MIG and MAG Welding Safety

MIG (Metal Inert Gas) and MAG (Metal Active Gas) welding use a continuously fed wire electrode and shielding gas to join metals.
MIG/MAG is the most widely used welding process on construction sites due to its speed, versatility, and ease of use.
Welding fume from MIG/MAG processes is classified as a human carcinogen — local exhaust ventilation is mandatory.
The shielding gas (argon, CO2, or mixtures) displaces oxygen in enclosed spaces, creating an asphyxiation hazard.
The welding arc produces intense UV radiation that causes arc eye and skin burns to the welder and nearby workers.
Spatter from MIG/MAG welding consists of molten metal droplets that cause burns and ignite combustible materials.
Wire feed mechanisms create entanglement and finger-trap hazards during spool changes and wire straightening.
Electrical shock from the welding circuit is a risk, particularly in damp conditions or when cables are damaged.
A hot works permit is required for all MIG/MAG welding on construction sites to manage the fire risk from spatter.
Welders must hold a valid qualification for the MIG/MAG process and the material being welded.

Carcinogenic fume	MIG/MAG welding fume is confirmed as a human carcinogen since 2019 — on-tool extraction or LEV is legally required for every weld.
Shielding gas asphyxiation	Argon and CO2 shielding gases are heavier than air and displace oxygen in pits, tanks, and enclosed spaces without warning.
UV radiation	The MIG/MAG arc produces extremely intense UV that causes painful arc eye within seconds of unprotected exposure.

Do

Don't

Use on-tool fume extraction or LEV for every MIG/MAG welding operation.
Ventilate enclosed spaces to prevent shielding gas accumulating and displacing oxygen.
Wear an auto-darkening helmet with the correct shade for MIG/MAG welding.
Wear flame-resistant clothing, leather gauntlets, and safety boots during welding.
Erect welding screens to protect nearby workers from UV radiation and spatter.
Obtain a hot works permit before starting MIG/MAG welding on the construction site.
Check the welding machine, cables, torch, and earth connection before each shift.
Keep hands clear of the wire feed mechanism during spool changes.
Hold a valid welder qualification for the MIG/MAG process and material type.
Maintain a fire watch during and for 60 minutes after MIG/MAG welding.

DON'T weld with MIG/MAG without fume extraction — the fume is a confirmed carcinogen.
DON'T weld in enclosed spaces without monitoring oxygen levels and providing ventilation.
DON'T look at the arc without the correct welding lens shade for MIG/MAG.
DON'T weld without flame-resistant clothing — spatter burns through standard workwear.
DON'T allow unprotected workers near the welding arc — UV causes injury in seconds.
DON'T start MIG/MAG welding without a valid hot works permit in place.
DON'T use equipment with damaged cables, a faulty torch, or poor earth connections.
DON'T reach into the wire feed mechanism while the machine is powered on.
DON'T carry out MIG/MAG welding without the correct qualification for the process.
DON'T leave the area unwatched after welding — fires start from spatter hours later.

See also: Welding Safety Awareness (Comprehensive) | Welding Fume Extraction & LEV

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