Product classification
HS code for CMC: 3912.31
Cellulose ethers, carboxymethylcellulose and its salts, in primary forms.
Classification of CMC under HS 3912.31
Carboxymethylcellulose (CMC) and its salts are classified under HS code 3912.31. This classification falls under Chapter 39 (Plastics and articles thereof), specifically within the heading for cellulose and its chemical derivatives. CMC is a cellulose ether produced by reacting cellulose with chloroacetic acid. The classification 3912.31 is specific to the carboxymethyl group and its salts (such as Sodium Carboxymethyl Cellulose). The product is typically traded in primary forms, such as white or off-white powders or granules, which are soluble in water and used as thickeners, binders, and stabilizers in food, pharmaceuticals, and industrial applications. The classification is driven by the chemical structure of the polymer, where the hydroxyl groups of the cellulose backbone are partially substituted with carboxymethyl groups.
- Covers
- Sodium Carboxymethyl Cellulose (Na-CMC)
- Purified CMC powder
- Technical grade CMC for oil drilling
- Food-grade cellulose gum
- CMC salts in primary forms
- Also under 3912.31
- Ashland Aqualon CMC
- Dow Walocel CMC
- CP Kelco Finnfix CMC
- DuPont Tylose CMC
- AkzoNobel Bermocoll CMC
Codes often confused with 3912.31
Common mistake. CMC is often misclassified under 3912.39, which is the residual category for "other" cellulose ethers like methylcellulose or hydroxypropyl cellulose. Another common mistake is 3913.90 (other natural polymers), but since CMC is a chemically modified derivative of cellulose, it is strictly governed by the 3912 heading. In some cases, if the CMC is prepared as a finished glue or adhesive, it might be misclassified under 3506, but in its primary powder form, 3912.31 is correct.
Top exporters and importers of HS 391231 (the code used for CMC), 2025
In 2025, the largest exporter of HS 391231 (the code used for CMC) in UN Comtrade data was China, with 27% of world exports; the largest importer in UN Comtrade data was the United States, with 12% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 391231, not only CMC.
Top exporters 2025 · share of world exports
- 1 China $269M 27% of world exports
- 2 Finland $134M 14% of world exports
- 3 Netherlands $85M 8.6% of world exports
World total: $988M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $130M 12% of world imports
- 2 India $78M 7.3% of world imports
- 3 China $62M 5.8% of world imports
World total: $1.1B Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM codes for CMC
Brazil splits HS 3912.31 into 4 NCM codes. Pick the one that matches your product:
- 3912.31.11Carboxymethylcellulose, CMC content 75% or more
- 3912.31.19Carboxymethylcellulose, CMC content below 75%
- 3912.31.21Carboxymethylcellulose salts, content 75% or more
- 3912.31.29Carboxymethylcellulose salts, content below 75%
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about CMC
What is the HS code for CMC?
The HS code for CMC is 391231 (Cellulose ethers; carboxymethylcellulose and its salts, in primary forms). The HS code for Carboxymethylcellulose (CMC) and its salts is 3912.31.
How do I classify CMC for customs?
CMC is classified under HS code 391231 — Cellulose ethers; carboxymethylcellulose and its salts, in primary forms. This is a 6-digit subheading level code.
Is food-grade CMC classified differently than industrial-grade?
No, both food-grade and industrial-grade CMC are classified under 3912.31, provided they are in primary forms and not mixed with other ingredients that change the product's essential character.
Which countries are the top exporters of CMC (HS 391231)?
In 2025, the top exporters of HS 391231 (the code used for CMC) in UN Comtrade data were China ($269M, 27% of world exports), Finland ($134M) and the Netherlands ($85M). World exports came to about $988M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of CMC (HS 391231)?
In 2025, the top importers of HS 391231 (the code used for CMC) in UN Comtrade data were the United States ($130M, 12% of world imports), India ($78M) and China ($62M). World imports came to about $1.1B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for CMC the same in all countries?
The base HS code 391231 for CMC is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for CMC in Brazil?
Brazil splits HS 391231 into 4 NCM codes, so the right one for CMC depends on the product's details: 3912.31.11 (Carboxymethylcellulose, CMC content 75% or more), 3912.31.19 (Carboxymethylcellulose, CMC content below 75%), 3912.31.21 (Carboxymethylcellulose salts, content 75% or more), 3912.31.29 (Carboxymethylcellulose salts, content below 75%).