Washington Dept of agriculture

Has the strictest citeria in the U.S.A.
THEY ARE considered as strict as canada on their fertilizer minerals testing.
They use a method that tells how much metal will collect within the soil, over a long period of time. IT TELLS A DIFFERENT STORY than most, it is not based on what is in the bottle- but what collects in the soil with time....

here is the site, it seems to go down a lot..
http://agr.wa.gov/PestFert/Fertilizers/default.htm

product search by name
http://agr.wa.gov/PestFert/Fertilizers/FertDB/Product1.asp

good huntin!