Agree that paraquat and diquat are very nasty chemicals (the active in Sprayseed). I believe that when paraquat was formulated it had no odour but it was necessary to give it a very nasty smell to encourage users to be very careful when using it. Paraquat will kill you damn quick. I remember a veggie farmer who spilled some concentrate when filling a spray tank. It hit him in the mouth and he died later that night. Always read the label and use protective equipment when using any pesticide.