Originally Posted by Smallaxe
I heard there was a chemical that could persist for a year or so if it was to contaminate compost,,, but I can't remember what it was...
Missed this earlier. I think you're thinking of Clopyralid, which is in Millennium Ultra II. Riggle schooled me on that in the gentlest of ways when I was new here. It is not labeled for lawns and I don't do lawns, so I was unfamiliar and unconcerned with the distinction.
DOH! I now see clopyralid is in Confront too. I have never used Confront. ProStreet had it right.