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Home / Section VI / HS 28.31

HS 28.31

Heading

Dithionites and sulphoxylates

HS Code 28.31 classifies "Dithionites and sulphoxylates" under Section VI (Products of Chemical or Allied Industries). This heading-level code is used internationally for customs classification, tariff determination, and trade statistics.

Classification Details

HS Code28.31
DescriptionDithionites and sulphoxylates
LevelHeading (4-digit)
SectionVI — Products of Chemical or Allied Industries
Chapter28

🇺🇸 US Import Duty

Average Duty Rate2.5%
Duty Range0-6.5%
NotesInorganic chemicals
Free Trade AgreementsMost FTAs: 0%

Rates are approximate and based on MFN (Most Favored Nation) tariffs. Actual rates may vary by specific product classification. Always verify with USITC for official rates.

Classification Guide

When classifying goods under HS 28.31, ensure the product matches the specific description. This is a heading-level code. For customs declaration, you may need the more specific 6-digit subheading. Check with your national customs authority for additional digits required.

Trade Context

Section VI covers chemical and pharmaceutical products — a high-value trade sector.

Regulatory Note

Pharmaceutical imports often require regulatory approval (FDA, EMA). Chemical safety data sheets (SDS) are mandatory for most products.

🇺🇸 US Import Document Checklist

Documents required when importing products under HS 28.31 into the United States.

Required for All Imports

☑Commercial InvoiceCBP
Detailed invoice from the seller showing product description, quantity, unit price, total value, and terms of sale (Incoterms).
☑Packing ListCBP
Itemized list of contents in each package, including weights, dimensions, and marks/numbers matching the shipping containers.
☑Bill of Lading (B/L) or Airway BillCarrier
Transport document issued by the carrier confirming receipt of goods for shipment. Acts as a contract of carriage and receipt.
☑CBP Entry Summary (Form 7501)CBP
The formal customs declaration filed with US Customs and Border Protection for all commercial imports.
☑Importer Security Filing (ISF/10+2)CBP
Must be filed at least 24 hours before ocean cargo is loaded. Required for all ocean shipments to the US.
☑Customs BondCBP
A financial guarantee ensuring payment of duties, taxes, and fees. Required for commercial shipments over $2,500.

Product-Specific Requirements

⚠️TSCA Import CertificationRequired

Certify that imported chemicals comply with the Toxic Substances Control Act.

Agency: EPA

⚠️Safety Data Sheet (SDS)Required

16-section document describing chemical hazards, handling, and emergency procedures.

Agency: OSHA

📋EPA NotificationMay be required

New chemical substances may require EPA pre-manufacture notification.

Agency: EPA

FTA Certificate of Origin (for preferential rates)

🤝USMCA Certificate of Origin — self-certification by importer, exporter, or producer. No prescribed format.
🤝Korea-US FTA Certificate of Origin — can be issued by importer, exporter, or producer.

This checklist is for general guidance only. Actual requirements may vary based on specific product, country of origin, and current regulations. Always consult with a licensed customs broker or the relevant agency for official requirements.

Sub-Classifications

2831.10Dithionites and sulphoxylates; of sodiumSubheading2831.90Dithionites and sulphoxylates; other than sodiumSubheading

Related HS Codes

28.01Fluorine, chlorine, bromine and iodine2801.10Chlorine2801.20Iodine2801.30Fluorine; bromine28.02Sulphur; sublimed or precipitated, colloidal sulphur2802.00Sulphur; sublimed or precipitated, colloidal sulphur28.03Carbon; carbon blacks and other forms of carbon n.e.c.2803.00Carbon; carbon blacks and other forms of carbon n.e.c.

Related Data Resources

ShipCalcWize - Shipping cost calculator →CalcPeek - Unit converters →

Frequently Asked Questions

What is HS Code 28.31?
HS Code 28.31 classifies "Dithionites and sulphoxylates" under Section VI (Products of Chemical or Allied Industries). This heading-level code is used internationally for customs classification, tariff determination, and trade statistics.
What products fall under HS 28.31?
HS Code 28.31 covers: Dithionites and sulphoxylates. This is a broad category that includes more specific subcategories. Browse the child codes below for detailed product classifications.
How do I use HS Code 28.31 for customs?
When classifying goods under HS 28.31, ensure the product matches the specific description. This is a heading-level code. For customs declaration, you may need the more specific 6-digit subheading. Check with your national customs authority for additional digits required.
What are the trade regulations for Products of Chemical or Allied Industries?
Pharmaceutical imports often require regulatory approval (FDA, EMA). Chemical safety data sheets (SDS) are mandatory for most products.
Is HS 28.31 the same in every country?
The first 6 digits of HS codes are standardized worldwide by the World Customs Organization (WCO). However, most countries add additional digits (8-10 total) for their national tariff schedules. Always verify the full code with your destination country's customs authority.
What is the US import duty for HS 28.31?
The average US import duty for products under HS 28.31 is approximately 2.5% (range: 0-6.5%). Most FTAs: 0% Note: actual rates depend on the specific product classification and country of origin. Verify with USITC for official rates.
Can I get a lower tariff rate under a Free Trade Agreement?
Most FTAs: 0%. The US has FTAs with 20 countries including Canada, Mexico (USMCA), South Korea (KORUS), Australia, and others. To qualify for preferential rates, goods must meet rules of origin requirements and have proper documentation (e.g., Certificate of Origin).

Data verified March 2026 · Source: UN Comtrade & USITC

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