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HS Heading 3913 : Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms

HEADING DEFINITION & DISAMBIGUATION

HS Heading 3913 encompasses natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms. It classifies 2 6-digit WCO subheadings within Chapter 39 under the Harmonized System [USITC HTS 2026].

Chapter

Ch 39

Heading

3913

Subheadings

2 HS6

Status

Verified 2026

Subheadings Under Heading 3913

HS Code	WCO 6-Digit Subheading Description	Chapter	Operational Package
3913.10	Alginic acid, its salts and esters	39	View 3913.10 Package →
3913.90	Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms, Other	39	View 3913.90 Package →

DISAMBIGUATION & CLASSIFICATION GUIDE

How to Select the Correct Subheading Under Heading 3913

Commercial shipments must be declared under the exact 6-digit WCO subheading that matches physical, chemical, or processing characteristics. Review the subheading descriptions above and verify against binding CBP CROSS rulings prior to entry filing.

Official Primary Sources & Authority References

USITC HTS Heading 3913 ↗

United States International Trade Commission official Harmonized Tariff Schedule.

CBP CROSS Rulings ↗

CBP e-Rulings database for Heading 3913 precedent rulings.

WCO Nomenclature ↗

World Customs Organization Harmonized System 2022 nomenclature standard.

U.S. Census Foreign Trade ↗

U.S. Census Bureau HTS-to-NAICS concordance and Schedule B export database.

Heading 3913 Frequently Asked Questions (FAQ)

What commercial articles are grouped under HS Heading 3913?

HS Heading 3913 covers Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms, grouping 2 6-digit WCO subheadings.

How are 6-digit subheadings structured under Heading 3913?

Subheadings under Heading 3913 range from 3913.11 to 3913.90, classifying goods by processing state, origin, or material composition.

What is the representative US import duty rate for Heading 3913?

US MFN general duty rates for Heading 3913 commodities range from Duty-Free up to representative ad valorem percentages under the 2026 US HTS.

Are Section 301 tariffs applicable to goods under Heading 3913?

Section 301 additional tariffs depend on the specific 8-digit or 10-digit US HTS code and country of origin (e.g. China Lists 1–4A).

What PGA message set flags apply to Heading 3913?

Partner Government Agency flags (FDA, USDA APHIS, EPA) apply depending on the specific commodity sub-classification.

How do I distinguish between subheadings under Heading 3913?

Review WCO subheading terms and candidate descriptions. For example, unroasted vs. roasted or decaffeinated vs. non-decaffeinated.

Can goods under Heading 3913 enter duty-free under USMCA?

Yes. Goods originating in USMCA territories (US, Mexico, Canada) enter duty-free under SPI code P with a valid Certificate of Origin.

What is the Section 321 de minimis limit for Heading 3913?

Eligible import shipments valued at $800 USD or less imported by one person on one day enter duty-free under 19 U.S.C. 1321.

What documents are required for formal customs entry of Heading 3913?

Commercial Invoice, Packing List, Bill of Lading, and CBP Form 7501 are mandatory for entries exceeding $2,500 USD.

How can an importer get a binding CBP classification ruling for Heading 3913?

Importers may apply for a binding ruling via CBP National Commodity Specialist Division under 19 CFR Part 177.