I know there are some heavy metals still left in Milorganite, and also some prescription drug residue, but it is very little, and is constantly monitored. The huge reduction in heavy metals was accomplished way back in the early 1980's with new processing methods. So there is no need for a special bag any more, all Milorganite has had the great majority of heavy metals removed.
Blood meal, bone meal...are they monitored for drug residue? Aren't animals these days pumped full of all sorts of drugs and wouldn't those be residual in them also?
http://www.milorganite.com/usi...