Health Canada is sticking with its proposal to phase out most outdoor and agricultural uses of a common pesticide, even though a recent study found bees are only affected by the substance in certain circumstances.

The recommendation comes the same day as more than 200 scientists published an open letter in the journal Science asking international governments to develop agreements to not use so-called neonicotinoids and to prevent similarly harmful pesticides to be developed and used in the future.

In 2012, Canada’s Pest Management Regulatory Agency began studying nicotine-based pesticides known as neonicotinoids, commonly used by farmers and hobby gardeners to drive away pests like aphids and spider mites, after scientists linked them to high rates of honey bee deaths. The agency did multiple different evaluations of three different neonics and their impact on different organisms.

In 2016, it concluded one of the neonics, imidacloprid was building up in the surface and ground water and causing widespread death among aquatic insects.