Actually, if folks knew the degree to which fertilizer companies were allowed to dispose of toxic wastes in the fertilizers they produce, most would be flabergasted. As one simple example check this site
Metals in Fertilizers - Washington State Dept. of Agriculture - WSDA where metals (including toxic) that are allowed to be distributed in commercial fertilizers is discussed. In short, many of the commercial fertilizers used by folks here on this board, are used to get rid of certain toxic wastes. Some people still think "dillution is the solution to pollution". If we can dilute the pollutants far enough, no one will know.