In an open letter to the European Commission, Portier said the EU agencies had failed to include in their assessments data from eight animal studies that suggested glyphosate was carcinogenic.
He said: "This suggests that the evaluations applied to the glyphosate data are scientifically flawed."
Anti-glyphosate activist Portier who served as an invited specialist for IARC 112 Monograph now represents the Health and Environment Alliance which recently called for a petition to ban glyphosate in the European Union.
The European Food Safety Authority (EFSA) and the European Chemicals Agency (ECHA), have both found that the herbicide is not carcinogenic. A spokesperson for the Commission said both organisations would be asked to provide responses to Portier’s letter.
Portier has published a study contrary to EFSA's findings called 'Differences in the carcinogenic evaluation of glyphosate between the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA).'
EU Commissioner for Health and Food Safety Vytenis Andriukaitis said politics should not outweigh science in the debate over glyphosate: "I must be humble, I am not a scientific expert, but it seems to me that political opinions cannot outweigh broadly agreed scientific opinions. As a doctor, I rely on science. Therefore, I will continue to base my decisions on science and on the rule of law."
Meanwhile, last week, on 25 May, the US has made moves for some deregulation in the field of pesticides. The House of Representatives approved bipartisan legislation to eliminate an ''unnecessary, duplicative, and costly regulatory process" under the Environmental Protection Agency (EPA) for the approved use of pesticides, which may reflect what could happen in the UK, post-Brexit.
According to the House Committee on Agriculture, HR 953, the Reducing Regulatory Burdens Act of 2017, ensures states, local governments, mosquito control districts, and other lawful users of pesticides are able to protect public health and not be overburdened with regulatory processes that provide no additional protections to the environment.
Some 25 Democrats voted in favour of the bill. Most Democrats, though, opposed the bill on public health grounds, saying the legislation would fast track permitting decisions for potentially-dangerous pesticides, putting water quality at risk.
"We’ve seen the consequences of this duplicative and unnecessary permitting requirement since it went into effect in 2011," said US Rep. Bob Gibbs, the sponsor of H.R. 953.
"Cities and local governments that conduct routine preventive mosquito abatement should not have to do it with one hand tied behind their backs.
"This bill ensures the permitting process adheres to EPA’s current authority under the Federal Insecticide, Fungicide, and Rodenticide Act to approve and regulate these lifesaving pesticides.
"This is a commonsense measure that provides peace of mind to those living in communities prone to mosquitos by eliminating the need for a redundant permit that diverts resources from the mission of protecting public health."
* Roundup's makers say they have no plans for a UK glyphosate-free Roundup weedkiller product after one was introduced in Austria, Germany and France.