STA Certified Compost - Test Result Limits for Compost Manufacturers
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STA Certified Compost participants must meet the EPA testing limits for heavy metals AND pathogens in every CTDS (Compost Technical Data Sheet) for every STA Certified Compost product.



Metals- maximum concentrations expressed on a dry weight basis (Chromium and Molybdenum do not have EPA limits)

Arsenic (As) 41 mg/Kg

Cadmium (Cd) 39 mg/Kg

Copper (Cu) 1500 mg/Kg

Lead (Pb) 300 mg/Kg

Mercury (Hg) 17 mg/Kg

Nickel (Ni) 420 mg/Kg

Selenium (Se) 100 mg/Kg

Zinc (Zn) 2800 mg/Kg



Pathogens- pass either Fecal Coliform or Salmonella, at the manufacturers choice.  Must pass both in California.


Fecal Coliform maximum concentrations

< 1000 MPN / gram of dry compost


Salmonella maximum concentrations

< 3 MPN / 4 grams of dry compost