I had my commercial herbicide/pesticide license for years. I had no need for it anymore so I left it expire. Forgot much of it.
I’ll never forget using atrazine to kill the grass along the driveway and it rained, killing a much wider area than I expected.
Or finding out that crappie bass were highly allergic to copper sulfate and they all went through the overflow pipe to escape it.
School of hard knocks learning.
Atrazine.
Yep. I remember run off problems with it when I was a kid. The popular thing to do then was to top dress the corn and sorghum with a mix of atrazine and “28” nitrogen.
Atrazine is still widely-used in the US.