History of Glyphosate in Timeline

Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. As an organophosphorus compound, it functions by inhibiting the plant enzyme EPSP synthase. Marketed by Monsanto in 1974 under the name Roundup, glyphosate-based herbicides (GBHs) are designed to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Monsanto's key U.S. patent for Glyphosate expired in 2000.

1950: Glyphosate Synthesized by Henry Martin

In 1950, Glyphosate was first synthesized by Swiss chemist Henry Martin working for Cilag. This work was never published and early studies found Glyphosate to be a weak chemical chelating agent.

1970: Independent Discovery at Monsanto

In 1970, Glyphosate was independently discovered at Monsanto in the United States while preparing derivatives of aminomethylphosphonic acid as potential water-softening agents.

1970: Antimicrobial Activity of Glyphosate

In 1970, the antimicrobial activity of glyphosate was described in the microbiology literature.

1972: Description of Glyphosate's Mechanism of Action

In 1972, the description of glyphosate's mechanism of action was published.

1974: Monsanto Markets Glyphosate as Roundup

In 1974, Monsanto first brought Glyphosate to market under the Roundup brandname.

1974: Monsanto Introduces Roundup

In 1974, Monsanto, an American agricultural company, introduced Glyphosate for agricultural use under the trade name Roundup.

1987: Franz Receives National Medal of Technology

In 1987, John E. Franz received the National Medal of Technology of the United States for his discovery of Glyphosate.

1990: Franz Receives Perkin Medal

In 1990, John E. Franz received the Perkin Medal for Applied Chemistry for his discoveries related to Glyphosate.

1991: Initial Patent Expiration

In 1991, Monsanto's initial patent for Glyphosate expired.

1993: EPA Considered Glyphosate to be Noncarcinogenic

In 1993, the EPA considered glyphosate to be noncarcinogenic and relatively low in dermal and oral acute toxicity.

1994: Glyphosate Use in Colombia's Coca Eradication Programs

Since 1994, Glyphosate has been used in aerial spraying in Colombia in coca eradication programs.

1996: HSNO Act 1996

In 1996, New Zealand implemented the HSNO Act 1996, requiring crops treated with glyphosate to be regulated under this act.

1996: Commercial Availability of Genetically Modified Soybeans

In 1996, genetically modified soybeans with CP4 EPSPS gene, resistant to Glyphosate were made commercially available.

1997: ACVM Act 1997

In 1997, New Zealand implemented the ACVM Act 1997, requiring crops treated with glyphosate to be regulated under this act.

1997: US Government Report on POEA content in Roundup

In 1997, a US government report stated that Roundup is 15% POEA while Roundup Pro is 14.5%.

September 2000: Expiration of Monsanto's Isopropylamine Salt Patent

In September 2000, Monsanto retained exclusive rights in the United States until its patent on the isopropylamine salt expired.

2000: Studies on the effects of Roundup

As of 2000, at least 58 studies existed on the effects of Roundup on a range of organisms. This review concluded that "...for terrestrial uses of Roundup minimal acute and chronic risk was predicted for potentially exposed non-target organisms".

2000: Expiration of Monsanto's U.S. Patent

In 2000, Monsanto's last commercially relevant United States patent for Glyphosate expired.

2003: Study on Glyphosate Formulations and Aquatic Organisms

A 2003 study of various formulations of glyphosate found that risk to aquatic organisms is negligible or small at application rates less than 4 kg/ha and only slightly greater at application rates of 8 kg/ha when used for the control of undesirable plants in wetlands and over-water situations.

2005: Slow Upward Trend of Resistant Weeds

In 2005 a slow upward trend began, resistant weeds appearing rarely around the world.

2007: Glyphosate's Prominent Use in the United States

In 2007, Glyphosate was reported to be the most used herbicide in the United States' agricultural sector.

2007: EPA Selects Glyphosate for Further Screening

In 2007, the EPA selected glyphosate for further screening through its Endocrine Disruptor Screening Program (EDSP). Selection for this program is based on a compound's prevalence of use and does not imply particular suspicion of endocrine activity.

2008: USDA ARS Describes Glyphosate as "Virtually Ideal"

In 2008, scientists at the United States Department of Agriculture Agricultural Research Service (USDA ARS) described glyphosate as a "virtually ideal" herbicide.

2010: Glyphosate Products on the Market

As of 2010, more than 750 glyphosate products were on the market in the United States and worldwide.

2010: Powles' Statement on Glyphosate's Importance

In 2010, Powles stated that "glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease."

2010: Trade dispute filed over glyphosate dumping

In 2010, United States companies reported trade issues related to the dumping of glyphosate into Western markets by Chinese companies, leading to the filing of a formal dispute.

2011: Inflection Point in Resistance

Another inflection point occurred in 2011 and resistance accelerated globally.

2012: Glyphosate Consumption

In 2012, about half of the total global consumption of glyphosate by volume was for agricultural crops, with forestry comprising another important market.

2013: Meta-Analysis of Glyphosate Impacts on Amphibians

A 2013 meta-analysis reviewed the available data related to potential impacts of glyphosate-based herbicides on amphibians. According to the authors, the use of glyphosate-based pesticides cannot be considered the major cause of amphibian decline.

2013: Systematic Review by German Institute for Risk Assessment (BfR)

In 2013, a systematic review by the German Institute for Risk Assessment (BfR) examined more than 1000 epidemiological studies, animal studies, and in vitro studies regarding glyphosate.

January 2014: BfR Provides Review to EFSA

In January 2014, the German Institute for Risk Assessment (BfR) provided its review of glyphosate to EFSA.

December 2014: EFSA Publishes BfR Review

In December 2014, EFSA published the review from the German Institute for Risk Assessment (BfR) regarding glyphosate.

2014: Chinese Manufacturers Lead Glyphosate Production

As of 2014, Chinese manufacturers collectively are the world's largest producers of glyphosate and its precursors and account for about 30% of global exports.

2014: Glyphosate-Resistant Weeds Dominate Herbicide-Resistance Research

By 2014, glyphosate-resistant weeds dominated herbicide-resistance research. At that time, 23 glyphosate-resistant species were found in 18 countries.

March 2015: California Plans to List Glyphosate as a Known Carcinogen

In March 2015, the California Office of Environmental Health Hazard Assessment (OEHHA) announced plans to have glyphosate listed as a known carcinogen based on the IARC assessment.

March 2015: IARC Classifies Glyphosate as "Probably Carcinogenic"

In March 2015, the International Agency for Research on Cancer (IARC) published a summary of their forthcoming monograph on glyphosate and classified glyphosate as "probably carcinogenic in humans" (category 2A).

May 2015: Colombia Announces End to Glyphosate Use

In May 2015, Colombia announced that by October, it would cease using glyphosate in coca eradication programs due to concerns about human toxicity.

June 29, 2015: EPA Releases Weight of Evidence Conclusions

On June 29, 2015, the EPA released the Weight of Evidence Conclusions of the EDSP Tier 1 screening for glyphosate, recommending that glyphosate not be considered for Tier 2 testing, stating there was no convincing evidence of potential interaction with the estrogen, androgen or thyroid pathways.

November 2015: EFSA Publishes Renewal Assessment Report

In November 2015, EFSA published its conclusion in the Renewal Assessment Report (RAR), stating it was "unlikely to pose a carcinogenic hazard to humans".

November 2015: Criticism of EFSA Decision and BfR Report

In November 2015, EFSA's decision and the BfR report were criticized in an open letter published by 96 scientists, saying that the BfR report failed to adhere to accepted scientific principles of open and transparent procedures.

November 2015: European Food Safety Authority's Conclusion

In November 2015, the European Food Safety Authority concluded that glyphosate is unlikely to be genotoxic or pose a carcinogenic threat to humans.

2015: Henry Miller's Opinion Piece in Forbes Magazine

In 2015, Monsanto engaged Henry Miller to write an opinion piece in Forbes Magazine challenging the IARC report. Miller did not reveal the connection to Forbes, and according to The New York Times, when Monsanto asked him if he was interested in writing such an article, he replied "I would be if I could start from a high-quality draft" provided by the company. Once this became public, Forbes removed his blog from their site.

2015: Common Use of Polyethoxylated Tallow Amine (POEA)

In 2015, Polyethoxylated tallow amine (POEA) was commonly used as a surfactant in the original Roundup formulation. The percentage of POEA varies in different formulations.

2015: EPA Initiated Toxicity Review

In 2015, the EPA initiated a review of glyphosate's toxicity.

2015: IARC Classification of Glyphosate

In 2015, the International Agency for Research on Cancer classified glyphosate as Group 2A, "probably carcinogenic to humans".

2016: Meta-Analysis on Glyphosate's Effect on Soil

A 2016 meta-analysis concluded that at typical application rates glyphosate had no effect on soil microbial biomass or respiration.

2016: Increase in Glyphosate Use Worldwide

From the late 1970s to 2016, there was a 100-fold increase in the frequency and volume of application of Glyphosate-based herbicides worldwide.

2016: Analysis by Christopher Portier

In 2016, Christopher Portier, a scientist advising the IARC, concluded that the EFSA's Renewal Assessment Report gave "almost no weight is given to studies from the published literature and there is an over-reliance on non-publicly available industry-provided studies".

2016: Monsanto Starts Case Against OEHHA

In 2016, Monsanto started a case against the California Office of Environmental Health Hazard Assessment (OEHHA) and its acting director, Lauren Zeise.

2016: Lawsuits filed against Quaker Oats and General Mills

In 2016, Quaker Oats faced a lawsuit in New York and California Federal district courts after trace amounts of glyphosate were detected in their oatmeal, challenging their "100% natural" claim. Also in 2016, General Mills removed the "Made with 100% Natural Whole Grain Oats" label from Nature Valley granola bars due to a similar lawsuit.

2016: EU Member States Pesticide Residue Controls

In 2016, pesticide residue controls carried out by EU Member States analysed 6,761 samples of food products for glyphosate residues, with 3.6% containing quantifiable levels and 0.28% exceeding European maximum residue levels (MRLs).

2016: EPA Report on Carcinogenicity of Glyphosate

In 2016, the EPA reported that glyphosate is likely not carcinogenic.

2016: WHO and FAO Report on Glyphosate

In 2016, the WHO and FAO Joint committee on pesticide residues issued a report stating the use of glyphosate formulations does not necessarily constitute a health risk, giving an acceptable daily intake limit of 1 milligram per kilogram of body weight per day for chronic toxicity.

March 15, 2017: ECHA Recommendations from Risk Assessment

On March 15, 2017, the European Chemicals Agency (ECHA) announced recommendations proceeding from a risk assessment of glyphosate performed by ECHA's Committee for Risk Assessment (RAC). Their recommendations maintained the current classification of glyphosate as a substance causing serious eye damage and as a substance toxic to aquatic life.

March 2017: Monsanto Loses Suit Against OEHHA

In March 2017, Monsanto lost the suit they started against the California Office of Environmental Health Hazard Assessment (OEHHA) and its acting director, Lauren Zeise.

April 2017: Glyphosate Usage in Canada

As of April 2017, the Canadian government's Pest Management Regulatory Agency stated that glyphosate was "the most widely used herbicide in Canada" and that approved glyphosate formulations in the country contained less than 20% polyethoxylated tallow amines (POEA surfactants) by weight. The agency found no risk to humans or the environment at that 20% limit.

September 2017: European Food Safety Authority Review

In September 2017, the European Food Safety Authority published a review of the evidence that showed conclusions similar to those of the EPA report regarding glyphosate.

October 2017: Article Reveals Portier's Consulting Contracts

In October 2017, an article in The Times revealed that Portier had received consulting contracts with two law firm associations representing alleged glyphosate cancer victims and that the IARC final report was found to have changed compared to an interim report.

November 2017: EU Decision on Glyphosate Use

In November 2017, the EU made its decision on the use of glyphosate, largely informed by EFSA's Renewal Assessment Report.

2017: EFSA and BfR Review of IARC's Conclusions

A 2017 review done by personnel from EFSA and BfR argued that the differences between the IARC's and EFSA's conclusions regarding glyphosate and cancer were due to differences in their evaluation of the available evidence.

2017: Glyphosate Listed as Known Carcinogen in California

In 2017, Glyphosate was listed as "known to the State of California to cause cancer", requiring warning labels under Proposition 65.

2017: ECHA Risk Assessment on Glyphosate

In 2017, a risk assessment by the European Chemicals Agency (ECHA) indicated limited information on skin irritation in humans related to glyphosate and concluded that available data was insufficient for skin corrosion or irritation classification.

2017: Evidence of Friendly Relationship Between Monsanto and EPA

In 2017, evidence collected in a lawsuit brought against Monsanto by cancer patients revealed company emails that appeared to show a friendly relationship with a senior EPA official.

2017: Monsanto Papers Made Public

In 2017, internal documents from Monsanto were made public by lawyers pursuing litigation against the company, who used the term "Monsanto papers" to describe the documents. The documents indicated Monsanto had planned a public relations effort to discredit the IARC report.

2017: ECHA Classification of Glyphosate

In 2017, the European Chemicals Agency (ECHA) classified glyphosate as causing serious eye damage and as toxic to aquatic life but did not find evidence implicating it as a carcinogen, a mutagen, toxic to reproduction, nor toxic to specific organs.

February 2018: Injunction Prohibiting Carcinogenicity Labeling in California

In February 2018, as part of an ongoing case, an injunction was issued prohibiting California from enforcing carcinogenicity labeling requirements for glyphosate until the case was resolved.

2018: European Press Prize for Articles on Monsanto Papers

In 2018, two journalists from Le Monde won the European Press Prize for a series of articles on the documents, also titled Monsanto Papers. Their reporting described, among other things, Monsanto's lawyers' letters demanding that IARC scientists turn over documents relating to Monograph 112, which contained the IARC finding that glyphosate was a "probable carcinogen"; several of the scientists condemned these letters as intimidating.

2018: Court cases link glyphosate to cancer

Since 2018, numerous court cases in the United States have seen plaintiffs claiming that their cancer resulted from exposure to glyphosate in herbicides produced by Monsanto/Bayer. Bayer has paid over $9.6 billion in settlements but has also won cases arguing their herbicides were not responsible.

August 2019: EPA Restriction on Carcinogen Labels

In August 2019, the EPA also said it no longer allowed labels claiming glyphosate is a carcinogen, as those claims would "not meet the labeling requirements of the Federal Insecticide, Fungicide, and Rodenticide Act" and misinform the public.

2020: Evidence for Long-Term Exposure to Glyphosate

As of 2020, the evidence for long-term exposure to glyphosate increasing the risk of human cancer remains inconclusive. There is weak evidence human cancer risk might increase as a result of occupational exposure to large amounts of glyphosate.

2021: Glyphosate found in New Zealand honey exports.

In 2021, New Zealand honey exports were found to contain traces of glyphosate, raising concerns among Japanese importers.

2022: ECHA Reiterated Findings on Glyphosate

In 2022, the European Chemicals Agency (ECHA) reiterated their findings from 2017 in a later review and stated on cancer risk that, "Based on a wide-ranging review of scientific evidence, the committee again concludes that classifying glyphosate as a carcinogen is not justified."

July 2023: EFSA Re-evaluation of Glyphosate

In July 2023, EFSA re-evaluated the putative impact of glyphosate on the health of humans, animals and the environment after three years of assessment. As a result, no critical areas of concern were identified that would otherwise prevent glyphosate's registration renewal in the EU.

2023: Prevalence of Herbicide-Tolerant Crops in the U.S.

In 2023, 91% of corn, 95% of soybeans, and 94% of cotton produced in the United States were from strains genetically modified to be tolerant to multiple herbicides, including dicamba, glufosinate, and glyphosate.

2024: Meta-Analysis of Glyphosate Effects on Animals

A 2024 meta-analysis of 121 studies determined that glyphosate and glyphosate-based herbicides effects on animals were generally sublethal, with relatively larger effects in aquatic and marine species, though it also found widespread publication bias that may inflate the reported magnitude of these effects.

Mentioned in this timeline

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