Commerce Extends China Manganese Dioxide Tariffs, Locking Supply Chain Cost Into Defense Electronics

The U.S. Department of Commerce and International Trade Commission determined on February 26, 2026, that revoking the antidumping duty order on electrolytic manganese dioxide (EMD) from China would likely cause dumping to resume and material injury to U.S. industry. Commerce is continuing the antidumping duty order indefinitely. The Federal Register notice provides no detail on duty rates, affected volumes, or domestic producer capacity.

The tariff continuation raises the cost basis for any defense program using EMD-dependent components (primarily battery and fuze manufacturers).

If domestic EMD capacity is below current peacetime demand, continuation forces contractors to either accept margin compression on fixed-price contracts or petition for tariff exemptions — both outcomes reduce procurement flexibility and introduce administrative delay into supply chain qualification.

If domestic capacity is adequate, the order simply transfers margin from Chinese suppliers to higher-cost U.S./allied producers, raising the per-unit cost of munitions and reducing the quantity of rounds that can be procured within a fixed budget.

WHY IT MATTERS

Electrolytic manganese dioxide is a critical input for alkaline batteries and certain capacitor types used in defense electronics, missile fuzes, and munitions.

Continuation of the tariff locks Chinese EMD out of the U.S. market, forcing defense contractors and OEMs to source from higher-cost domestic or allied suppliers (primarily Erachem Comilog in the U.S. and Tosoh in Japan) or absorb tariff costs.

This raises component costs for programs with fixed-price contracts and increases supply chain risk if domestic capacity is insufficient to meet surge demand during contingency operations. The decision does not specify whether domestic EMD production meets current or wartime demand, which is the critical gap for defense planning.

WHAT THIS DOESN’T TELL US

The notice does not disclose: (1) the duty rate or duty rates applied; (2) annual import volumes from China pre-tariff or current volumes under the existing order; (3) U.S. domestic EMD production capacity and utilization; (4) which defense programs or contractors are material users of EMD; (5) whet...

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