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Written By: Robert E. Sheriff, MS, CIH, CSP, President
October 3, 2019
Welding Fumes Now Considered A Cancer-Causing Substance
The International Agency for Research on Cancer (IARC) has recently developed a monograph involving welding fumes (not just hexavalent chromium/stainless steel) where they state there is enough available evidence to classify welding fumes in general, as a cancer-causing agent.
It has long been known that welders seldom reach retirement age as a welder. Between problems in their cataracts, back, neck, and respiratory, acquired over a lengthy period of time as a welder, the potential for physical and health problems is high.
Several years ago, OSHA established a specific standard for exposure to hexavalent chromium (29CFR1910.1026-General Industry) and (29CFR1926.1126-Construction), which is a component of stainless steel and can cause cancer in humans. This latest IARC opinion covers all forms of welding fumes, not just hex chrome.
Control of worker exposure to welding fumes is difficult, at best, for a variety of reasons. There are different types of welding methods (MIG, TIG, STICK, TORCH, etc.) that use different strategies and different metals with a variety of potentials for exposure and overexposure to welding fumes. Also, just requiring a welder to wear a respirator adds a significant burden on the welder, who already is wearing a welding hood, possibly glasses, leathers, or other protective clothing and gloves in an environment that is also hot and gritty. Furthermore, just blowing air across the welding surface must be carefully controlled (usually minimized) to prevent interference with the inert gas shield at the welding point, which results in oxidation creating defective welds.
The primary objective of ventilation for the welding operation is to prevent the welding fumes from reaching the welder’s breathing zone but not extensive enough to interrupt the inert gas shield at the weld point.
There are several options: Blow the welding fumes away from the welder’s face with floor fans and general airflow, usually referred to as general ventilation. The problem is that those fumes just go into the building’s air and possibly affect others. The second option is local ventilation that is adequate to draw the welding fumes away from the welder’s breathing zone without interfering with the gas shield across the weld.
The use of “elephant trunk” exhausts near the work can be effective since the exhaust pick-up point can be moved to an acceptable point. On larger jobs, there are counterbalanced hoods or “elephant trunks” to deal with more mobile welding tasks.
There is no single solution to capturing welding fumes before they are inhaled by the welder. Each activity has to be addressed individually to determine if respiratory protection, local exhaust, or general ventilation are the appropriate measures needed. A final option is to try to separate the welder or equipment operator from the process. This can be done by 1) robotics, 2) isolating the welding process, or 3) isolating the welder/equipment operator from the welding process.
Even before recognizing the cancer-causing potential of all forms of welding, it has been recognized that COPD, more specifically chronic bronchitis, is a predictable condition of welders over a lengthy time period and metal fume fever from short-term intense weldings, such as inside a pipe, vessel, or container.
The addition of welding fumes as a suspect cancer-causing substance, greatly supports the need to evaluate a welder’s exposure to welding fumes, whether hexavalent chromium in stainless steel or collective metals and gases found in all forms of welding.
The appropriate method of evaluating a welder’s exposure to metal fumes is actually sampling the welder using portable sampling devices over the work period (usually a shift) to establish the level of exposure, especially where there is the potential for overexposure.
Generally, an Industrial Hygienist or Occupational Health Specialist is the appropriate person to do such an evaluation. This IH or OHS should have experience in performing such evaluations and knowledge of available corrective measures where overexposures are identified.
For information:
The exact wording of the IARC monograph is 4.5, Evaluation, (page 508),
“There is limited evidence in humans for the carcinogenic of welding fumes and gases.”
Overall Evaluation: “Welding Fumes are possibly carcinogenic to humans to humans (IARC Group 2B).”
This is a 687 page monograph that includes the detailed description of welding activities and the research data that suggests their opinion related to cancer causation, pages 447-527, “Chromium, Nickel and Welding,” IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 49—ISBN-13 (Print)-(978-92-832-1249-2) and ISBN-13 (pdf)-(978-92-832-1249-2) https://monographs.IARC.fr/monographs-available/
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