October 31, 2026 · Indumor
In the drawing: 1 welding fume, 2 local exhaust close to the arc, 3 arc radiation toward the helmet, 4 cylinder upright and chained, 5 work clamp next to the joint.
A July afternoon in the southern winter, with the doors shut against the cold, and the shop slowly fills up. First it is a bluish veil at the height of the lights. An hour later the veil has come down to face height and the lamps have halos. Nobody is coughing yet, and that is the problem: welding fume is made of particles far finer than a hair, which reach deep into the lungs. In 2017 the International Agency for Research on Cancer classified it as carcinogenic to humans, together with the ultraviolet radiation from the arc.
The first defense is to capture the fume where it starts. A hood or an extraction arm a few centimeters from the arc, or a fume-extraction gun, takes most of it before it rises; general ventilation in the building helps, but it arrives late. Then the station: the work clamp close to the joint and on clean metal, cables without cuts, cylinders upright with the valve protected and a chain holding them to the wall or the cart. Anything that can burn goes out of a radius of about ten meters (35 ft), because sparks can fly that far. And personal gear: a helmet with the filter shade the current calls for (for MIG-MAG, at least shade 10 from 60 A, with recommended shades running from 11 to 14 as current rises), leather gloves and jacket, and closed shoes. Screens around the station protect people walking by.
Your head stays out of the fume plume, to the side and not above the arc, and the hood moves with the work. Galvanized or painted parts give off zinc and other fumes that cause metal fume fever, so the area is cleaned or welded under extraction. Ozone formed by the arc light increases with argon-rich gases and with aluminum, which reflects a lot of radiation.
A tank, pit or chamber full of argon or CO₂ smells of nothing and can kill in minutes. Both gases are heavier than air, displace the oxygen and gather in the lowest spot. Working there takes oxygen monitoring, ventilation and someone standing outside. Never ventilate a confined space with oxygen: enriching the air turns clothing into fuel.
A MIG welder's voltage is low, but with wet clothes or standing in water it is not so low anymore. Cables are never wrapped around the body, and the work clamp never goes on the far side of a bearing or a chain, because the current would try to return through it.
The cylinder valve gets closed, the gun hangs off the floor, and the area gets another look a while later: an ember in a crack or in a rag can take time to catch. Hands get washed before eating, because shop dust carries metals.
In one sentence: fume gets captured at the arc and gas gets respect in enclosed spaces. If you need welded fabrication for your plant, Indumor can quote it: the form is further down. To keep going: shielding gases, where the shop's gases come from, welding galvanized steel and welding in our shop.
Think of the answer before you open it.
That it is carcinogenic to humans (Group 1), as is the ultraviolet radiation from welding.
Because it removes the fume where it starts, before it rises past the welder's face and spreads through the shop.
It is heavier than air, has no smell and displaces oxygen: it can asphyxiate without warning.
At least shade 10 from 60 A; the recommended shades run from 11 to 14, darker as the current goes up.
Structures and parts welded in our shop, to procedure when the job calls for it.
© Indumor 2010–2026 — Industrial steel fabrication, Córdoba, Argentina
