More than 9.4 million tons of Roundup and other glyphosate-based herbicides have been used to kill weeds around the world since 1974. About two-thirds of that has been sprayed just since 2004. Bayer and Monsanto, Roundup’s manufacturers, say the product line is safe. But a growing number of people who’ve worked with it blame glyphosate for causing cancer.
Spraying plants with pesticides
International regulators and researchers disagree on whether Roundup and other glyphosate-based herbicides increase the risk of cancer.
Studies of cancer rates in people exposed to glyphosate have returned conflicting results, according to the National Pesticide Information Center. But the center says some studies have associated glyphosate-based herbicides with non-Hodgkin lymphoma.
Research into an association between glyphosate and cancer in humans is very limited. Studies have shown large doses of the chemical may cause cancer in animals. But results from animal tests don’t always translate to the same results in humans.
Drug and chemical giant Bayer AG acquired Roundup’s original manufacturer, Monsanto, in 2018. Bayer’s glyphosate website touts “more than 800 rigorous studies” on glyphosate conducted for the United States, European and other regulators. It says these studies confirm glyphosate is not carcinogenic. But company emails from 2002 suggest no studies at that time had determined whether Roundup posed a cancer risk.