Heavy metals testing for fertilizer registration: which states require it

As of October 2026, California, Oregon and Washington require a heavy-metals lab analysis to register a fertilizer, and all three post the results publicly. Minnesota won't register any fertilizer with more than 500 ppm arsenic and asks you to certify compliance. Idaho asks for metals data on waste-derived fertilizers, Utah's registration form asks for a metals report (clearly for waste-derived products, less clearly for others), and Florida sets metal limits without a routine filing requirement we could confirm. If you sell into all three western states, one well-specified lab report per product, paired with a metals statement on the label, covers most of the work.

Where the limits come from

The Association of American Plant Food Control Officials (AAPFCO) is the body of state fertilizer regulators that writes the model fertilizer law. Its Statement of Uniform Interpretation and Policy #25, the "Heavy Metal Rule," treats a fertilizer that guarantees phosphate or micronutrients as adulterated when it contains more than set levels of nine metals: arsenic, cadmium, cobalt, lead, mercury, molybdenum, nickel, selenium and zinc.

The limits scale with the product. You multiply the guaranteed percentage of P2O5 (with a floor of 6), or the total guaranteed micronutrients (with a floor of 1), by a per-percent value for each metal, and use the higher result. AAPFCO notes that many states have adopted metals standards, some require analyses to prove compliance, and three post the submitted analyses online: California, Oregon and Washington.

State requirements at a glance

Because Utah's form is ambiguous, ask the department whether your products need a report. Iowa's Department of Agriculture and Land Stewardship says it may ask for a heavy-metals analysis with a registration. Florida's Rule 5E-1.026 (amended January 2026) sets adulteration levels for the same nine metals as AAPFCO, but the rule text we read sets no routine lab-report filing.

California

Under California's rules (3 CCR 2302 and 2303), a product that guarantees iron, manganese, zinc or phosphates from inorganic sources must carry a metals statement. The statement points buyers to a toll-free number or a website. The California Department of Food and Agriculture (CDFA) calls the AAPFCO metals address (www.aapfco.org/metals.html) the most uniform choice across states. If your label uses it, you must submit a lab analysis whether or not the product contains those nutrients. The analysis must:

• report all nine metals: arsenic, cadmium, cobalt, copper, lead, mercury, molybdenum, nickel and selenium (required since January 1, 2021)
• be no more than 5 years old at registration or renewal, with a new analysis if the old one has aged out by renewal
• use sample preparation method 3050B or 3051 and the analytical methods in EPA publication SW-846.

California limits arsenic, cadmium and lead. These figures come from CDFA's labeling aid (revised August 2019); a 2020 CDFA notice said the limits had not changed:

• Specialty fertilizers guaranteeing 6% or more P2O5: for each 1% of P2O5, no more than 2 ppm arsenic, 4 ppm cadmium and 20 ppm lead.
• Products guaranteeing iron, manganese or zinc: for each 1% of those nutrients, 13 ppm arsenic, 12 ppm cadmium and 140 ppm lead.
• Specialty fertilizers under 6% P2O5 with no micronutrient claim: flat limits of 10 ppm arsenic, 20 ppm cadmium and 100 ppm lead. Under 6% P2O5 with a micronutrient claim, you add the per-percent micronutrient values to those flat limits.

For a 4-lb bag of 10-10-10, that works out to 20 ppm arsenic, 40 ppm cadmium and 200 ppm lead. For more on California's process, see the California fertilizer registration guide.

Oregon

Every fertilizer product sold in Oregon is registered, and the first application, sent by mail, fax or hand delivery, must include a lab report. The report gives total arsenic, cadmium, lead, mercury and nickel, from analyses done within the last 18 months. The lab's detection limits must be at or below 10.0 ppm arsenic, 5.0 ppm cadmium, 5.0 ppm lead, 0.20 ppm mercury and 5.0 ppm nickel (OAR 603-059-0070). The Oregon Department of Agriculture (ODA) is clear that these are reporting limits, not product limits.

The product limits are in OAR 603-059-0100. For each 1% of guaranteed P2O5, a product may contain up to 9 ppm arsenic, 7.5 ppm cadmium, 43 ppm lead, 0.7 ppm mercury and 175 ppm nickel, using at least 6 as the multiplier. Products with no phosphate or micronutrient guarantee have fixed limits of 54, 45, 258, 4.2 and 1,050 ppm.

So a 10-10-10 may contain up to 90 ppm arsenic, 75 ppm cadmium, 430 ppm lead, 7 ppm mercury and 1,750 ppm nickel. A 2-1-1 houseplant food falls back on the multiplier of 6, which gives the same 54/45/258/4.2/1,050 ppm limits.

Oregon labels must also carry a metals statement (OAR 603-059-0055), and ODA posts each product's arsenic, cadmium, lead, mercury and nickel levels publicly.

Washington

The Washington State Department of Agriculture (WSDA) requires a metals lab report for each product with every new registration. The report must show the sample preparation method, the analysis method, units (ppm or mg/kg), minimum detection limits and the level of each metal detected. The only exemptions are anhydrous ammonia products, customer-formula mixes, and repackaged single compounds (such as urea or MAP) that the supplier has already registered in Washington and you don't blend.

Washington's standard works differently from California's and Oregon's. WAC 16-200-7064 caps how much of each metal a product may add to soil per acre per year, based on Canadian standards:

Because the test depends on your application rate, WSDA provides a heavy-metals calculator. Its guidance warns that products with low nutrient guarantees, common among organic-based fertilizers and hydroponic or continuous liquid feed products, may need lower detection limits. Molybdenum and selenium commonly fail because a lab's detection limit is too high. You may report values higher than your lab found, but not lower. WSDA posts the data in its public product database.

Minnesota

Minn. Stat. 18C.401 bars registering any fertilizer with more than 500 ppm arsenic. The Minnesota Department of Agriculture (MDA) publishes two versions of how it checks:

• Its arsenic page says every application needs an arsenic self-certification, and that lab verification is required at initial licensing and registration, and again when raw materials or sources change. No report is needed at renewal if the formula hasn't changed.
• Its licensing FAQ says arsenic reports are no longer required with applications. You certify instead, keep the reports on file, and MDA may audit.

Treat this as unresolved and ask MDA which applies to your product. Separately, since January 1, 2026, specialty registrations must declare whether each product has more than 500 ppm arsenic, intentionally added PFAS, or genetically engineered organisms.

How to prepare

1. Map which products need testing. Anything sold into California, Oregon or Washington needs a report. So may any product with waste-derived ingredients sold into Idaho or Utah.
2. Order one panel that covers all three states. California's nine metals plus zinc for Washington covers Oregon's five too: arsenic, cadmium, cobalt, copper, lead, mercury, molybdenum, nickel, selenium and zinc. Test each formulation separately and put the product name on each report.
3. Specify methods and detection limits up front. Ask for EPA SW-846 methods with 3050B or 3051 preparation for California, detection limits at or below Oregon's, and limits low enough to pass the WSDA calculator. WSDA notes mercury needs a separate test.
4. Mind the clock. Oregon's 18-month window is the tightest. A report that meets it also works for California's 5 years.
5. Run the numbers before you print. Check results against the California and Oregon formulas above and the WSDA calculator.
6. Put a metals statement on the label. CDFA calls the AAPFCO address the most uniform option, and Oregon accepts it too. See fertilizer label requirements.
7. Retest when ingredients change. A new phosphate or micronutrient source can change metal levels, and Idaho and Minnesota tie new reports to source changes.

Registration basics for the three testing states:

These are the published requirements as of October 2026. Confirm with each agency before you test or file. The wider process is covered in how to register fertilizer in every state.

Sources

• AAPFCO Non-Nutritive/Heavy Metals, SUIP #25 and Metal Content Analysis Information
• CDFA Conventional Fertilizing Materials Licensing, Registration and Labeling Guide (Rev. 05.26.26)
• CDFA Heavy Metals Labeling Aid and Non-Nutritive Standards (Rev. August 2019)
• CDFA Notice to Industry: Heavy Metal Analysis for Fertilizing Materials (August 12, 2020)
• ODA: How do I register a fertilizer product in Oregon?
• OAR chapter 603, division 59, Oregon fertilizer rules (0055, 0070, 0100)
• WSDA Metal Analysis and WSDA Fertilizer Product Registration
• WAC 16-200-7064, Washington standards for metals
• WSDA Fertilizer Registration Guidance Document
• Minn. Stat. 18C.401, MDA Arsenic Concentration Limits in Fertilizer, MDA Fertilizer Licensing FAQs and MDA Specialty Fertilizer Registration
• Fla. Admin. Code R. 5E-1.026
• Idaho Code § 22-605
• Utah Department of Agriculture and Food fertilizer registration form
• IDALS: Distributing a Fertilizer or Soil Conditioner in Iowa