Product classification
HS code for Chemical initiators: 3815.90
Reaction initiators, reaction accelerators and catalytic preparations, unsupported, n.e.c. or included.
Classification of chemical initiators under HS 3815.90
Chemical initiators, reaction accelerators, and catalytic preparations are classified under HS code 3815.90 when they are not supported and not elsewhere specified. This classification follows GIR 1, which prioritizes the terms of the headings and any relative section or chapter notes. Heading 3815 covers products that initiate or accelerate chemical reactions. Subheading 3815.90 serves as a residual category for those preparations that do not consist of precious metals or their compounds on a support (which would fall under 3815.12) or other supported catalysts (3815.11 or 3815.19). These initiators are often complex mixtures or specific chemical preparations used in polymerization processes, such as the production of plastics and synthetic resins. It is important to note that if an initiator consists of a single chemically defined compound, it is generally excluded from Chapter 38 and classified in Chapter 28 or 29. However, when these substances are presented as preparations or mixtures designed for a specific catalytic function, they are correctly placed in 3815.90. The classification depends on the physical form, the presence of a support material, and the specific chemical composition of the mixture.
- Covers
- Polymerization initiators (mixtures)
- Organic peroxide preparations used as initiators
- Non-supported reaction accelerators
- Mixed catalysts not containing precious metals
- Redox initiators for industrial chemistry
- Also under 3815.90
- BASF catalysts
- Evonik catalysts
- Johnson Matthey catalysts
- Arkema initiators
- Clariant catalysts
Codes often confused with 3815.90
Common mistake. Chemical initiators are frequently misclassified under HS codes 3815.11 through 3815.19. These codes are specifically for supported catalysts, which are active substances deposited on a carrier like silica, alumina, or activated carbon. If the initiator is unsupported, it must go to 3815.90. Another common error is classifying pure organic peroxides under 2909.60. While pure chemicals belong in Chapter 29, preparations containing these chemicals for specific industrial use as initiators are moved to 3815.90. Finally, finished rubber accelerators are classified under 3812.10, not 3815.90.
Top exporters and importers of HS 381590 (the code used for chemical initiators), 2025
In 2025, the largest exporter of HS 381590 (the code used for chemical initiators) in UN Comtrade data was the United States, with 26% of world exports; the largest importer in UN Comtrade data was Thailand, with 8.6% 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 381590, not only chemical initiators.
Top exporters 2025 · share of world exports
- 1 United States $1.2B 26% of world exports
- 2 Germany $1.0B 23% of world exports
- 3 Japan $431M 9.5% of world exports
World total: $4.6B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Thailand $417M 8.6% of world imports
- 2 South Korea $337M 6.9% of world imports
- 3 China $335M 6.9% of world imports
World total: $4.9B 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 chemical initiators
Brazil splits HS 3815.90 into 5 NCM codes. Pick the one that matches your product:
- 3815.90.10Petroleum cracking catalysts
- 3815.90.91Isoprenylaluminium (IPRA) catalysts
- 3815.90.92Zinc oxide catalysts
- 3815.90.93Rare-earth oxide catalysts
- 3815.90.99Other reaction initiators and catalysts
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about chemical initiators
What is the HS code for Chemical initiators?
The HS code for Chemical initiators is 381590 (Reaction initiators, reaction accelerators and catalytic preparations, unsupported, n.e.c. or included). The HS code for chemical initiators and reaction accelerators (unsupported and n.e.c.) is 3815.90.
How do I classify Chemical initiators for customs?
Chemical initiators is classified under HS code 381590 — Reaction initiators, reaction accelerators and catalytic preparations, unsupported, n.e.c. or included. This is a 6-digit subheading level code.
When should an initiator be classified in Chapter 29 instead of 3815?
An initiator should be classified in Chapter 29 if it is a single chemically defined compound. HS code 3815.90 is reserved for preparations, mixtures, and compounds that do not meet the purity or definition standards of Chapter 29.
Which countries are the top exporters of chemical initiators (HS 381590)?
In 2025, the top exporters of HS 381590 (the code used for chemical initiators) in UN Comtrade data were the United States ($1.2B, 26% of world exports), Germany ($1.0B) and Japan ($431M). World exports came to about $4.6B, 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 chemical initiators (HS 381590)?
In 2025, the top importers of HS 381590 (the code used for chemical initiators) in UN Comtrade data were Thailand ($417M, 8.6% of world imports), South Korea ($337M) and China ($335M). World imports came to about $4.9B, 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 Chemical initiators the same in all countries?
The base HS code 381590 for Chemical initiators 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 chemical initiators in Brazil?
Brazil splits HS 381590 into 5 NCM codes, so the right one for chemical initiators depends on the product's details: 3815.90.10 (Petroleum cracking catalysts), 3815.90.91 (Isoprenylaluminium (IPRA) catalysts), 3815.90.92 (Zinc oxide catalysts), 3815.90.93 (Rare-earth oxide catalysts), 3815.90.99 (Other reaction initiators and catalysts).