Hawaii used to restrict all 2,4-D sold in units over 1 QT or equal to it. Funny thing was, straight MCPP, triclopyr, or dicamba was never restricted. I remember lots of people buying Trimec by the pint or quart to get around that. Fortunately, the DOA came to their senses and pulled their stick out from where the sun don't shine. I do not see what harm can happen with 2,4-D in the hands of a responsible applicator. Then again, very few people know what it is anymore. I am one of the few, because my grandfather was a farmer and he used it on brush and vines.