There are a number of experts including pond management companies and fisheries who throw inflammatory words around about Diuron like carcinogen. I recocognize that the use sheets for Diuron do not include ponds and therefore it is not approved for ponds. That is in the USA. The use sheets in Canada specifically call out use on ponds. So there it is ok. A few years back MIssissippi got an exemption from the EPA to use it in catfish farm ponds where they raise the fish for consumption. Compare the Diuron Data Safety Sheets to Cutrine and see which is more dangerous. Except in CA (prop 64) neither chemical is listed as a carcinogen, both are in CA. The fish toxicity is a higher for Cutrine. So be cautious of scare tactics by those who don't know or those that have a vested interest in convincing you that you committed an awful health travesty.