It's the most commonly used - and perhaps also most controversial - herbicide in the world: glyphosate. Opinion between the European Food Standards Agency (EFSA) and the World Health Organization (WHO) is divided over whether it likely causes cancer.
And on Tuesday (01.12.2015), the European Parliament debated the topic. In the leadup to each side presenting their positions, 96 scientists from 25 countries published an open letter to EU Health Commissioner Vytenis Andriukaitis, criticizing the EFSA's recent decision that the chemical is "probably not carcinogenic."
The EFSA's finding counters an assessment earlier this year by the World Health Organization's International Agency for Research on Cancer (IARC), that glyphosate is a "probable human carcinogen."
In their letter, the scientists called on the European Commission "to disregard the flawed EFSA finding on glyphosate," and called for a "transparent, open and credible review of the scientific literature."
The EFSA's decision was based on assessment by the German Federal Institute for Risk Assessment (BfR), which the signatories to the letter said was "not credible because it is not supported by the evidence, and it was not reached in an open and transparent manner."
The scientists called the IARC's assessment more credible. The lead signatory of the letter, Christopher Portier, told DW that the scientists felt compelled to submit their letter because, "as a group, we thought that decision was not supported scientifically."
"It was based on a rejection of what other experts judge to be a positive association between glyphosate and cancer in humans," Portier said.
Portier is senior contributing scientist at the Envrionmental Defense, and former associate director of the United States National Toxicology Program.
The group from the letter also includes scientists specializing in cancer, epidemiology and public health at major universities and cancer research institutes around the world - although they stressed that they were not speaking on behalf of these organizations.
Doctors report rise in cancer
Glyphosate was developed by transnational chemical company Monsanto, and is the key ingredient in its herbicide Roundup. Glyphosate is also sold by other major corporations including Syngenta and Bayer.
Doctors, environmentalists and some farmers have long called for a ban on the pesticide.
"We can clearly see that people are getting sick from glyphosate," Argentine pediatrician Medardo Avila Vazquez told DW in a recent interview. "There are frequent cases of lung, breast and bowel cancer" through glyphosate, he added.
Vazquez, a pharmacologist who has carried out epidemiological studies in Argentina, added that cancer was not the only concern.
"In villages surrounded by soy fields, where lots of glyphosate is sprayed, we note that the number of miscarriages has risen sharply," he said. "There is also a strong rise in the number in birth defects in these areas."
Quality over quantity
Speaking to the European Parliament on Tuesday, the EFSA said that it had reached its assessment based on a larger number of studies that the IARC did not include. EFSA director Bernhard Url told lawmakers it was "the most state-of-the-art and comprehensive assessment to date."
The IARC countered that it went "for quality over quantity," and looked at a narrower range of peer-reviewed studies by excluding those not in the public domain, and which are therefore unavailable to review and criticism by other scientists.
The IARC also stressed that scientists selected for its assessment process were neutral, and lacked any conflict of interest.
Before the end of June 2016, the European Commission is to make a decision on whether or not to relicense glyphosate in the EU, for up to 15 years.
Parliamentarians and European Commissioners stressed a responsibility to public health in proper assessment of the chemical's impacts, and the intention to issue an appropriate ruling in response.
Also present in public discussion are warnings of a potential fall in crop yields if approval for the pesticide, which European agriculture is heavily dependent upon, were to be withdrawn.
Portier says he hopes the UN will reconsider how it assesses chemicals.
"We hope this letter improves the ways pesticides are reviewed in the future," he told DW.