U.S. imports of Expandable Polystyrene (EPS) in Primary Forms (HS 390311) totaled $28.7M in August 2026, imported from 19 countries.
Importers of Expandable Polystyrene (EPS) in Primary Forms paid $440K in duties in August 2026, an average duty rate of 1.53% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: August 2026 dataExpandable polystyrene — universally known as EPS — is polystyrene beads impregnated with a blowing agent (typically pentane) that expand when heated to produce lightweight foam for packaging, insulation board, and protective molding. The entire heading resolves to a single 10-digit line (3903110000), so classification disputes more often involve distinguishing EPS from non-expandable polystyrene (heading 390319) based on the presence and content of the blowing agent. Mexico and Canada are the leading US suppliers, with South Korea also a notable source. EPS imports from Mexico may qualify for USMCA preferential treatment when rules-of-origin requirements are satisfied.
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694 import shipments a month
The defining characteristic is the presence of an incorporated blowing agent — typically pentane — within the bead structure. CBP may request a certificate of analysis or technical data sheet confirming blowing-agent content and bead morphology. Material that lacks an incorporated blowing agent is classified under heading 390319 as non-expandable polystyrene.
EPS beads contain residual pentane, a flammable hydrocarbon, which triggers hazardous-materials handling requirements under DOT regulations for certain shipment modes. Importers should confirm that shipping documentation (including Safety Data Sheets) correctly identifies the flammability classification and that carriers are equipped to handle the material in compliance with 49 CFR hazmat rules.
Subheading 2 of 5 in heading 3903
Subheading 390311 · $28.7M of $100.5M
Trade Directory
List your company under HS 390311 — Expandable Polystyrene (EPS) in Primary Forms, so the companies trading it can find you. Be the first supplier listed.
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 |
|---|---|---|---|---|---|
| 3903110000 | Polystyrene, Expandable | $28.7M | 1.53% | 11.82% | $440K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 3903110000 | Polystyrene, Expandable | $7.8M |
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
Canada and Mexico together supply 88% of it. Bahamas pays 19.0% duty; Mexico 0.0%.
customs district
destination
entry
rate provision · imports
88.2% enters free of duty; duty collected equals 1.53% of imports for consumption.
ImportsExports
Imports
$28.7MYoY · free account
Exports
$7.8MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $353.3M of Expandable Polystyrene (EPS) in Primary Forms and exported $121.3M.
Through August 2026. Source: U.S. Census Bureau.