In 2019, Costco reportedly stopped selling Roundup weed killer, but now it’s back. What’s up with that?

The Roundup Costco sells now has an “Exclusive Formula” that Friends of the Earth says contains two ingredients banned in the European Union and is “45 times more toxic” than the glyphosate-based version (a potent carcinogen).

The two pesticides that are banned in the E.U., but sold at Costco in the new Roundup are diquat dibromide and imazapic.

Diquat dibromide is 200 times more toxic than glyphosate.

Diquat was banned in the E.U. in 2020 because of its acute and reproductive toxicity and the grave danger this posed to workers and anyone else who might be exposed to diquat sprays. European Food Safety Authority regulators found that even when workers wore coveralls, gloves, and boots, they were still exposed to three-and-a-half times the maximum acceptable level of diquat.

Diquat is a product of Syngenta, which was bought by ChemChina in 2017, but remains headquartered in Switzerland. It’s manufactured in the U.K. where it’s also banned. Despite the bans, diquat is exported to the U.S. and other countries.

This has been disastrous to the farmers of Brazil who have been plagued by diquat poisoning incidents since 2020 when diquat replaced its close cousin paraquat after that notoriously dangerous weed killer was banned in Brazil. As The Guardian reported, diquat is generally considered less toxic than paraquat, but can still be extremely harmful: exposure can lead to paralysis, blindness, vomiting, irritation, convulsions, organ damage and even death.

Imazapic is the other banned-in-the-E.U. pesticide in the new Roundup formulation sold at Costco. According to a 2003 fact sheet prepared by Caroline Cox for the Journal of Pesticide Reform, “Toxicological problems caused by imazapic and imazapic-containing herbicides in laboratory studies include eye irritation, muscle degeneration, liver damage, anemia, increased blood levels of cholesterol, and a birth defect called rudimentary ribs.” 

This does not bode well for people buying Roundup at Costco—who aren’t being warned of the product’s new dangers or how to protect themselves or others.

Tell Costco: Stop Selling Roundup! Costco doesn’t have a publicly available email address, so the best way to submit your feedback is to call your local Costco, or the online store at 1-800-955-2292, or to communicate with them via social media on Facebook, Instagram and Pinterest. For an easy, one-click action, like and share our posts on Facebook, X and Instagram.