The Hidden Hazard of Field Welding

An engine driven welder makes welding possible almost anywhere—including
confined spaces, tanks, pits and underground drifts where ventilation is poor. The process produces
fumes containing metal oxides and gases that can harm the operator and nearby crew. Controlling fume
is not optional; it is a core part of safe field welding.

What Is in Welding Fume?

• Metal oxides: Iron, manganese, chromium and nickel from the electrode and base
  metal. Chromium (stainless) and manganese carry specific health risks.
• Gases: Ozone, nitrogen oxides, carbon monoxide (especially from engine exhaust
  near the work) and shielding-gas decomposition products.
• Process-dependent: Stick and FCAW generate more visible fume; stainless and
  hardfacing produce more chromium and alloy fume.
• Engine exhaust: The welder’s own engine emits CO and particulate—a
  serious hazard if the machine runs in or near an enclosed space.

Assess the Exposure First

• Where is the work? Open air, a pit, a tank, a drift or a building under
  construction all present different ventilation conditions.
• What process and consumable? Stainless, hardfacing and flux-cored are higher
  hazard than mild-steel Stick.
• How long and how many operators? Longer duty and multiple arcs multiply
  exposure.
• Where does the engine sit? Exhaust must never enter the breathing zone or a
  confined space.

Ventilation Strategies

• Natural ventilation: Adequate only for light work outdoors with good airflow.
  Never rely on it in confined spaces.
• Local exhaust ventilation (LEV): A fume-extraction nozzle at the arc captures
  most fume at the source. Best practice for shop and fixed field stations.
• Mechanical ventilation: Fans or blowers supplying fresh air and exhausting
  contaminated air. Use powered air movers with ducting for tanks and pits.
• Engine placement: Keep the engine driven welder outside the
  confined space, with exhaust directed away from intakes and work areas.

Respiratory Protection

• Disposable or half-mask respirators: Minimum for light fume; use P100 particulate
  filters and appropriate gas cartridges for the contaminants present.
• Powered air-purifying respirator (PAPR): Recommended for extended welding,
  stainless and hardfacing; it protects the breathing zone and combines with a welding helmet.
• Supplied-air respirator (SAR): Required when oxygen is deficient or contaminants
  exceed filter capability—common in tanks and confined spaces.
• Fit testing: Any tight-fitting respirator requires fit testing and a medical
  evaluation per your program.

Confined Space Program

• Test the atmosphere: Check oxygen, flammables and toxics before entry and
  continuously during work.
• Ventilate continuously: Supply fresh air and exhaust contaminated air; never
  weld in a sealed space.
• Attendant and rescue plan: A trained attendant must monitor; a rescue plan and
  equipment must be ready before entry.
• Hot-work permit: Coordinate with safety; control ignition sources and maintain a
  fire watch.

Conclusion

Fume control is as important as arc control when using an engine driven welder.
Assess the exposure, ventilate aggressively—especially in confined spaces—keep the engine
exhaust clear, and fit the crew with the right respiratory protection. Protect people, and the work
keeps moving safely. Explore our field welding safety equipment for a
better-protected crew.