Well, the way the response reads to me, it looks like Milorganite gets the lion's share of iron for their product from outside vendor(s), Smallaxe. ____________________________________________________ My question, as it was e-mailed to Milorganite: "Is the 4% iron content in Milorganite a direct by-product of the sewage that enters the pipes of the MMSD, or is it purchased from an outside vendor and added as a component sometime along the processing line?" This is the exact response I got from Milorganite today: "Thanks for taking the time to contact us. We do add iron to Milorganite, the full 4% is not a by-product of the treatment process. Please feel free to contact me with any other questions." Jaime Staufenbeil Agronomist Milorganite email@example.com __________________________________________________________ This sort of makes sense, too, because the stuff I've read about the HISTORY of Milorganite going back to the early 20th century shows nothing whatsoever about iron being included. I'll bet 'cha a hot fudge sundae they started adding iron only a few decades ago as a perceived marketing advantage to maybe help them keep ahead of their chemical & non-chemical competition a little better on the garden center shelves. I wont rub it in TOO much, but now at least we all know a X% leading up to 4% of Milorganite doesn't originate from the crappers of Milwaukee!