Is Glyphosate carcinogenic or not?
Updated: Apr 2, 2020
I recently read the attached article while doing a little exploration for a client using a commonly used herbicide 'Round Up'. The query was prompted by a client that used it to manage unwanted vegetation, where vegetation management is not their core line of work. So of course as a diligent professional I asked my client if they had a risk assessment for using the product. They didn't.
"It's just Round Up" they said confidently,
"Everybody uses it." Round Up is a popular, readily available brand of herbicide that uses Glyphosate. Glyphosate is used in many chemical herbicides globally.
In my memory banks I thought I'd read that IARC (International Agency for Research on Cancer) had reclassified Glyphosate as a probable carcinogen. I wanted to know if the client has reviewed its use in response to the IARC classification. The client did not know about it. So I started searching.
They had an updated Safety Data Sheet (SDS) published in 2016 (which according to common practice is current), the IARC classification was not listed. The available monograph published for Glyphosate (http://publications.iarc.fr/549) was updated in August 2016 and indicates it is a class 2A Carcinogen - probably carcinogenic to humans. Meaning, roughly, that evidence of changes to cells can be created in a laboratory setting, but as yet there insufficient evidence in the human population to link Glyphosate to cancer.
I went to Google. I googled a couple of different suppliers to see if they had newer data sheets. Nope still 2016. Then I found the article...describing how two significant international authorities, the US EPA and IARC have opposing views on the classification of the substance. How does this happen? More importantly how does the regular employer keep their head above all of this information? The crux of the matter from what I can determine is that these two organisations have a different focus. One on public health (EPA), and the other (IARC) on wider health implications including occupational health exposures. As an OHS professional of course I'm interested in the occupational exposures.
So what is the Australian position on Glyphosate? Quick answer is... there isn't one! The ADOPTED NATIONAL EXPOSURE STANDARDS FOR ATMOSPHERIC CONTAMINANTS IN THE OCCUPATIONAL ENVIRONMENT [NOHSC:1003(1995)] hasn't been reviewed in twenty-five years! It is up to your supplier/manufacturer of the chemicals to keep you informed through their Safety Data Sheet. It is up to them to be diligent in understanding the health risks of the chemicals they desperately want to sell you. It is up to them to provide you with the active ingredients that provide their market advantage. It is up to them to stay up to date and revise their SDS's when new information comes to light. Why would it be in the interests of the chemical manufacturers to provide updated information when the two most significant authorities on chemical safety can't agree? Australia needs to weigh-in and add their insights and update their exposure standards for the optimal health and welfare of Australians.
Again the poor employer who wears most of the obligation is left with the decision to determine what is the safest way to use this chemical, without really knowing, how bad is it? So of course the best advice we can provide is- manage the risk of exposure to as low as reasonably practicable, because we don't know what level of occupational exposure is actually acceptable.
Benbrook, C.M. How did the US EPA and IARC reach diametrically opposed conclusions on the genotoxicity of glyphosate-based herbicides?. Environ Sci Eur 31, 2 (2019). https://doi.org/10.1186/s12302-018-0184-7