Product classification
HS code for Trimethyl phosphite: 2920.23
Esters, phosphite esters and their salts, their halogenated, sulphonated, nitrated or nitrosated derivatives, trimethyl phosphite.
Classification of trimethyl phosphite under HS 2920.23
Trimethyl phosphite is classified under HS code 2920.23. This classification is found in Chapter 29 (Organic Chemicals), specifically under Heading 2920, which covers esters of inorganic acids. Trimethyl phosphite is the trimethyl ester of phosphorous acid. The Harmonized System provides specific subheadings for various phosphite esters to assist in the regulation of chemicals that have both industrial and potential military applications. Subheading 2920.23 is the unique identifier for trimethyl phosphite. It is a colorless liquid with a pungent odor, used primarily as a reagent in organic synthesis and as an intermediate in the production of organophosphorus pesticides and flame retardants. Because it is a precursor for the synthesis of certain nerve agents, it is strictly monitored under the Chemical Weapons Convention (CWC). Importers and exporters must use HS code 2920.23 to ensure that the shipment is correctly identified by national authorities responsible for non-proliferation. The classification applies to the chemical in its pure form or as a separate chemically defined compound.
- Covers
- Trimethyl phosphite (TMP) technical grade
- Trimethyl phosphite for agrochemical production
- High-purity TMP for laboratory synthesis
- Trimethyl phosphite used as a polymer stabilizer
- Also under 2920.23
- Lanxess (specialty chemicals)
- Arkema (chemical intermediates)
- Jiangsu Yangnong Chemical Group (agrochemical intermediates)
Codes often confused with 2920.23
Common mistake. Trimethyl phosphite is frequently confused with Triethyl phosphite (2920.24). While they share similar chemical properties, the difference in the alkyl group requires distinct classification. It is also sometimes incorrectly placed in 2931.39, which is a residual category for other organo-phosphorus compounds. However, since TMP is an ester of phosphorous acid, it is specifically directed to Heading 2920 by the HS Explanatory Notes.
Top exporters and importers of HS 292023 (the code used for trimethyl phosphite), 2025
In 2025, the largest exporter of HS 292023 (the code used for trimethyl phosphite) in UN Comtrade data was India, with 85% of world exports; the largest importer in UN Comtrade data was Switzerland, with 41% 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 292023, not only trimethyl phosphite.
Top exporters 2025 · share of world exports
- 1 India $13M 85% of world exports
- 2 China $799K 5.0% of world exports
- 3 United States $728K 4.6% of world exports
World total: $16M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Switzerland $7.4M 41% of world imports
- 2 United States $7.4M 41% of world imports
- 3 United Kingdom $685K 3.8% of world imports
World total: $18M 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 code for trimethyl phosphite
Brazil classifies trimethyl phosphite under NCM 2920.23.00: HS 2920.23 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about trimethyl phosphite
What is the HS code for Trimethyl phosphite?
The HS code for Trimethyl phosphite is 292023 (Esters; phosphite esters and their salts; their halogenated, sulphonated, nitrated or nitrosated derivatives, trimethyl phosphite). The international HS code for Trimethyl phosphite is 2920.23, located within the section for esters of inorganic acids.
How do I classify Trimethyl phosphite for customs?
Trimethyl phosphite is classified under HS code 292023 — Esters; phosphite esters and their salts; their halogenated, sulphonated, nitrated or nitrosated derivatives, trimethyl phosphite. This is a 6-digit subheading level code.
Does Trimethyl phosphite require an export license?
In many jurisdictions, yes. Because it is a CWC Schedule 3 chemical, exports of 2920.23 often require specialized permits and end-user statements.
Which countries are the top exporters of trimethyl phosphite (HS 292023)?
In 2025, the top exporters of HS 292023 (the code used for trimethyl phosphite) in UN Comtrade data were India ($13M, 85% of world exports), China ($799K) and the United States ($728K). World exports came to about $16M, 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 trimethyl phosphite (HS 292023)?
In 2025, the top importers of HS 292023 (the code used for trimethyl phosphite) in UN Comtrade data were Switzerland ($7.4M, 41% of world imports), the United States ($7.4M) and the United Kingdom ($685K). World imports came to about $18M, 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 Trimethyl phosphite the same in all countries?
The base HS code 292023 for Trimethyl phosphite 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 trimethyl phosphite in Brazil?
In Brazil, trimethyl phosphite (HS 292023) is classified under NCM 2920.23.00.