US Tariff on Chemicals from South Korea

Importing chemicals from South Korea into the US in 2026 means navigating multiple tariff layers. The current total effective rate runs approximately 10% on most chemicals imports under HTS chapters 28-29, 32-38. The pre-SCOTUS IEEPA reciprocal rate on South Korea was 25% — meaning importers who paid duties between April 2025 and February 2026 are owed an IEEPA refund of roughly 15% of declared value, plus ~5% statutory interest.

The current rate stack on chemicals from South Korea breaks down as: the 10% Section 122 reciprocal tariff (effective February 24, 2026, set to expire July 24, 2026 unless extended), plus the MFN duty rate that depends on the specific HTS code, plus any product-specific surcharges.

For most importers, the 10% total represents a meaningful change from the pre-SCOTUS regime, when the IEEPA reciprocal layer pushed South Korea chemicals imports to 25% effective. SCOTUS struck down the IEEPA reciprocal layer on February 20, 2026 in Learning Resources v. Trump, opening a refund pool of approximately $166 billion for affected importers.

KORUS preferential treatment can zero the MFN base on qualifying goods — but Section 122 still applies. If your goods qualify, the refund window is still open through Phase 1 of the CAPE portal (CBP's refund track) for entries that are unliquidated or within 80 days of liquidation.

Bottom line for chemicals importers from South Korea: confirm your HTS classification, account for the Section 122 layer (and Section 232/301 if applicable), and — if you paid IEEPA duties in 2025 — check your refund eligibility before the Phase 1 windows close on a rolling basis through Q3 2026.