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HSChapter 38
U.S. exports of reaction initiators, reaction accelerators & other catalytic preparations (HS 381590) totaled $80.9M in July 2026.
Importers of Reaction Initiators, Reaction Accelerators & Other Catalytic Preparations paid $3.4M in duties in July 2026 — an effective duty rate of 18% on $19.2M in dutiable value, based on actual customs collections rather than the published tariff schedule. Reaction Initiators, Reaction Accelerators & Other Catalytic Preparations imports of $25.0M in July 2026 ran 19% above the year-to-date monthly average of $20.9M.
Last updated: July 2026 dataReaction initiators, accelerators, and catalytic preparations not classified as supported catalysts encompass a broad range of industrial chemicals — including peroxide-based polymerization initiators, organometallic accelerators, and inorganic catalytic formulations — used across polymer production, coatings, and specialty chemical manufacturing. The US schedule separates inorganic-substance initiators by metal type (bismuth-based at 3815901000, mercury-based at 3815902000, and other inorganic at 3815903000) from the broader organic and mixed residual line (3815905000). Germany leads US import supply, with Japan and Canada also significant sources. Mercury-containing initiators (3815902000) face stringent import restrictions under the Mercury Export Ban Act and EPA regulations, making pre-import compliance review essential for that specific line.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
601 shipments/mo
The Mercury Export Ban Act and EPA regulations impose strict controls on mercury and mercury-added products. Importers should verify whether the mercury content triggers EPA notification or permit requirements, confirm that the import is not prohibited under applicable restrictions, and ensure the commercial invoice clearly identifies the mercury compound and its concentration. Consultation with a licensed customs broker and environmental counsel is strongly recommended.
Both fall under heading 381590, but the distinction matters for understanding the product's commercial function: initiators (such as organic peroxides) start a chemical reaction by generating reactive species, while accelerators (such as certain metal salts or amine compounds) increase the rate of an already-initiated reaction. For HTS purposes, both types are captured within the same heading, with the inorganic/organic distinction and specific metal identity driving the 10-digit line selection.
Subheading 3 of 4 in heading 3815
Subheading 381590 · $25.0M of $199.8M
ImportsExports
Imports
$25.0MYoY · Pro
Exports
$80.9MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
Exports · July 2026
destination
customs district
origin
entry
rate provision · imports
23.3% enters free of duty; the effective duty rate is 13.60%.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 3815905000 | Reactton Initiators & Reaction Accelerators, NESOI | $13.0M | 11.42% | 71.29% | $1.5M |
| 3815903000 | Reaction Initiator, Of Inorganic Substances,NESOI | $10.4M | 14.00% | 95.72% | $1.5M |
| 3815901000 | Reaction Initiator, Of Inorganic Subst,Bismuth Etc | $326K | 8.31% | 50.38% | $27K |
| 3815902000 | Reaction Initiator, Of Inorganic Subs, Mercury Etc | $0 | -- | -- | -- |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 3815900000 | Reaction Initiators & Accelerators, Etc, NESOI | $90.7M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
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