BOHS Technical Guide – Monitoring Exposure to Welding Fume
Monitoring Exposure to Welding Fume
This BOHS technical guidance document provides practical advice on assessing and monitoring worker exposure to welding fume. It explains the hazards associated with welding operations, the contaminants commonly present within welding fume and the methodologies available for measuring worker exposure.
The guide recognises that welding fume is a complex mixture of airborne contaminants containing fine and ultrafine particles, metal oxides and gases. Exposure has been linked to a range of adverse health effects including occupational asthma, metal fume fever, chronic respiratory disease, neurological effects and cancer.
The document provides guidance on:
- Personal exposure monitoring
- Sampling strategies
- Selection of sampling equipment
- Measurement of welding fume constituents
- Exposure assessment methodologies
- Workplace Exposure Limits (WELs)
- Interpretation of monitoring results
- Control verification
- Occupational hygiene best practice
This resource is relevant to:
- Occupational Hygienists
- LEV Designers
- LEV Consultants
- P601 TExT Engineers
- Welding Engineers
- Health & Safety Professionals
- Duty Holders
- Exposure Monitoring Specialists
- Manufacturing Managers
Source Document
View the BOHS Technical Guide here:
Source: British Occupational Hygiene Society (BOHS)
Document Type: Technical Guidance
Status: Current
Last reviewed by LEVCentral: June 2026
LEVCentral Expert Commentary
This document is particularly valuable because it addresses a question frequently asked by both duty holders and LEV professionals:
“How do we know our welding fume controls are actually working?”
While LEV commissioning and TExT activities provide evidence that ventilation systems are functioning as intended, occupational exposure monitoring remains one of the most direct methods of assessing whether workers are adequately protected.
The guidance explains that welding fume is not a single contaminant but a complex mixture that varies according to:
- Welding process
- Parent metal
- Consumables
- Shielding gases
- Process parameters
- Workplace conditions
As a result, exposure assessments should focus on the specific hazards generated within the workplace rather than treating all welding operations identically.
The document is particularly relevant following HSE’s 2019 enforcement changes, which recognised all welding fume, including mild steel welding fume, as carcinogenic and requiring suitable engineering controls.
For LEV practitioners, the guide reinforces several important principles:
- Effective LEV should minimise worker exposure rather than simply move contaminants around the workplace.
- Airflow measurements alone do not demonstrate exposure control.
- Personal exposure monitoring can provide valuable evidence supporting commissioning and TExT findings.
- Monitoring results should be interpreted alongside observations of work practices, LEV performance and management controls.
- Welding fume control requires a combination of engineering controls, supervision, training and maintenance.
One of the strongest messages within the document is that exposure monitoring should not be viewed solely as a compliance exercise. Instead, it should form part of a wider programme of continuous improvement and occupational health protection.
For organisations operating welding processes, the guide provides a useful framework for integrating occupational hygiene monitoring with LEV management systems and health surveillance programmes.
Further Resources
- HSE Welding Fume Enforcement Guidance
- HSG258 – Controlling Airborne Contaminants at Work
- RR683 – Effective Control of Gas Shielded Arc Welding Fume
- BOHS Breathe Freely Welding Fume Control Selector Tool
- HSE COSHH Essentials – Welding
