Hazard versus Risk

A hazard is something that can cause harm and risk is a measure of the likelihood and consequence of the harm that is likely to eventuate. Consideration should then be given to risk controls that either eliminate or control the risk to a level that is reasonably practicable.

When the World Health Organisation (WHO) via the International Agency for Research on Cancer (IARC) classified Glyphosate as a probable carcinogen to humans, Group 2A, (IARC Monograph 112, 2015), the whole world was up in arms including many local governments here in Victoria. There was an immediate response to condemning the chemical and in some cases ceasing its use. The primary cancer was Non-Hodgkin Lymphoma (NHL), a lymphatic system cancer which can appear in many variations and is the group of lymphoma cancers that are the 6th most common cancer. NHL is not limited solely to Glyphosate exposure, unlike, for example, mesothelioma, which is predominantly as a result of exposure to Asbestos. (Mesothelioma in Australia 2015, 5th Annual Report)

When the WHO declared welding fumes as carcinogenic to humans Group 1, (IARC Monograph 118, 2018), there was a deafening silence to this significant change in hazard classification.  The report clearly states that welding fumes cause cancer of the lungs, the 5th most common cancer, and there is a positive association of cancer of the kidneys, the 9th most common cancer, in addition to ocular melanoma, which was declared in the 1990's. There was no knee-jerk response by councils or other organisations to stop all welding, especially on stainless steel.

In both cases, IARC uses a hazard based, weight of evidence assessment, rather than risk based, weight of evidence assessment. A hazard assessment considers the intrinsic toxicity potential of a chemical or work practice. This is not the same as a risk assessment, which takes into account the range of recommended controls to reduce the likelihood of a health effect from occurring as a result of the chemical's use or work practice.

In relation to Glyphosate, the Australian Pesticides and Veterinary Medicines Authority declared, in September 2018, that the product in its various forms is safe to use when the directions for use are followed. The directions include protecting hands from contact when diluting and using, protecting the respiratory system by using a range of spray techniques, use of respirators if deemed necessary and washing hands and other skin surfaces that may have come in contact with the product. It must be noted that some of the studies IARC reviewed that lead to their conclusion involved aerial spraying of Glyphosate which is not the method of application most people in the 'at risk' group such as grounds maintenance staff, farmers or members of the public employ when using the product.

For welding fumes, there are a limited number of publications that offer guidance as to how an employer can control exposure to the fumes. The only one I could find on WorkSafe's website was authored in 2011. It does state that inhaling fumes can cause lung disease and increase the risk of cancer. Fortunately, control measures for welding have continued to improve to address the risks, not the hazard, as that will always be present. The current control measures include automatic darkening helmets, Local Exhaust Ventilation systems and air fed welding helmets.  Given these control measures are already in place, I can only presume there wasn't a major outcry as many employers already had robust control measures in place.

The learnings from these two examples of organisational responses to the intrinsic potential occupational cancer hazard of substances is that we should pause, consider the risks by reviewing our existing control measures and work practices, and make changes when we believe the risk is not sufficiently reduced using the available body of knowledge.