What’s Bayer’s Roundup and Why Is It Controversial?

Few chemicals have caused as much controversy as Bayer AG’s popular Roundup weedkiller. Defenders say it’s helped to feed the world by transforming farm yields. Opponents contend that the product’s key ingredient glyphosate poses unacceptable environmental and health risks. When the European Union decided to renew its approval for glyphosate for another 10 years in November, member states were divided on the issue and new conditions were imposed on its use. Meanwhile, Bayer continues to fight court cases against former Roundup users who say it caused their cancer.

In use for almost five decades, glyphosate is present in hundreds of pesticides. Agriculture accounts for the bulk of global demand, though home gardeners use it too. The chemical is mainly used to combat weeds but also helps crops dry and ripen. The dead weeds are no longer available to insects and other small animals as a habitat and source of food, which affects biodiversity. As usage has soared, traces of the chemical have been found in foods including breakfast cereals and cookies, while residues have also been detected in water, soil, drinks and human urine. Glyphosate accounted for one-third of the total herbicide market in the EU in 2017, the most recent year available. Bayer insists the product is safe.