Glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, who worked for the Swiss company Cilag. The work was never published.: 1 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 brandname. 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.
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. In 2010 Powles stated: “glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease.”
As of April 2017, the Canadian government stated that glyphosate was “the most widely used herbicide in Canada”, at which date the product labels were revised to ensure a limit of 20% POEA by weight. [failed verification] Health Canada’s Pest Management Regulatory Agency found no risk to humans or the environment at that 20% limit, and that all products registered in Canada at that time were at or below that limit.
In March 2015, 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.”