6 of 10 required analytes carry a numeric human-grade limit. Controlled without a numeric human-food maximum: Nickel (Ni), Aluminium (Al). Not material in this matrix: Tin (Sn), Hexavalent chromium (Cr-VI). A controlled analyte is measured on every lot with no defensible human-food number to anchor to; regulatory silence does not establish immateriality, and each not-material determination is registered and evidence-tested. This is the honest state of the science for this matrix, not a certification-readiness gap to hide.
How every number on this page is set
Pet food is legally governed by feed law — the EU’s Directive 2002/32 on undesirable substances in animal feed, the US FDA Center for Veterinary Medicine’s guidance, and the AAFCO model regulations, with enforced pet-food maxima in Japan and draft maxima in China. Those feed limits are generally far laxer than the limits the same governments set for human food. Heavy Metal Tested & Certified does not certify to the feed limit. For each analyte, the standard is the strictest maximum level a credible government sets for the nearest human food, adopted voluntarily as a human-grade over-compliance and stated in Fish-based / marine-protein complete diets’s own as consumed basis.
This is an intentional over-compliance, and it is disclosed as one. Every row below shows the feed-law floor the product is legally allowed to meet, and the tighter human-food limit HMTc certifies to instead. That honesty is the point: a certified pet food is held to the maximum levels that govern food for people, not the looser levels that govern feed for animals. Where the nearest human food is itself unregulated for an analyte, the standard does not invent a number: the analyte is a mandatory-tested control, or a registered, evidence-tested not-material determination.
Basis is never conflated. A dry product (kibble, semi-moist, freeze-dried, treats, chews) reads across only from dry human foods as sold; a wet product (canned, raw, broths, milk replacers, fish diets) only from human foods as consumed. No wet-to-dry conversion is performed, and where a human analog is published on a more concentrated basis than the pet product the adopted value is conservative, never loosened.
Master Limit Table
All values in ppb (µg/kg). Every numeric cell is the strictest human-food sovereign maximum for the nearest analog, adopted as the human-grade limit. A brand meeting every value qualifies for the mark.
| Analyte | Tier | HMTc limit | Basis |
|---|---|---|---|
| Lead (Pb) | Tier 1 | 200 | human-grade read-across (Fiji) |
| Cadmium (Cd) | Tier 1 | 50 | human-grade read-across (Gulf (GSO)) |
| Total arsenic (tAs) | Tier 2 | 1,000 | human-grade read-across (Paraguay) |
| Inorganic arsenic (iAs) | Tier 1 | 100 | human-grade read-across (European Union) |
| Mercury, total (tHg) | Tier 1 | 300 | human-grade read-across (European Union) |
| Methylmercury (MeHg) | Tier 1 | ≤ tHg | bounded by total mercury |
| Nickel (Ni) | Tier 2 | control | controlled — no human-food maximum (see note) |
| Tin (Sn) | Tier 2 | n/m | not material in this matrix (see note) |
| Aluminium (Al) | Tier 2 | control | controlled — no human-food maximum (see note) |
| Total chromium (Cr) | Tier 2 | 12,000 | human-grade read-across (India) |
| Hexavalent chromium (Cr-VI) | Tier 2 | n/m | not material in this matrix (see note) |
Tier 1 (Pb, Cd, iAs, mercury) are zero-tolerance toxics with no established safe threshold. Tier 2 (tAs, Ni, Sn, Al, chromium) carry a 150% transitional allowance under the program’s Status A–E framework. Total arsenic and total mercury operate as reflex screens to their toxic species (iAs, MeHg). Hexavalent chromium reduces to Cr(III) in the food matrix and is bounded by total chromium. “control” means measured every lot with no defensible human-food number; “n/m” is a registered not-material determination.
Feed law is the floor. HMTc certifies to human food.
The table below is the whole argument for the mark, stated plainly. The left column is the maximum a pet food is legally allowed to contain under feed law. The right columns are the tighter human-food limit HMTc certifies to instead, and the human food that limit comes from. The gap between them is the voluntary over-compliance a brand earns by certifying.
| Analyte | Feed-law floor (µg/kg) | HMTc human-grade limit | Over-compliance | Nearest human food |
|---|---|---|---|---|
| Lead (Pb) | 5,000 (Japan FAMIC, EU 2002/32, China (draft)) | 200 | 25× tighter | marine non-predatory finfish and forage fish sold for human consumption |
| Cadmium (Cd) | 2,000 (Japan FAMIC, EU 2002/32, China (draft)) | 50 | 40× tighter | marine non-predatory finfish and forage fish sold for human consumption |
| Total arsenic (tAs) | 10,000 (EU 2002/32, China (draft)) | 1,000 | 10× tighter | marine non-predatory finfish and forage fish sold for human consumption |
| Inorganic arsenic (iAs) | 2,000 (China (draft)) | 100 | 20× tighter | marine non-predatory finfish and forage fish sold for human consumption |
| Mercury, total (tHg) | 1,000 (China (draft), EU 2002/32) | 300 | 3.3× tighter | marine non-predatory finfish and forage fish sold for human consumption |
| Nickel (Ni) | no feed limit set | control | no human-food maximum | |
| Tin (Sn) | no feed limit set | n/m | not material | |
| Aluminium (Al) | no feed limit set | control | no human-food maximum | |
| Total chromium (Cr) | 5,000 (China (draft)) | 12,000 | at or below floor | marine non-predatory finfish and forage fish sold for human consumption |
Feed-law floor is the least strict of the applicable feed maxima (EU Directive 2002/32 complete/compound pet feed; Japan FAMIC pet-food standard; China draft pet-food guidance), stated for the strongest honest contrast. It is disclosed, never used to set the HMTc number. “No feed limit set” means feed law leaves the analyte unregulated, so the human-grade limit is not a reduction from a floor but a limit where feed law has none.
Derivation — where each number comes from
Every cell traces to one named sovereign human-food maximum level (the strictest for the nearest analog), or to an explicit control / not-material determination. No occurrence statistic and no feed limit selects a certification value.
| Analyte | HMTc | Human-food analog / determination |
|---|---|---|
| Lead (Pb) | 200 | Fiji — Muscle meat of fish, excluding those listed below |
| Cadmium (Cd) | 50 | Gulf (GSO) — Muscle meat of fish with exception mentioned |
| Total arsenic (tAs) | 1,000 | Paraguay — raw, frozen, or refrigerated fish |
| Inorganic arsenic (iAs) | 100 | European Union — muscle meat of fish, species other than those listed under Annex I 3.4.5.2 |
| Mercury, total (tHg) | 300 | European Union — listed lower-mercury fish and cephalopods/marine gastropods, including cod, herring, mackerel, salmon/trout species listed, sardine/pilchard, sole, whiting, and others |
| Methylmercury (MeHg) | ≤ tHg | Methylmercury is a component of total mercury (MeHg ≤ tHg). No human-food analog sets a methylmercury limit below the binding total-mercury read-across (300 µg/kg), so methylmercury is governed by and bounded by the total-mercury ceiling; no separate methylmercury ceiling is published. |
| Nickel (Ni) | control | No government sets a nickel maximum for finfish; total nickel is measured on every lot as a mandatory surveillance control. |
| Tin (Sn) | n/m | Tin is a can-migration analyte; fresh, frozen, or refrigerated fish-based pet food has no tin source. Canned fish-based products are certified under the canned-wet tin read-across. |
| Aluminium (Al) | control | No government sets an aluminium contaminant maximum for finfish or general human foods; the only human-food aluminium numbers are permitted additive-residue limits, not contaminant maxima. Aluminium is measured on every lot as a mandatory surveillance control. |
| Total chromium (Cr) | 12,000 | India — All fishery products |
| Hexavalent chromium (Cr-VI) | n/m | Hexavalent chromium reduces to Cr(III) in the fish matrix; bounded by total chromium, measured on every lot. |
Source instruments
Two legal registers set this page. The human-food maximum levels below are the standards HMTc certifies to; the strictest for the nearest analog binds each analyte. The feed-law floor is disclosed for contrast and never sets a number.
Human-food maximum levels (the certification basis):
| # | Instrument | Type | Role in this standard |
|---|---|---|---|
| 1 | European Union human-food maximum levels | Maximum levels | Binds Inorganic arsenic, Mercury, total |
| 2 | Fiji human-food maximum levels | Maximum levels | Binds Lead |
| 3 | Gulf (GSO) human-food maximum levels | Maximum levels | Binds Cadmium |
| 4 | India human-food maximum levels | Maximum levels | Binds Total chromium |
| 5 | Paraguay human-food maximum levels | Maximum levels | Binds Total arsenic |
Feed-law floor (disclosed, not applied): EU Directive 2002/32/EC on undesirable substances in animal feed (complete and compound pet feed); Japan FAMIC pet-food standard (2021); China draft pet-food guidance. Every value weighed against these is shown in the human-grade table above.
The literature baseline for pet-food occurrence and for each analyte is maintained independently at the Heavy Metal Index. This certification standard applies those findings; the two are kept editorially separate by design.
Cite this standard
Pendergrass, K. “Fish-based / marine-protein pet diets.” In Heavy Metal Tested & Certified (HMTc) Pet Foods standard, version 1.0. Institute of Contaminant Standards (ICS), 2026. DOI: registration pending.
Version history
The dated editions of this standard. Each is kept at a stable permalink, so a regulator or brand can reconstruct exactly what the standard required on any date.
| Version | Date | Status | What changed |
|---|---|---|---|
| v1.0 | 2026-08-13 | current | Initial publication. Human-grade over-compliance (Method v2.0): pet food is legally feed, but every analyte is certified to the strictest human-food sovereign maximum for the nearest analog (as consumed basis), with the feed-law floor disclosed and never used to set a number. 6 of 10 analytes carry a numeric human-grade limit; the remainder are mandatory-tested controls or registered not-material determinations. |