Marine pollutants are the quiet compliance trap of ocean export. The product may be perfectly ordinary — a paint additive, a marine antifouling agent, a pesticide concentrate, a metal-working fluid — and it may not be dangerous in any of the ways shippers normally think about. But if it is harmful to the aquatic environment, the IMDG Code regulates it, and a container full of it will be stopped if the paperwork and marking are missing.
For exporters moving freight out of PortMiami or Port Everglades to the Caribbean and Latin America, this comes up constantly. Here is how UN3077 and UN3082 work.
What is a marine pollutant?
Under the IMDG Code, a marine pollutant is a substance identified as harmful to the marine environment based on aquatic toxicity, bioaccumulation potential and degradability criteria. Two things follow from that definition and they are often confused:
- A material can be a marine pollutant and also belong to another hazard class. A flammable liquid that is also a marine pollutant ships as Class 3 with the marine pollutant mark added.
- A material can be a marine pollutant and nothing else. That is when UN3077 and UN3082 apply — the substance’s only transport hazard is environmental.
The two n.o.s. entries
| UN number | Proper shipping name | Class | Packing groups |
|---|---|---|---|
| UN3077 | Environmentally hazardous substance, solid, n.o.s. | 9 | III |
| UN3082 | Environmentally hazardous substance, liquid, n.o.s. | 9 | III |
Both are Class 9, both are Packing Group III, and both are “n.o.s.” — not otherwise specified — which means the technical name of the substance must appear in parentheses after the proper shipping name on the transport document. “UN3082, Environmentally hazardous substance, liquid, n.o.s., 9, III” is an incomplete entry. “UN3082, Environmentally hazardous substance, liquid, n.o.s. (contains tributyltin compounds), 9, III, MARINE POLLUTANT” is complete.
How to tell if your product qualifies
Start with the safety data sheet. Section 12 covers ecological information — aquatic toxicity values, persistence, bioaccumulative potential. Section 14 should carry a marine pollutant statement if the supplier has classified it, though in practice SDS quality varies widely and imported SDSs often omit it.
Two additional checks are worth making:
- The IMDG Code index of marine pollutants. The Code contains a list of substances identified as marine pollutants, including entries flagged as severe marine pollutants.
- GHS aquatic hazard classification. If the product carries the GHS environmental pictogram (the dead fish and tree) with H400, H410 or H411 statements, treat marine pollutant status as likely and verify rather than assume.
If your supplier cannot confirm it, do not guess in either direction. Declaring something as a marine pollutant that is not one causes unnecessary handling costs; failing to declare one that is is a violation. A classification review is a much cheaper way to resolve it than a terminal hold.
Marking and labelling requirements
For a UN3077 or UN3082 shipment you generally need:
- Class 9 hazard label on the package
- Marine pollutant mark — the black-and-white fish-and-tree symbol — on the package and, where required, on the container or transport unit
- UN number and proper shipping name marked on the package, with the technical name
- UN specification packaging tested to at least PG III performance
- Orientation arrows where the package contains liquids in inner packagings
For a container load, the marine pollutant mark goes on the container in addition to any placards, and the container packing certificate should reflect the contents accurately.
The limited quantity relief
Small inner packagings can qualify for limited quantity provisions, which relieve some of the marking and labelling burden. But the thresholds and the relief differ by mode — the IMDG Code, the IATA DGR and 49 CFR do not align perfectly. Do not carry an air limited-quantity assumption over to an ocean booking.
Where marine pollutant shipments actually go wrong
In our documentation work at the Miami desk, the recurring failures are consistent:
- Missing “MARINE POLLUTANT” on the transport document. The mark is on the box, but the notation is absent from the dangerous goods declaration.
- Missing technical name. Because UN3077 and UN3082 are n.o.s. entries, this is a hard requirement, and it is the single most common rejection reason we see.
- Domestic highway assumptions applied to export freight. U.S. domestic highway rules give relief for marine pollutants in non-bulk packagings that does not carry over to the ocean leg. Freight that moved legally unmarked from your dock to the port can still be non-compliant at the vessel.
- Container mark omitted. Packages marked correctly, container not marked at all.
- Wrong packaging. A non-UN-rated pail used because “it isn’t really hazardous.”
If you are exporting from South Florida and your marine pollutant freight is already packed and marked incorrectly, it is usually faster to fix it before the terminal than after. Our hazmat repacking service in Miami exists largely for exactly this situation, and our mobile hazmat documentation team can prepare corrected declarations on site.
A practical pre-booking checklist
- Confirm marine pollutant status from SDS Sections 12 and 14, cross-checked against the IMDG list
- Determine whether the material has another primary hazard class or ships as UN3077/UN3082
- Get the technical name in writing from the supplier
- Verify packaging is UN-rated to PG III or better and in good condition
- Apply the Class 9 label and the marine pollutant mark to every package
- Mark the container and include the notation on the dangerous goods declaration
- Confirm the carrier and destination country accept the entry — some Caribbean and Latin American ports apply additional national requirements
Frequently asked questions
Is a marine pollutant automatically a hazardous material by truck in the U.S.?
Not always. U.S. domestic highway regulations provide relief for marine pollutants in non-bulk packagings under certain conditions, so a shipment can move domestically without full hazmat treatment and still be fully regulated once it is tendered for ocean transport. If the freight is destined for export, prepare it to the IMDG requirement from the start.
Do I need the technical name if I use UN3077 or UN3082?
Yes. Both are “not otherwise specified” entries, which means the technical name of the substance that makes the material a marine pollutant must appear in parentheses immediately after the proper shipping name on the transport document. Omitting it is the most common reason these shipments are rejected.
What is a severe marine pollutant?
The IMDG Code distinguishes certain substances as severe marine pollutants based on stricter aquatic toxicity criteria. The transport requirements are broadly the same, but the classification affects some stowage and reporting provisions, and it should be identified accurately on your documentation.