Much has been made about the dangers of glyphosate - the main ingredient in Monsanto's Roundup, the world's best-selling herbicide.  But there's mounting evidence that some of the inert ingredients in Roundup and other glyphosate-based weedkillers may be dangerous as well.

Last year, the United Nations World Health Organization's International Agency for Research on Cancer (IARC) declared that glyphosate probably causes cancer in humans.  The group's report found an association between non-Hodgkin lymphoma and glyphosate, as well as significant evidence that the chemical caused cancer in lab animals.  WHO researchers also cited strong evidence that it damaged human DNA. 

Last year, a French study sounded the alarm on Roundup's "inert ingredients" who had previously escaped scrutiny.  At least six people in the US who have developed non-Hodgkin lymphoma are suing Monsanto over Roundup, claiming that Monsanto "knew or should have known that Roundup is more toxic than glyphosate alone and that safety studies of Roundup, Roundup's adjuvants and 'inert' ingredients" were necessary.

Europe is starting to name these inert ingredients.  Germany removed all herbicides containing chemical known as polyethoxylated tallowamine (POEA) from the market in 2014, after a forestry worker who had been exposed to it developed toxic inflammation of the lungs.  Last month, France took the first step toward banning products that combine glyphosate and POEA.  Shortly after that, the European Parliament passed a non-binding resolution in support of the POEA ban .

Monsanto says it already is segueing away from POEA-products, but these "products do not pose an imminent risk for human health when used according to instructions".