DuPont used to produce sulfluramid in the U.S., where it was sold in products marketed to kill ants, roaches, and termites. New York banned sulfluramid in the 1990s. And in 2001, when the state levied the largest penalty in its history against a company distributing a sulfluramid-containing pesticide, the New York attorney general noted that “if a child ingested the bait, he or she could suffer irreversible reproductive damage, and boys could be rendered infertile.” In 2008, DuPont voluntarily canceled its registration of the chemical.

The ongoing use of sulfluramid in Brazil despite widespread knowledge of its dangers shows just how difficult it is to control the entire family of toxic chemicals to which PFOS belongs. Those chemicals, known as PFAS, now pollute water around the world. While delegates of the Stockholm Convention will be debating how to close the loopholes around PFOS and whether to enact a global ban on the closely related chemical PFOA, well over 1,000 other PFAS chemicals are still in active use.