Welding Fume Exposure Monitoring – Sysco Environmental Ltd Case Study

How a Fabrication Site Controlled Welding Fume Exposure to Stay Well Below Safety Limits

Sysco Environmental Ltd conducted a workplace exposure assessment at a steel fabrication site in Cambridgeshire. In addition to paint-related hazards, the evaluation focused on welding fume exposure, especially during MIG and TIG welding operations on carbon steel and stainless steel components.

Personal air sampling was carried out on employees undertaking welding tasks in a large open-sided workshop. The primary goal was to evaluate the concentration of airborne metal particulates and determine if current control measures adequately protected workers from hazardous exposure.

Understanding Welding Fumes and Metal Additives

Why Metals Are Added to Steel

Steel alloys are formulated by introducing specific metals to enhance mechanical, thermal, and corrosion-resistant properties:

• Chromium improves hardness and corrosion resistance (main element in stainless steel).

• Nickel adds strength, toughness, and oxidation resistance.

• Manganese improves workability and hardness.

• Iron serves as the base metal but contributes to fume density during welding.

• Zinc, though not added directly, may be present from galvanised coatings and poses significant respiratory hazards when vaporised.

These metals become airborne as ultrafine particles and fumes during welding, creating a complex mix of potentially hazardous substances.

Health Effects of Common Welding Fume Metals

Metal	Purpose in Alloy	Primary Health Effect
Iron	Base material	Benign pneumoconiosis (siderosis), respiratory irritation
Manganese	Improves strength and hardness	Neurological effects (manganism – similar to Parkinson’s)
Chromium	Corrosion resistance (stainless steel)	Chromium VI: Carcinogenic, lung and nasal cancer risks
Nickel	Corrosion resistance, strength, oxidation stability	Respiratory sensitiser, lung cancer risk
Zinc	Found in galvanised coatings	Causes metal fume fever (flu-like symptoms)

Welding fumes are now classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC). Prolonged exposure may lead to chronic respiratory diseases and increased cancer risk.

Monitoring Methodology

Welding fume exposure monitoring was conducted in line with HSE guidance and MDHS 14/4. Personal samplers were worn by welders throughout their shift to evaluate time-weighted average exposure to inhalable metal particulates.

Key Sampling Parameters:

• Task: MIG/TIG welding of mild and stainless steel

• Sampling Time: 8-hour shift

• Equipment: IOM samplers with gravimetric analysis and ICP-OES for metal composition

• Metals Analysed: Iron, Chromium, Manganese, Nickel, Zinc

Monitoring Results

Substance	Exposure Level (mg/m³)	Workplace Exposure Limit (WEL)	Interpretation
Inhalable Dust	<0.11 mg/m³	10 mg/m³	Negligible; less than 1.1% of WEL
Iron	<0.11 mg/m³ (as dust)	5 mg/m³ (respirable)	Within safe limits
Manganese	<0.01 mg/m³	0.2 mg/m³ (inhalable)	Very low; less than 5% of WEL
Chromium	<0.004 mg/m³	0.5 mg/m³ (Cr III); 0.05 mg/m³ (Cr VI)	Well below WEL; not Cr VI-specific
Nickel	<0.003 mg/m³	0.1 mg/m³	Low exposure
Zinc	<0.01 mg/m³	5 mg/m³	Negligible

Conclusion: Welding fume exposure levels were well below occupational limits. However, continued vigilance is necessary due to the carcinogenic classification of some metals, particularly Nickel and Chromium VI.

Recommendations for Exposure Control

1. Local Exhaust Ventilation (LEV)

• Status: No fixed LEV system observed.

• Recommendation: Install or upgrade LEV (e.g. portable fume extraction units with hoods) to capture fumes at source and minimise spread in open workshops.

2. Respiratory Protective Equipment (RPE)

• Status: Disposable RPE used inconsistently.

• Recommendation: Introduce mandatory use of FFP3 masks or powered air-purifying respirators (PAPR) for prolonged welding. Provide face-fit testing and regular filter replacement schedules.

3. Health Surveillance

• Status: Not currently in place.

• Recommendation: Implement annual respiratory health checks for welders, particularly those working with stainless steel and galvanised components.

4. Training

• Status: Basic awareness provided.

• Recommendation: Deliver regular training on:

  • Specific health risks of metals in welding fumes

  • Proper RPE use and maintenance

  • Recognising early symptoms of respiratory illness

Conclusion

Sysco Environmental Ltd’s assessment confirmed that welding fume exposure at the Cambridgeshire fabrication site was within safe limits, but identified opportunities for proactive improvement. Given the toxic and carcinogenic nature of key metals in welding fumes, a precautionary approach is vital.

By reinforcing ventilation, enforcing consistent RPE use, and training staff on fume hazards, the facility can continue to protect workers and meet COSHH obligations.