Glyphosate News and Facts
Glyphosate [N-(phosphonomethyl)glycine] is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops.
Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup, but its last commercially relevant United States patent expired in 2000.
Farmers quickly adopted glyphosate for agricultural weed control, especially after Monsanto introduced glyphosate-resistant Roundup Ready crops, enabling farmers to kill weeds without killing their crops. In 2007, glyphosate was the most used herbicide in the United States’ agricultural sector and the second-most used (after 2,4-D) in home and garden, government and industry, and commercial applications. From the late 1970s to 2016, there was a 100-fold increase in the frequency and volume of application of glyphosate-based herbicides (GBHs) worldwide, with further increases expected in the future, partly in response to the global emergence and spread of glyphosate-resistant weeds requiring greater application to maintain effectiveness. The development of glyphosate resistance in weed species is emerging as a costly problem.
Glyphosate is absorbed through foliage, and minimally through roots, and transported to growing points. It inhibits a plant enzyme involved in the synthesis of three aromatic amino acids: tyrosine, tryptophan, and phenylalanine. It is therefore effective only on actively growing plants and is not effective as a pre-emergence herbicide. An increasing number of crops have been genetically engineered to be tolerant of glyphosate (e.g. Roundup Ready soybean, the first Roundup Ready crop, also created by Monsanto), which allows farmers to use glyphosate as a post-emergence herbicide against weeds.
While glyphosate and formulations such as Roundup have been approved by regulatory bodies worldwide, concerns about their effects on humans and the environment persist, and have grown as the global usage of glyphosate increases.
With that expanded usage, of course, go expanded sales. Glyphosate has become a billion dollar product for Monsanto and the decision of a single health agency as to its safety can mean the gain or loss of $100 million in annual sales in a single country.
In March 2015, for example, the World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic in humans” (category 2A) based on epidemiological studies, animal studies, and in vitro studies. In contrast, the European Food Safety Authority concluded in November 2015 that “the substance is unlikely to be genotoxic (i.e. damaging to DNA) or to pose a carcinogenic threat to humans”, later clarifying that while carcinogenic glyphosate-containing formulations may exist, studies “that look solely at the active substance glyphosate do not show this effect.”
How can such differences exist in hard scientific opinion? It turns out that the European Agency based its findings on data a German institution put together which was drawn from a report created by the Glyphosate Task Force, a consortium of chemical companies, including Monsanto, with the stated goal of winning renewal of glyphosate’s registration in Europe. Greenpeace called the EFSA’s report a “whitewash” that relied heavily on unpublished studies commissioned by glyphosate producers while dismissing published peer-reviewed evidence that glyphosate causes cancer. This sort of active effort by Monsanto and the chemical industry to contest criticism of their products is rampant in regulatory decision-making.
Glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, who worked for the Swiss company Cilag. The work was never published. Stauffer Chemical patented the agent as a chemical chelator in 1964 as it binds and removes minerals such as calcium, magnesium, manganese, copper, and zinc.
Somewhat later, glyphosate was independently discovered in the United States at Monsanto in 1970. Monsanto chemists had synthesized about 100 derivatives of aminomethylphosphonic acid as potential water-softening agents. Two were found to have weak herbicidal activity, and John E. Franz, a chemist at Monsanto, was asked to try to make analogs with stronger herbicidal activity. Glyphosate was the third analog he made. Franz received the National Medal of Technology of the United States in 1987 and the Perkin Medal for Applied Chemistry in 1990 for his discoveries.
Monsanto developed and patented the use of glyphosate to kill weeds in the early 1970s and first brought it to market in 1974, under the Roundup brand name. While its initial patent expired in 1991, Monsanto retained exclusive rights in the United States until its patent on the isopropylamine salt expired in September 2000.
Mode of action
Glyphosate is such a valuable product largely because of its widespread effectiveness. In 2008, United States Department of Agriculture (USDA) Agricultural Research Service (ARS) scientist Stephen O. Duke and Stephen B. Powles—an Australian weed expert—described glyphosate as a “virtually ideal” herbicide.
Glyphosate interferes with the shikimate pathway, which produces the aromatic amino acids phenylalanine, tyrossine, and tryptophan in plants and microorganisms – but does not exist in the genome of mammals, including humans. It blocks this pathway by inhibiting an enzyme which catalyzes this reaction.
Glyphosate is absorbed through foliage and minimally through roots, meaning that it is only effective on actively growing plants and cannot prevent seeds from germinating. After application, glyphosate is readily transported around the plant to growing roots and leaves and this systemic activity is important for its effectiveness. Inhibiting the enzyme causes shikimate to accumulate in plant tissues and diverts energy and resources away from other processes, eventually killing the plant. While growth stops within hours of application, it takes several days for the leaves to begin turning yellow.
Glyphosate is effective in killing a wide variety of plants, including grasses and broadleaf and woody plants. By volume, it is one of the most widely used herbicides. In 2007, glyphosate was the most used herbicide in the United States agricultural sector, with 180 to 185 million pounds (82,000 to 84,000 tons) applied, the second-most used in home and garden with 5 to 8 million pounds (2,300 to 3,600 tons) and government applied 13 to 15 million pounds (5,900 to 6,800 tons) in industry and commerce. It is commonly used for agriculture, horticulture, viticulture, and silviculture purposes, as well as garden maintenance (including home use). It has a relatively small effect on some clover species and morning glory.
Glyphosate and related herbicides are often used in invasive species eradication and habitat restoration, especially to enhance native plant establishment in prairie ecosystems. The controlled application is usually combined with a selective herbicide and traditional methods of weed eradication such as mulching to achieve an optimal effect.
In many cities, glyphosate is sprayed along the sidewalks and streets, as well as crevices in between pavement where weeds often grow. However, up to 24% of glyphosate applied to hard surfaces can be run off by water. Glyphosate contamination of surface water is attributed to urban and agricultural use. Glyphosate is used to clear railroad tracks and get rid of unwanted aquatic vegetation. Since 1994, glyphosate has been used in aerial spraying in Colombia in coca eradication programs; Colombia announced in May 2015 that by October, it would cease using glyphosate in these programs due to concerns about human toxicity of the chemical.
Glyphosate is also used for crop desiccation (siccation) to increase harvest yield and uniformity. Glyphosate itself is not a chemical desiccant; rather glyphosate application just before harvest kills the crop plants so that the food crop dries from environmental conditions (“dry-down”) more quickly and evenly. Because glyphosate is systemic, excess residue levels can persist in plants due to incorrect application and this may render the crop unfit for sale. When applied appropriately, it can promote useful effects. In sugarcane, for example, glyphosate application increases sucrose concentration before harvest. In grain crops (wheat, barley, oats), uniformly dried crops do not have to be windrowed (swathed and dried) prior to harvest, but can easily be straight-cut and harvested. This saves the farmer time and money, which is important in northern regions where the growing season is short, and it enhances grain storage when the grain has a lower and more uniform moisture content.
Genetically modified crops
Some micro-organisms are resistant to glyphosate inhibition. A version of an enzyme that was both resistant to glyphosate and that was still efficient enough to drive adequate plant growth was identified by Monsanto scientists after much trial and error in an Agrobacterium strain called CP4, which was found surviving in a waste-fed column at a glyphosate production facility. This CP4 EPSPS gene was cloned and transfected into soybeans. In 1996, genetically modified soybeans were made commercially available. Current glyphosate-resistant crops include soy, maize (corn), canola, alfalfa, sugar beets, and cotton, with wheat still under development.
In 2015, 89% of corn, 94% of soybeans, and 89% of cotton produced in the United States were from strains that were genetically modified to be herbicide-tolerant.
Glyphosate adsorbs strongly to soil, and residues are expected to generally be immobile in soil. (Adsorbtion is the taking up of organic compounds by soils or sediments) Glyphosate is readily degraded by soil microbes to aminomethylphosphonic acid (AMPA, which like glyphosate strongly adsorbs to soil solids and is thus unlikely to leach to groundwater). Though both glyphosate and AMPA are commonly detected in water bodies, a portion of the AMPA detected may actually be the result of degradation of detergents rather than from glyphosate. Glyphosate does have the potential to contaminate surface waters due to its aquatic use patterns and through erosion, as it adsorbs to soil particles suspended in runoff.
Detection in surface waters (particularly downstream from agricultural uses) has been reported as both broad and frequent by USGS researchers, although other similar research found equal frequencies of detection in urban-dominated small streams. Rain events can trigger dissolved glyphosate loss in transport-prone soils. The mechanism of glyphosate sorption to soil is similar to that of phosphate fertilizers, the presence of which can reduce glyphosate sorption. Phosphate fertilizers are subject to release from sediments into water bodies under anaerobic conditions, and similar release can also occur with glyphosate, though significant impact of glyphosate release from sediments has not been established. Limited leaching can occur after high rainfall after application. If glyphosate reaches surface water, it is not broken down readily by water or sunlight.
The half-life of glyphosate in soil ranges between 2 and 197 days; a typical field half-life of 47 days has been suggested. Soil and climate conditions affect glyphosate’s persistence in soil. The median half-life of glyphosate in water varies from a few to 91 days. At a site in Texas, half-life was as little as three days. A site in Iowa had a half-life of 141.9 days. The glyphosate metabolite AMPA has been found in Swedish forest soils up to two years after a glyphosate application. In this case, the persistence of AMPA was attributed to the soil being frozen for most of the year. Glyphosate adsorption to soil, and later release from soil, varies depending on the kind of soil. Glyphosate is generally less persistent in water than in soil, with 12- to 60-day persistence observed in Canadian ponds, although persistence of over a year has been recorded in the sediments of American ponds. The half-life of glyphosate in water is between 12 days and 10 weeks.
Residues in food products
According to the National Pesticide Information Center fact sheet, glyphosate is not included in compounds tested for by the Food and Drug Administration’s Pesticide Residue Monitoring Program, nor in the United States Department of Agriculture’s Pesticide Data Program. However, a field test showed that lettuce, carrots, and barley contained glyphosate residues up to one year after the soil was treated with 3.71 lb of glyphosate per acre (4.15 kg per hectare). The U.S. has determined the acceptable daily intake of glyphosate at 1.75 milligrams per kilogram of bodyweight per day (mg/kg/bw/day) while the European Union has set it at 0.5.
Pesticide residue controls carried out by EU Member States in 2016 analysed 6,761 samples of food products for glyphosate residues. 3.6% of the samples contained quantifiable glyphosate residue levels with 19 samples (0.28%) exceeding the European maximum residue levels (MRLs), which included six samples of honey and other apicultural products (MRL = 0.05 mg/kg) and eleven samples of buckwheat and other pseudocereals (MRL = 0.1 mg/kg). Glyphosate residues below the European MRLs were most frequently found in dry lentils, linseeds, soya beans, dry peas, tea, buckwheat, barley, wheat and rye.
Glyphosate is the active ingredient in herbicide formulations containing it. However, in addition to glyphosate salts, commercial formulations of glyphosate contain additives (known as adjuvants) such as surfactants, which vary in nature and concentration. Surfactants such as polyethoxylated tallow amine (POEA) are added to glyphosate to enable it to wet the leaves and penetrate the cuticle of the plants.
The acute oral toxicity for mammals is low, but death has been reported after deliberate overdose of concentrated formulations. The surfactants in glyphosate formulations can increase the relative acute toxicity of the formulation. In a 2017 risk assessment, the European Chemicals Agency (ECHA) wrote: “There is very limited information on skin irritation in humans. Where skin irritation has been reported, it is unclear whether it is related to glyphosate or co-formulants in glyphosate-containing herbicide formulations.” The ECHA concluded that available human data was insufficient to support classification for skin corrosion or irritation. Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate.
The question whether labeled uses of glyphosate have demonstrated evidence of human carcinogenicity is hotly contested. A number of European agencies have concluded that there is no evidence that glyphosate poses a carcinogenic or genotoxic risk to humans. The EPA has classified glyphosate as “not likely to be carcinogenic to humans.” One international scientific organization, however, the International Agency for Research on Cancer, classified glyphosate in Group 2A, “probably carcinogenic to humans” in 2015.
There is evidence human cancer risk might increase as a result of occupational exposure to large amounts of glyphosate, such as agricultural work. According to one systematic review and meta-analysis published in 2016, when weak statistical associations with cancer have been found, such observations have been attributed to bias and confounding in correlational studies due to workers often being exposed to other known carcinogens. The review reported that studies that show an effect between glyphosate use and non-Hodgkin lymphoma have been criticized for not assessing these factors, underlying quality of studies being reviewed, or whether the relationship is causal rather than only correlational. Writing for the Natural Resources Defense Council environmental advocacy group, h owever, Jennifer Sass criticized the influence exerted by Monsanto on research about glyphosate safety, and noted that the review was funded by Monsanto.
A meta-analysis published in 2019 looked at whether there was an association between an increased risk of non-Hodgkin lymphoma in humans and high cumulative exposures to glyphosate-based herbicides. The analysis used the most recent update of the Agricultural Health Study cohort published in 2018 and five case-control studies published in 2019. The research found a “compelling link” between exposures to glyphosate-based herbicides and increased risk for non-Hodgkin lymphoma.
Amongst mammals, glyphosate is considered to have “low to very low toxicity”. The LD50 of glyphosate is 5,000 mg/kg for rats, 10,000 mg/kg in mice and 3,530 mg/kg in goats. The acute dermal LD50 in rabbits is greater than 2,000 mg/kg. Indications of glyphosate toxicity in animals typically appear within 30 to 120 minutes following ingestion of a large enough dose, and include initial excitability and tachycardia (a rapid heart rate), ataxia (impaired coordination), depression, and bradycardia (abnormally slow heart action), although severe toxicity can develop into collapse and convulsions.
A review of unpublished short-term rabbit-feeding studies reported severe toxicity effects at 150 mg/kg/day and “no observed adverse effect level” doses ranging from 50 to 200 mg/kg/day. Glyphosate can have carcinogenic effects in nonhuman mammals. In reproductive toxicity studies performed in rats and rabbits, no adverse maternal or offspring effects were seen at doses below 175–293 mg/kg of body weight per day.
Glyphosate-based herbicides may cause life-threatening arrhythmias in mammals. Evidence also shows that such herbicides cause direct electrophysiological changes in the cardiovascular systems of rats and rabbits.
In many freshwater invertebrates, glyphosate has a 48-hour LC50 ranging from 55 to 780 ppm. The 96-hour LC50 is 281 ppm for grass shrimp (Palaemonetas vulgaris) and 934 ppm for fiddler crabs (Uca pagilator). These values make glyphosate “slightly toxic to practically non-toxic”.
The antimicrobial activity of glyphosate has been described in the microbiology literature since its discovery in 1970 and the description of glyphosate’s mechanism of action in 1972. Efficacy was described for numerous bacteria and fungi. Glyphosate can control the growth of apicomplexan parasites, such as Toxoplasma gondii, Plasmodium falciparum (malaria), and Cryptosporidium parvum, and has been considered an antimicrobial agent in mammals. Inhibition can occur with some Rhizobium species important for soybean nitrogen fixation, especially under moisture stress.
When glyphosate comes into contact with the soil, it can be bound to soil particles, thereby slowing its degradation. A 2016 meta-analysis concluded that at typical application rates glyphosate had no effect on soil microbial biomass or respiration. A 2016 review noted that contrasting effects of glyphosate on earthworms have been found in different experiments with some species unaffected, but others losing weight or avoiding treated soil. Further research is required to determine the impact of glyphosate on earthworms in complex ecosystems.
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. On June 29, 2015, the EPA released Weight of Evidence Conclusion of the EDSP Tier 1 screening for glyphosate, recommending that glyphosate not be considered for Tier 2 testing. The Weight of Evidence conclusion stated “…there was no convincing evidence of potential interaction with the estrogen, androgen or thyroid pathways.” A review of the evidence by the European Food Safety Authority published in September 2017 showed conclusions similar to those of the EPA report.
Effect on plant health
Some studies have found causal relationships between glyphosate and increased or decreased disease resistance. Exposure to glyphosate has been shown to change the species composition of endophytic bacteria in plant hosts, which is highly variable.
Glyphosate-based formulations may contain a number of adjuvants, the identities of which may be proprietary. Surfactants are used in herbicide formulations as wetting agents, to maximize coverage and aid penetration of the herbicide(s) through plant leaves. As agricultural spray adjuvants, surfactants may be pre-mixed into commercial formulations or they may be purchased separately and mixed on-site.
Polyethoxylated tallow amine (POEA) is a surfactant used in the original Roundup formulation and was commonly used in 2015. Different versions of Roundup have included different percentages of POEA. A 1997 US government report said that Roundup is 15% POEA while Roundup Pro is 14.5%. Since POEA is more toxic to fish and amphibians than glyphosate alone, POEA is not allowed in aquatic formulations. A 2000 review of the ecotoxicological data on Roundup shows at least 58 studies exist 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”.
Acute toxicity and chronic toxicity are dose-related. Skin exposure to ready-to-use concentrated glyphosate formulations can cause irritation, and photocontact dermatitis has been occasionally reported. These effects are probably due to the preservative benzisothiazolin-3-one. Severe skin burns are very rare. Inhalation is a minor route of exposure, but spray mist may cause oral or nasal discomfort, an unpleasant taste in the mouth, or tingling and irritation in the throat. Eye exposure may lead to mild conjunctivitis. Superficial corneal injury is possible if irrigation is delayed or inadequate. Death has been reported after deliberate overdose.
Ingestion of Roundup ranging from 85 to 200 ml (of 41% solution) has resulted in death within hours of ingestion, although it has also been ingested in quantities as large as 500 ml with only mild or moderate symptoms. Adult consumption of more than 85 ml of concentrated product can lead to corrosive esophageal burns and kidney or liver damage. More severe cases cause “respiratory distress, impaired consciousness, pulmonary edema, infiltration on chest X-ray, shock, arrhythmias, renal failure requiring haemodialysis, metabolic acidosis, and hyperkalaemia” and death is often preceded by bradycardia and ventricular arrhythmias. While the surfactants in formulations generally do not increase the toxicity of glyphosate itself, it is likely that they contribute to its acute toxicity.
A 2000 review concluded that “under present and expected conditions of new use, there is no potential for Roundup herbicide to pose a health risk to humans”. A 2012 meta-analysis of epidemiological studies (seven cohort studies and fourteen case-control studies) of exposure to glyphosate formulations found no correlation with any kind of cancer. The 2013 systematic review by the German Institute for Risk Assessment of epidemiological studies of workers who use pesticides, exposed to glyphosate formulations found no significant risk, stating that “the available data are contradictory and far from being convincing”. However, a 2014 meta-analysis of the same studies found a correlation between occupational exposure to glyphosate formulations and increased risk of B cell lymphoma, the most common kind of non-Hodgkin lymphoma. Workers exposed to glyphosate were about twice as likely to get B cell lymphoma. A 2016 systematic review and meta-analysis found no causal relationship between glyphosate exposure and risk of any type of lymphohematopoietic cancer including non-Hodgkin lymphoma and multiple myeloma. The same review noted that the positive associations found may be due to bias and confounding. The Natural Resources Defense Council has criticized that review, noting that it was funded by Monsanto.
A 2015 systematic review of observational studies found that except for an excess of Attention Deficit Hyperactivity Disorder among children born to glyphosate appliers, no evidence that glyphosate exposure among pregnant mothers caused adverse developmental outcomes in their children. Noting the limited size and scope of the review articles available, the authors noted that “these negative findings cannot be taken as definitive evidence that glyphosate, at current levels of occupational and environmental exposures, brings no risk for human development and reproduction.”
Glyphosate products for aquatic use generally do not use surfactants, and aquatic formulations do not use POEA due to aquatic organism toxicity. Due to the presence of POEA, such glyphosate formulations only allowed for terrestrial use are more toxic for amphibians and fish than glyphosate alone. The half-life of POEA (21–42 days) is longer than that for glyphosate (7–14 days) in aquatic environments. Aquatic organism exposure risk to terrestrial formulations with POEA is limited to drift or temporary water pockets where concentrations would be much lower than label rates.
Some researchers have suggested the toxicity effects of pesticides on amphibians may be different from those of other aquatic fauna because of their lifestyle; amphibians may be more susceptible to the toxic effects of pesticides because they often prefer to breed in shallow, lentic, or ephemeral pools. These habitats do not necessarily constitute formal water-bodies and can contain higher concentrations of pesticide compared to larger water-bodies. Studies in a variety of amphibians have shown the toxicity of GBFs (glypohosate-based formulations) containing POEA to amphibian larvae. These effects include interference with gill morphology and mortality from either the loss of osmotic stability or asphyxiation. At sub-lethal concentrations, exposure to POEA or glyphosate/POEA formulations have been associated with delayed development, accelerated development, reduced size at metamorphosis, developmental malformations of the tail, mouth, eye and head, histological indications of intersex and symptoms of oxidative stress. Glyphosate-based formulations can cause oxidative stress in bullfrog tadpoles.
A 2003 study of various formulations of glyphosate found, “[the] risk assessments based on estimated and measured concentrations of glyphosate that would result from its use for the control of undesirable plants in wetlands and over-water situations showed that the 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.”
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, the bulk of which occurred prior to the widespread use of glyphosate or in pristine tropical areas with minimal glyphosate exposure. The authors recommended further study of species- and development-stage chronic toxicity, of environmental glyphosate levels, and ongoing analysis of data relevant to determining what if any role glyphosate might be playing in worldwide amphibian decline, and suggest including amphibians in standardized test batteries.
Several studies have not found mutagenic effects, so glyphosate has not been listed in the United States Environmental Protection Agency or the International Agency for Research on Cancer databases. Various other studies suggest glyphosate may be mutagenic. The IARC monograph noted that glyphosate-based formulations can cause DNA strand breaks in various taxa of animals in vitro.
Lawsuits claiming liability for cancer
In June 2018, Dewayne Johnson, a 46-year-old former California school groundskeeper who is dying of non-Hodgkin lymphoma, took Monsanto (which had been acquired by Bayer earlier that month) to trial in San Francisco County superior court, alleging that it has spent decades hiding the cancer-causing dangers of its Roundup herbicides. The judge ordered that jurors be allowed to consider both scientific evidence related to the cause of Johnson’s cancer and allegations that Monsanto suppressed evidence of the risks, with possible punitive damages. In August 2018, the jury awarded Johnson US $289 million in damages. Monsanto said they would appeal, saying they were confident that glyphosate does not cause cancer when used appropriately. In November 2018, the award was reduced to $78 million on appeal.
In August 2018, the potential for additional cases was estimated at up to 4,000. Bayer announced in April 2019 that over 13,000 lawsuits related to Roundup had been launched in the US.
In March 2019, a man was awarded $80 million in a lawsuit claiming Roundup was a substantial factor in his cancer, resulting in Costco stores discontinuing sales. In July 2019, U.S. District Judge Vince Chhabria reduced the settlement to $26 million.Chhabria stated that a punitive award was appropriate because the evidence “easily supported a conclusion that Monsanto was more concerned with tamping down safety inquiries and manipulating public opinion than it was with ensuring its product is safe.” Chhabria stated that there is evidence on both sides concerning whether glyphosate causes cancer and that the behavior of Monsanto showed “a lack of concern about the risk that its product might be carcinogenic.”
On May 13, 2019 a jury in California ordered Bayer to pay a couple $2 billion in damages after finding that the company had failed to adequately inform consumers of the possible carcinogenicity of Roundup. On July 26, 2019, an Alameda County judge cut the settlement to $86.7 million, stating that the judgment by the jury exceeded legal precedent.
Using litigation discovery emails it was later revealed that in 2015 when Monsanto was discussing papers they wanted to see published to counter the expected IARC glyphosate results they wrote in an email, “An option would be to add Greim and Kier or Kirkland to have their names on the publication, but we would be keeping the cost down by us doing the writing and they would just edit & sign their names so to speak. Recall that is how we handled Williams Kroes & Munro, 2000.”