts of iron and has much more nickel.
- Fluxes made from fluoride or silica generates fluoride fumes, metallic silicates and amorphous silica.
Coatings Alter Welding Fume Content
- Welding galvanized steel produces zinc oxide fumes which if exposed to can cause metal fume fever which resembles common influenza producing symptoms like fever, chills, nausea, dizziness and achiness.
- Welding cadmium oxide plated metals creates a vapor that is extremely poisonous. The fumes have a considerable on the respiratory system and can cause inflammation of the mucous membranes, rawness of the throat and can cause fluid to build up in air sacs of the lungs. Long term exposure can result in death or permanent lung damage.
- Welding a surface that is coated with paint containing lead will give off fumes containing lead oxide. Breathing fumes that contain lead oxide can give you lead poisoning which causes anemia. Lead oxide also is harmful to kidneys, reproductive system and central nervous system.
Health Risks Associated With Breathing Welding Fumes
- Initial exposure to welding fumes can irritation to the throat nose and eyes and can cause nausea and lightheadedness.
- Being exposed to welding fumes over a long period of time can result in lung cancer, larynx cancer and urinary tract cancer.
- Certain types of fumes can cause damage to the central nervous system, kidney damage and stomach ulcers.
- Exposure to manganese fumes can cause symptoms similar to Parkinson’s Disease such as loss-of-balance, muscle rigidity, slowness of movement and tremors.
- Breathing of inert gases such as carbon dioxide, helium and argon in confined spaces can result in inert gas asphyxiation in which the gases displace the oxygen in the air causing the worker to suffocate.
Protect Yourself From Welding Fumes
- Coatings – The safest practice with coated steel is to remove the coating completely before welding so as to prevent the coating from becoming toxic vapors from the heat of the arc. This can usually be performed with an angle grinder and flap wheel.
- Welding Outdoors – Welders working outdoors should always position themselves so that they are working upwind of the arc so that the majority of the weld fumes will travel away from them.
- Welding Indoors – When proper natural ventilation is not possible local exhaust ventilation systems should be used to help clear the welder’s breathing from gases and fumes. To be sure that the greatest amount of fumes possible are being removed when using a local exhaust ventilation system make sure to keep the extractor guns and vacuum nozzles are as close to plume source as possible. Also, flexible exhaust systems can be used to draw the fumes away from the welder but always be sure that the ventilation is also aimed away from other workers as well.
- Confined Spaces – When welding in confined spaces always use sufficient mechanical ventilation or airline respirators and make sure to avoid blockage of ventilation equipment. If the ventilation equipment blocks passage to the space access to airline respirators and a standby worker has to be available.
- Respiratory Mask – Always be sure to wear respiratory protection if ventilation cannot reduce fume exposures to safe levels.
With some proper preparation and utilizing the safe practices highlighted here, injuries and death from welding fume inhalation can be greatly reduced if not eliminated. Always take the time to make sure you and you co-workers are safe from the dangers of welding fumes.