MIG Welding Gas Side Effects and How I Follow Safety Before MIG Welding
The first time I experienced metal fume fever, I did not know what was happening to me. It was a Monday morning in the fabrication shop. I had spent the previous Friday afternoon welding on some galvanized steel brackets without proper ventilation. By Sunday evening I had chills, body ache, and a mild fever. I thought it was a normal flu. Monday when I came to work and told my foreman, he immediately asked what I had been welding on Friday. When I said galvanized, he shook his head and said — "That is not flu. That is zinc poisoning from the fumes. You were lucky it was mild."
That incident changed how seriously I take MIG welding gas safety. Before that day I treated fume safety as something the safety officer talks about in induction training and then everyone forgets. After that day it became a real personal habit that I follow on every job.
Gases and Fumes Does MIG Welding Produce in work
Welding fume is a complex mixture of airborne gases and fine particles generated during the welding process. In MIG welding specifically, the fumes come from three sources — the base metal vaporising under heat, the wire electrode burning off, and the shielding gas reacting with the arc.
The chemical content of MIG welding fumes depends on the material you are welding. This is something most beginners do not realise. Mild steel fumes are different from stainless steel fumes. Galvanized steel fumes are different again. And aluminium fumes have their own specific health risks.
Iron oxide fumes are produced in almost every MIG welding on mild steel and carbon steel job. Continuous long-term exposure causes respiratory irritation, lung inflammation, and over many years increases the risk of chronic lung disease.
Manganese fumes are present in most MIG wire compositions including standard ER70S-6 carbon steel wire. Manganese, commonly present in MIG welding fumes, is known to cross the blood-brain barrier and may result in manganism, a neurodegenerative disease similar to Parkinson's. Symptoms include tremors, difficulty walking, and facial spasms. This is serious. I had never heard about manganism until a senior welder on one of my Gulf projects mentioned it. From that point I started using a proper respirator on every indoor welding job.
Zinc oxide fumes come from welding galvanized steel. This is the cause of metal fume fever — the flu-like reaction I experienced personally. MIG welding with galvanized steel vaporizes the zinc coating, producing toxic zinc oxide fumes leading to metal fume fever, with symptoms such as chills, fever, and muscle aches.
Hexavalent chromium fumes are produced when MIG welding stainless steel. Prolonged exposure to chromium and nickel fumes can lead to severe respiratory conditions and lung cancer. Stainless steel welding fumes are classified as carcinogenic. On every stainless steel job I have ever worked, the safety briefing specifically covered chromium fume exposure and the PPE requirements were stricter than mild steel work. For stainless steel wire grades and which materials produce the highest fume risk, our guide on MIG Welding Best Wire Coil for SS and CS Job explains the material differences in detail.
Ozone gas is produced when the UV radiation from the welding arc reacts with oxygen in the surrounding air. Short-term effects include eye, nose, throat, and lung irritation, headaches, and temporarily reduced lung function. Long-term health impacts of ozone exposure include asthma and chronic lung disease. Aluminium MIG welding produces particularly high ozone levels. For full details on aluminium MIG welding precautions, read our guide on MIG Welding Aluminium.
Short-Term Side Effects of MIG Welding Gas
These are effects that happen quickly, sometimes within hours of exposure.
Gases and fine particles in welding fume can cause dryness of the throat, coughing or tightness in the chest. The effects tend to be short-lived.
From my own experience and from what colleagues have shared, the most common short-term effects include:
- Throat and nose irritation after indoor welding sessions
- Headache after extended welding in enclosed areas
- Eye irritation from arc UV radiation and fume particles
- Metal fume fever after galvanized or zinc-coated material welding
- Dizziness when welding in confined spaces with inadequate ventilation
Many welders get flu-like symptoms after welding. Metal fume fever is usually linked to welding or hot work on galvanised metals. It often starts a few hours after exposure begins and carries on for a while after exposure ends.
My foreman always said — if you go home with a headache after a welding shift, something was wrong with your ventilation setup. Headache is the first signal your body gives you.
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Long-Term Side Effects of MIG Welding Gas
These are the effects that develop over years of continuous exposure without proper protection. They are more serious and unfortunately they develop slowly so many welders do not connect them to their welding work until the damage is significant.
Both acute and chronic health risks are associated with welding fume. Occupational lung disease, including lung cancer, is the most common health risk, but welding can also affect the eyes and skin. There is also a significant risk from asphyxiation when welding in confined spaces.
Welding fumes are linked to bronchitis, respiratory irritation, and inflammation. Exposure to metal oxides including manganese and nickel has been linked to serious health risks.
The welders I have seen suffer the most from long-term fume effects are those who spent years doing indoor welding in poorly ventilated workshops without any respiratory protection. They treated the smoke as normal. By the time chronic breathing problems appeared, years of fume exposure had already done real damage.
MIG Welding Gas and Fume Risk Table
| Material Being Welded | Main Fume Risk | Health Effect |
|---|---|---|
| Mild steel, carbon steel | Iron oxide, manganese | Respiratory irritation, manganism risk with long exposure |
| Galvanized steel | Zinc oxide | Metal fume fever, chills, fever, muscle ache |
| Stainless steel | Hexavalent chromium, nickel | Lung cancer risk, severe respiratory conditions |
| Aluminium | Ozone, aluminium oxide | Throat and lung irritation, chronic lung disease |
| Coated or painted metal | Variable toxic compounds | Depends on coating type, can be highly harmful |
How I Follow Safety Before Starting MIG Welding
Over years of fabrication and site work, I have developed a fixed personal safety routine that I follow before every welding session. These are not theoretical rules. These are habits I built from real experiences and from corrections my supervisors and safety officers gave me on different projects.
Check ventilation first. Before I pick up the welding torch, I check the airflow in my working area. For indoor shop welding, I confirm the extraction fan is working or position a portable fume extractor close to the weld zone. For enclosed area work, I follow the site confined space procedure and never weld without confirmed air supply.
My supervisor on a Saudi shutdown project told me once — "You can replace a welding machine, you can replace a wire spool, but you cannot replace your lungs." I never forgot that.
Wear the right respirator. A standard dust mask is not sufficient for MIG welding fumes. I use a half-face respirator with the correct filter cartridge rated for metal fumes and organic vapors. On stainless steel jobs specifically, I upgrade to a P100 particulate filter to handle hexavalent chromium particles.
Inspect my helmet and lens shade. UV radiation from the welding arc causes arc eye — a painful condition similar to a sunburn on the cornea. I always check that my auto-darkening helmet is functioning correctly and the lens shade is appropriate for my amperage range. For standard MIG welding, shade 10 to 12 is the typical requirement.
Check shielding gas connections. A leaking gas hose does not just affect weld quality. At high flow rates, concentrated shielding gas including CO2 and Argon can displace oxygen in enclosed areas and create an asphyxiation risk. I check all hose connections and the regulator reading before starting any welding session.
Identify the base metal coating. Before welding any material, I check if it is painted, galvanized, zinc-coated, or has any surface treatment. Welding over coatings without removing them or knowing what they contain is one of the most avoidable fume hazards in the fabrication shop. I grind or degrease the weld area before striking the arc.
For correct MIG welding machine settings including voltage and wire speed that help control heat input and reduce fume generation, our complete reference is at MIG Welding Settings – Voltage and Wire Speed.
PPE Checklist Before MIG Welding
| PPE Item | Purpose | Minimum Standard |
|---|---|---|
| Auto-darkening welding helmet | Arc UV and IR radiation protection | Shade 10 to 12 for MIG |
| Half-face respirator with metal fume filter | Fume and particle inhalation protection | P100 for stainless, OV/P100 for galvanized |
| Leather welding gloves | Spatter and heat burn protection | Full gauntlet type |
| Flame-resistant welding jacket | Spatter and UV skin exposure | FR cotton or leather |
| Safety boots | Spatter and falling object protection | Steel toe, ankle coverage |
| Ear protection | Grinding and fabrication noise | When ambient noise is above safe level |
FAQ
Q: What are the main side effects of MIG welding gas and fumes? Short-term effects include throat irritation, headache, eye irritation, and metal fume fever. Long-term effects from chronic unprotected exposure include respiratory disease, lung cancer risk, and manganism from manganese fume accumulation.
Q: Is MIG welding fume harmful for mild steel? Yes. Mild steel MIG welding produces iron oxide and manganese fumes. Long-term unprotected exposure causes respiratory problems and manganese-related neurological effects. Proper ventilation and respiratory protection are required even for standard steel welding.
Q: What causes metal fume fever in welding? Metal fume fever is caused by inhaling zinc oxide fumes produced when welding galvanized or zinc-coated steel. Symptoms include chills, fever, and body ache, typically starting a few hours after exposure.
Q: What respirator should I use for MIG welding? A half-face respirator with P100 particulate filters is appropriate for most MIG welding work. For stainless steel, use combined OV/P100 cartridges to protect against hexavalent chromium particles. A standard dust mask does not provide adequate protection.
Q: How do I reduce MIG welding fume exposure on site? Position yourself upwind or use local exhaust ventilation close to the weld zone. Use the lowest practical voltage and wire speed to reduce fume generation. Always remove coatings from the weld area before starting. In enclosed spaces, follow confined space procedures with confirmed air supply.
Conclusion
MIG welding gas and fume side effects are real, they are well documented, and they are completely preventable with the right habits. Metal fume fever, respiratory irritation, and long-term lung disease are not inevitable parts of a welding career. They are the result of not taking fume protection seriously.
My own metal fume fever episode early in my career was a direct consequence of ignoring ventilation on a galvanized steel job. After that experience I never started a welding session without checking my ventilation setup and wearing proper respiratory protection. Fifteen years later my lungs are fine and I plan to keep them that way.
Take fume safety as seriously as you take your welding technique. Your career depends on your skills but your health depends on your safety habits. Both matter equally.
Santoshsingha
Mig Welder , Good experience in Welding industry last 10 years I worked in multiple countries like USA, Canada, India, Australia and Russia.
