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October 17, 2026
Marine Pollutants Explained: When "Environmentally Hazardous" Actually Matters for Shipping
"Marine pollutant" and "environmentally hazardous substance" are two of the most common entries in Section 14 of a Safety Data Sheet — and two of the most commonly misunderstood. The classification is real, but for most products shipped in consumer-size containers, a set of exceptions means it has no effect on how the package ships.
Quick answer: A marine pollutant is a substance harmful to aquatic life, shipped under UN3082 (liquids) or UN3077 (solids) as Class 9. Under U.S. rules, marine pollutant requirements don't apply to non-bulk packages moving by highway, rail or air. And under the U.S. rules, the IMDG Code and the IATA regulations, marine pollutants in inner containers of 5 L or 5 kg or less are generally excepted in every mode — as long as the product has no other hazard and the packaging meets general requirements.
Important: informational only — not compliance advice
This article is written to help shippers understand how hazmat classification works and where it commonly goes wrong. It is not legal, regulatory or compliance advice, and it is not a substitute for hazmat training or for a classification by a qualified professional.
Classification depends on your exact formulation, packaging, quantity and transport mode. Always confirm with the official sources — PHMSA and 49 CFR Parts 171–180, the IMDG Code for vessel, the IATA Dangerous Goods Regulations for air, USPS Publication 52 for mail — and with your carrier and a qualified hazmat professional before you ship.
What Is a Marine Pollutant?
A marine pollutant is a material that is harmful to the aquatic environment — toxic to fish, invertebrates or algae, often with long-lasting effects. The concept comes from MARPOL Annex III, the international convention on preventing pollution from ships, which is why the rules are strictest for ocean transport.
When a marine pollutant has no other hazard, it ships as Class 9 (miscellaneous) under one of two entries:
- UN3082 — Environmentally hazardous substance, liquid, n.o.s.
- UN3077 — Environmentally hazardous substance, solid, n.o.s.
If the material is also flammable, corrosive or toxic, it ships under that primary hazard instead, with the marine pollutant status noted on top.
Two Ways a Product Becomes a Marine Pollutant
This is where a lot of the confusion starts, because U.S. domestic rules and international rules decide the question differently.
| U.S. domestic (49 CFR) | International (IMDG Code / IATA) | |
|---|---|---|
| How it's determined | By a list: Appendix B to 49 CFR 172.101 names the marine pollutants | By criteria: aquatic toxicity data for the substance or mixture |
| Mixtures | A mixture counts if it contains 10% or more by weight of a listed marine pollutant, or 1% or more of a "severe" one (marked PP) | Assessed from each ingredient's toxicity and concentration; very toxic ingredients can make a mixture qualify even at low concentrations, unless testing the mixture shows otherwise |
| Practical effect | Many products aren't marine pollutants under U.S. rules at all | The same product may qualify internationally |
That split explains why an SDS — often written to the international standard — can label a product UN3082 when it isn't a marine pollutant for a U.S. domestic shipment. In one recent catalog review of fragrance oils, the products checked contained ingredients that meet the international criteria, but none contained a marine pollutant from the U.S. list. (We walk through that example in Your SDS Isn't Your Shipping Classification.)
The Exceptions That Matter
| Rule | What it says | Where it applies |
|---|---|---|
| 49 CFR 171.4(c)(1) | Marine pollutant requirements don't apply to non-bulk packagings transported by motor vehicle, rail car or aircraft — unless any part of the trip is by vessel | U.S. domestic highway, rail and air |
| 49 CFR 171.4(c)(2) | Single or combination packagings with 5 L or less (liquids) or 5 kg or less (solids) per single or inner packaging aren't subject to other requirements, if the packaging meets the general requirements of 49 CFR 173.24 and 173.24a | U.S., all modes including vessel |
| IMDG Code 2.10.2.7 | Marine pollutants in single or combination packagings of 5 L / 5 kg or less per single or inner packaging aren't subject to the Code's marine pollutant provisions, if packaging general provisions are met | International ocean |
| IATA Special Provision A197 | UN3082 and UN3077 in single or inner packagings of 5 L / 5 kg or less may ship as not restricted, if packaging general provisions are met | Air |
In practice, most e-commerce products — bottles, jars, tubes and pouches well under 5 L — fall inside these exceptions.
When the Exception Does Not Help
- The product has another hazard. The exception removes the marine pollutant requirements only. A flammable marine pollutant is still a Class 3 flammable liquid, with everything that entails.
- Containers are larger than 5 L / 5 kg. Drums, pails, totes and bulk containers are regulated — and by vessel, they're fully regulated as marine pollutants.
- It's a hazardous waste or hazardous substance. Under 49 CFR 171.4(c)(2), the small-package exception doesn't apply to marine pollutants that are also a hazardous waste or a hazardous substance.
- The packaging isn't up to standard. The exceptions still require packaging that meets the general requirements — closed, leak-tight and strong enough for transport.
- You're importing in bulk. If you bring product in by ocean in large containers and repack it into retail sizes, the inbound leg is regulated even if your outbound parcels aren't.
What It Means for Your Shipping Costs
If a SKU is flagged UN3082 or UN3077 in your shipping software but ships in an excepted container size with no other hazard, you may be paying hazmat surcharges and accepting service restrictions you don't need — at 2026 list rates, $58.00 per package for fully regulated UPS Ground hazmat and $57.25 at FedEx Ground. See the hazmat shipping basics guide for the full fee table and carrier restrictions.
The fix isn't to unflag products on your own judgment. It's to get a documented classification for each SKU as you actually ship it, then set up your systems to match. If you want to see what misapplied surcharges are costing you, a carrier invoice audit will show it.
The Marine Pollutant Mark
When the rules do apply, packages carry the marine pollutant mark: a triangle showing a fish and a tree. It's a mark, not a hazard label, so it appears alongside any class labels the product requires. If your products fall within the exceptions above, the mark isn't required.
Frequently Asked Questions
What is a marine pollutant?
A substance harmful to the aquatic environment. When it has no other hazard, it ships as Class 9 under UN3082 (liquid) or UN3077 (solid), "Environmentally hazardous substance, n.o.s." U.S. rules identify marine pollutants by a list in Appendix B to 49 CFR 172.101; international rules use aquatic toxicity criteria.
Are marine pollutants regulated when shipped by ground in the U.S.?
Generally not in non-bulk packaging. Under 49 CFR 171.4(c)(1), the requirements specific to marine pollutants don't apply to non-bulk packagings transported by motor vehicle, rail or aircraft, unless part of the trip is by vessel. Any other hazard the product has still applies.
What is the 5 L / 5 kg marine pollutant exception?
Marine pollutants in single or inner packagings of 5 L or less (liquids) or 5 kg or less (solids) are generally excepted under 49 CFR 171.4(c)(2), IMDG Code 2.10.2.7 and IATA Special Provision A197, provided the packaging meets general requirements. It doesn't apply to other hazards, or (under U.S. rules) to hazardous wastes or hazardous substances.
Why does my SDS say UN3082 if the product isn't regulated?
The SDS often reflects the international classification and the worst case — bulk quantities by vessel. It usually doesn't account for the small-package exceptions or for the different U.S. definition. Have the classification confirmed for your specific packaging and mode.
What does the marine pollutant mark look like?
A triangle showing a fish and a tree. It is a mark rather than a hazard label and is required only when the marine pollutant rules apply to the package.
Related Reading
- Your SDS Isn't Your Shipping Classification: How Misclassified Products Cost Shippers Money
- How to Ship Hazmat: Is Your Product Hazardous, and What It Limits (2026)
- FedEx Surcharges 2026: Every Fee, Rate & Threshold Explained
- UPS 2026 Rate Increase: Complete Guide to Every Service and Surcharge Change
Disclaimer: informational only — always verify with official sources
This article is provided for general informational purposes only. It does not constitute legal, regulatory, compliance or safety advice, and it is not a substitute for required hazmat training. D'Arrigo Consulting is not affiliated with UPS, FedEx, USPS, PHMSA, the IMO, IATA or any government agency, and does not provide hazmat classification services.
Regulatory references include 49 CFR 171.4, 171.8 and Appendix B to 172.101, the IMDG Code (2.10.2.7) and IATA Special Provision A197 as understood at the time of writing. International editions are amended on a regular cycle, so check the current IMDG Code and IATA Dangerous Goods Regulations. Carrier figures are 2026 list rates from the UPS Rate and Service Guide and FedEx Service Guide, before fuel and contract pricing.
Before shipping any hazardous material, confirm every requirement with the official sources and your carrier. Classification and shipping decisions are the shipper's legal responsibility. If you are unsure, consult a qualified hazmat professional. Have questions? Reach out to us — we're happy to help.
Meet the Author
paul@darrigoconsulting.com
I’m Paul D’Arrigo. I’ve spent my career building, fixing, and scaling operations across eCommerce, fulfillment, logistics, and SaaS businesses, from early-stage companies to multi-million-dollar operators. I’ve been on both sides of growth: as a founder, an operator, and a fractional COO brought in when things get complex and execution starts to break
