U.S. imports of Phosphinates (Hypophosphites) & Phosphonates (HS 283510) totaled $4.0M in August 2026, imported from 11 countries.
Importers of Phosphinates (Hypophosphites) & Phosphonates paid $1.5M in duties in August 2026, an average duty rate of 37.81% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule. Phosphinates (Hypophosphites) & Phosphonates imports of $4.0M in August 2026 ran 118% above the year-to-date monthly average of $1.8M.
Last updated: August 2026 dataPhosphinates and phosphonates are specialty phosphorus compounds used as flame retardants, scale inhibitors in water treatment, and intermediates in pharmaceutical and agrochemical synthesis. China is the dominant US import source under this heading, and imports from China are subject to Section 301 tariffs, a significant cost consideration for formulators relying on Chinese supply. The heading resolves to a single tariff line, 2835100000, covering both phosphinates (hypophosphites) and phosphonates regardless of the specific metal cation or organic substituent.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
26 import shipments a month
Inorganic phosphonates and phosphinates (hypophosphites) are classified here under 2835100000. Organic phosphonate compounds, however, may be classified in Chapter 29 as organic phosphorus compounds depending on their chemical structure. The distinction between inorganic salts and organic derivatives is the key classification boundary, and a licensed customs broker should be consulted for complex molecules.
Because China is the leading supplier and Chinese-origin phosphonates are subject to Section 301 tariffs, many US importers have explored alternative sources such as Switzerland, Japan, and India. However, supply concentration and technical specifications often limit substitution options, making tariff engineering (e.g., first-sale valuation or bonded warehouse strategies) a common mitigation approach.
Subheading 4 of 8 in heading 2835
Subheading 283510 · $4.0M of $38.7M
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ImportsExports
Imports
$4.0MYoY · free account
Exports
$322KYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $22.0M of Phosphinates (Hypophosphites) & Phosphonates and exported $2.1M.
Through August 2026. Source: U.S. Census Bureau.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 2835100000 | Phosphinates (Hypophosphites) & Phosphonates | $4.0M | 37.81% | 100.00% | $1.5M |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 2835100000 | Phosphinates (Hypophosphites) & Phosphonates | $322K |
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.
Imports · August 2026
origin
China and Switzerland together supply 98% of it. China pays 39.2% duty; Denmark 10.0%.
customs district
destination
entry
rate provision · imports
duty collected equals 37.81% of imports for consumption.