OMRI (Organic Inputs — U.S.)

OMRI evaluates heavy-metal content as part of its organic input review.

Metals that must be submitted:
Arsenic (As), Cadmium (Cd), Lead (Pb)

Maximum Concentrations of Elemental Contaminants (ppm)

Products that are or contain:

Compost, Manure, Mulch, and Transplant Container Media (CF/CT), and Mulch for Use as Crop Weed Control (CP)
Arsenic (As):
• Caution statement at 10 ppm
• Cannot be listed at 149 ppm

Cadmium (Cd):
• Caution statement at 20 ppm
• Cannot be listed at 40 ppm

Lead (Pb):
• Caution statement at 90 ppm
• Cannot be listed at 290 ppm

Mined Minerals, Soil, and Ash (CF/CT)
Arsenic (As):
• Caution statement at 20 ppm
• Cannot be listed at 300 ppm

Cadmium (Cd):
• Caution statement at 40 ppm
• Cannot be listed at 80 ppm

Lead (Pb):
• Caution statement at 180 ppm
• Cannot be listed at 580 ppm

Notes:
• “Caution statement” indicates the level at which OMRI issues a caution on the OMRI Products List due to potential long-term soil contamination from elemental contaminants.
• “Cannot be listed” indicates the level at which a product is ineligible for listing on the OMRI Products List due to the risk of soil contamination.
• OMRI may require heavy-metal analysis for other materials depending on the recommended application rate.