Welding Fume Exposure

Welding Fumes


There is new scientific evidence from the International Agency for Research on Cancer that exposure to mild steel welding fume can cause lung cancer and possibly kidney cancer in humans. The Workplace Health Expert Committee has endorsed the reclassification of mild steel welding fume as a human carcinogen.


With immediate effect, there is a strengthening of HSE’s enforcement expectation for all welding fume, including mild steel welding; because general ventilation does not achieve the necessary control.


Control of the cancer risk will require suitable engineering controls for all welding activities indoors eg Local Exhaust Ventilation (LEV). Extraction will also control exposure to manganese, which is present in mild steel welding fume, which can cause neurological effects similar to Parkinson’s disease.

Where LEV alone does not adequately control exposure, it should be supplemented by adequate and suitable respiratory protective equipment (RPE) to protect against the residual fume.

Appropriate RPE should be provided for welding outdoors. You should ensure welders are suitably instructed and trained in the use of these controls.

Regardless of duration, HSE will no longer accept any welding undertaken without any suitable exposure control measures in place, as there is no known level of safe exposure.

Risk assessments should reflect the change in the expected control measures.

Action required

  1. Make sure exposure to any welding fume released is adequately controlled using engineering controls (typically LEV).
  2. Make sure suitable controls are provided for all welding activities, irrelevant of duration.  This includes welding outdoors.
  3. Where engineering controls alone cannot control exposure, then adequate and suitable RPE should be provided to control risk from any residual fume.
  4. Make sure all engineering controls are correctly used, suitably maintained and are subject to thorough examination and test where required.
  5. Make sure any RPE is subject to an RPE  programme. An RPE programme encapsulates all the elements of RPE use you need to ensure that your RPE is effective in protecting the wearer.

Further information can be obtained from the HSE website www.hse.gov.uk/welding/protect-your-workers/index.htm and COSHH Essentials WL3 can be downloaded from the HSE website publications

Extract from WL3

WL3 COSHH essentials for welding, hot work and allied processes

What this sheet covers

This sheet describes good control practice when using:

  • local exhaust ventilation (LEV) Control approach 2;
  • respiratory protective equipment (RPE) Control approach 2;
  • general ventilation Control approach 1.

It covers the key points you need to follow to reduce exposure to an adequate level for the following welding processes:

■ manual metal arc (MMA or stick) welding;

■ flux cored arc (FCA) welding;

■ metal inert gas (MIG) and metal active gas (MAG) welding;

■ gas welding;

■ tungsten inert gas (TIG) welding;

■ resistance spot welding.

Good control practice for welding fume

Frequency and duration of welding      Type of weldingGood control  practice
Sporadic low- intensity weldingGas, MMA, FCA, MIG, MAGLEV where reasonably practicable. Otherwise good general ventilation and RPE  
Regular and/or high intensity welding  Gas, MMA, FCA, MIG, MAG  LEV and consider supplementary RPE  
Regular and/or high intensity welding outdoors in the open airGas, MMA, FCA, MIG, MAG, TIG  RPE where LEV is not reasonably practicable  
Sporadic low-intensity welding  TIG and resistance spot welding  Good general ventilation  
Regular and/or high intensity welding  TIG and resistance spot welding  LEV  

Definitions used in above table:

  • High-intensity welding: repeated welding throughout the shift. Welding arc time of more than 1 hour per welder per shift
  • Low-intensity welding: welding lasting less than 1 hour per welder per shift
  • Regular welding: daily or weekly welding at any intensity
  • Sporadic welding: occasional welding carried out less than once per week which is incidental to the businesses core activity and cannot be planned for, eg. repair or maintenance work