Other slag and ash — HTS 2621
Other slag and ash, including seaweed ash (kelp); ash and residues from the incineration of municipal waste
Chapter 26 › Heading 2621
2026 HTS Rev 19 Synced Rules verified Operational
Written to help non-specialists understand this page. Rates, dates, and legal facts come from the official records above and on the linked source.
HTS heading 2621 is a broad product category for certain types of slag and ash that are not covered by more specific headings in Chapter 26. It includes seaweed ash, such as kelp ash, and ash or residues produced by incinerating municipal waste. These goods are generally industrial or waste-processing materials rather than ordinary consumer products.
The 4-digit heading is only the starting point. To reach the correct 8-digit HTSUS code, identify the product’s exact composition, source, and physical form, then follow the applicable subheadings and statistical suffixes. The detailed subdivisions commonly distinguish the material or type of residue, so laboratory data, production records, and a clear description of how the goods were made may be important. Classification can depend on legal notes and exclusions elsewhere in the tariff, so unusual or mixed materials may require a customs broker or binding-ruling analysis.
What to check
- Confirm that the goods belong in heading 2621 rather than a more specific slag, ash, mineral, chemical, or waste heading.
- Identify the source and composition: for example, seaweed ash, municipal-waste incineration residue, or another type of slag or ash.
- Check whether the product is a single material, a mixture, or a processed product, and document any treatment such as sorting, washing, or recovery of metals.
- Use the current HTSUS subheading text and statistical suffix descriptions to match the material or residue type; do not stop at the 4-digit heading.
- Keep a technical specification, safety data sheet, production description, and test results, and ask a customs broker or request a binding ruling when the classification is uncertain.
HTS heading 2621 summary
Other slag and ash is a 4-digit product category containing 2 published product-code lines in this snapshot. A heading does not carry one universal duty rate; classification must be narrowed to the line matching the product facts.
How to find your code in this category
A heading is a product category. To get the exact duty, narrow from this 4-digit heading to a sub-category (usually by material), then open the 8-digit code that matches your product.
Open any code in the tables below to see its exact duty rate, a duty calculator (enter your shipment value → estimated duty and landed cost), the rate-change history chart, and the country-by-country breakdown (including Section 301/232 add-on duties).
Why you have to click in: a single category can contain products with very different duties. The rate depends on the specific product — its material and construction — and on the country of origin, and those only get pinned down at the 8-digit code level. That is why this page points you to codes instead of showing one rate for the whole category.
Product codes & duty rates
👇 Each row is a specific product code — click a blue code to open its full page with exact duty rates by country, the rate-history chart, and a duty calculator. 👉
| Code | Description | General (MFN) | Special | Column 2 |
|---|---|---|---|---|
| 2621.10.00.00 👉 | Ash and residues from the incineration of municipal waste | Free | — | Free |
| 2621.90.00.00 👉 | Other | Free | — | Free |
"Special" shows the free-trade-agreement rate; open a code to see exactly which countries qualify.
Common questions
What products fall under HTS heading 2621?
Other slag and ash, including seaweed ash (kelp); ash and residues from the incineration of municipal waste. To classify a specific item you must pick the matching sub-category and 8-digit code above; the right choice usually depends on the material and construction of the product.
How do I choose the right code within this category?
Start from the sub-categories (typically divided by material—for example cotton versus man-made fibers), then open the active 8- or 10-digit code that matches the product. When unsure, a licensed customs broker or a CBP binding ruling can confirm the classification.
Reference information only, not customs, legal, or classification advice. Confirm the current code and rate against the official HTS before you import.