A long-term study into the health effects of the controversial herbicide glyphosate, found in Monsanto’s popular Roundup product, has found no link between exposure to the chemical and cancer.

Carried out as part of the Agricultural Health Study (AHS) tracking the health of farmers and their families in the US states of Iowa and North Carolina, the study found no association between glyphosate and “any solid tumours of lymphoid malignancies overall, including non-Hogkin Lymphoma”, wrote Reuters on 9 November.

There was some evidence that glyphosate could increase the risk of acute myeloid leukemia among the highest exposed group, but the study said the association was “not statistically significant”.

The findings of the study could impact ongoing legal proceedings in the USA – where 180 plaintiffs have sued Monsanto claiming glyphosate caused them to develop cancer – and the EU’s decision on whether to renew glyphosate’s usage license.

The EU had until the end of the year to make its decision but had again failed to agree on a proposed five-year extension in early November, Reuters said.

The decision had been delayed for over a year after the World Health Organization found glyphosate to be “probably carcinogenic” in humans.

Reuters reported in June that during the International Agency for Research on Cancer’s (IARC) review of glyphosate, an influential scientist was aware of the findings of the AHS study but failed to disclose them to the IARC panel due to the study being unpublished at the time.

Monsanto vice president of strategy Scott Partridge, told Reuters the AHS study was “the largest on agricultural workers in history over the longest period of time” and “the gold standard” that definitively demonstrated the safety of glyphosate.