Trade Remedies

Section 232: When "National Security" Enters the Tariff Schedule

Section 301, covered in Part 2 of this series, is triggered by an origin determination — a substantial-transformation test applied to where a product was made. Section 232 starts somewhere else entirely: a finding, made by the Secretary of Commerce and concurred in by the President, that a category of imports threatens to impair U.S. national security. In 2025, President Trump used that authority to reset the steel and aluminum regime on a sweeping basis: prior country arrangements ended, aluminum rose to the steel rate, both rates later doubled, and hundreds of categories of finished goods were brought into the derivative-product net.

---

A Commerce Finding, Not a Trade Practice

Section 232 of the Trade Expansion Act of 1962 (19 U.S.C. §1862) starts with an investigation by the Department of Commerce into whether a category of imports threatens to impair U.S. national security — examining factors like domestic production capacity, demand, employment, and the health of industries Commerce considers essential to national defense. If the Secretary of Commerce finds that imports do threaten to impair national security, that finding goes to the President as a report and recommendation, and the President then has 90 days to decide whether to concur and, if so, what to do about it: tariffs, quotas, or other import restrictions, typically implemented through additions to Chapter 99.

That's a different gate from Section 301's origin test. There's no substantial-transformation analysis at the front end, because the trigger isn't about where a specific product was made — it's about whether Commerce found an entire category of imports to be a security threat. "National security" hasn't stayed narrow, either: what began as a defense-production question has been read to reach economic security and critical infrastructure, and courts reviewing a Section 232 proclamation generally examine whether the President followed the statute's procedure rather than second-guess the underlying finding. The authority has also been used for automobiles and automotive parts and for copper, while other Section 232 investigations have ended without a tariff.

The 2025 Reset: From Patchwork to Broad Coverage

The original March 2018 proclamations imposed 25% on covered steel and 10% on covered aluminum. Over the following years, separate bilateral arrangements — not the free trade agreements themselves — gave countries including Canada, Mexico, Australia, South Korea, the EU, Japan, and the United Kingdom some combination of exemptions, absolute quotas, or tariff-rate quotas. That history explains the old country-by-country patchwork, but it does not describe the regime President Trump put in place in 2025.

Effective March 12, 2025, Proclamations 10895 and 10896 terminated those country arrangements and the associated quotas, ended the general approved exclusions, stopped accepting new product-exclusion requests, and imposed a 25% additional duty on covered steel and aluminum from all countries. Aluminum therefore rose from 10% to 25%. USMCA eligibility did not protect Canadian or Mexican metal, and no country was exempt merely because it had a free trade agreement with the United States. Importer-specific exclusions already granted could run only until their expiration or volume limit.

Effective June 4, 2025, Proclamation 10947 increased the general steel and aluminum rate from 25% to 50%. The United Kingdom temporarily remained at 25% under its separately negotiated Economic Prosperity Deal, but that was a lower Section 232 rate, not an exemption. Russian aluminum — and covered aluminum made anywhere from primary aluminum smelted in Russia or most recently cast there — remained subject to a separate 200% rate. Rates and product lists have continued to change, so an entry-date-specific Chapter 99 check is still essential.

An Origin Question That Reaches Past Final Assembly

Section 301's origin trigger, as Part 2 covered, is the substantial-transformation test — did processing outside China produce an article with a new name, character, or use. Section 232 requires different upstream facts. For steel, CBP reporting reaches to the country where the steel was melted and poured. For aluminum, it reaches to the primary and secondary countries of smelt and the country of most recent cast. Those are metallurgical production steps, not synonyms for where the finished article was assembled.

A finished article can therefore be a product of Canada or Mexico under the ordinary origin rules and still contain steel melted and poured, or aluminum smelted and cast, somewhere else. The importer needs supplier declarations, mill test certificates, bills of material, and cost records that connect the finished SKU to those upstream facts. A free-trade agreement certificate, a commercial invoice stating the final country of origin, or a supplier's assurance that the product is "made in Canada" does not answer the Section 232 questions.

Derivative Products Turned Components into Entry Data

The base tariffs did not stay confined to raw mill products. Proclamation 9980 added selected derivatives in 2020, and the 2025 proclamations created a standing process for adding more. In June 2025, major household appliances and related goods — including refrigerators, washing machines, dishwashers, dryers, freezers, ranges, and food-waste disposals — were added. In August, Commerce added 407 more product categories, reaching wind turbines, mobile cranes, bulldozers, railcars, furniture, compressors, pumps, and hundreds of other finished goods. For many derivatives outside Chapters 73 and 76, the Section 232 duty was assessed on the value of the steel or aluminum content rather than automatically on the full value of the article.

That content-based method created a new filing burden. The importer had to provide the value and quantity of the covered metal content and the required upstream-origin data. CBP instructed that if the value of the aluminum content was unknown, the duty under the ordinary derivative provision had to be reported on the entire entered value; parallel steel guidance used the same whole-value consequence for unknown steel content. A product did not become mostly metal in a physical sense — the larger duty base was the consequence of failing to substantiate the narrower metal-content value.

Unknown Aluminum Can Trigger the 200% Russia Rate

The most severe default was specific to aluminum. Effective June 28, 2025, CBP told importers of covered derivative aluminum products to report "UN" when a primary or secondary country of smelt or the country of most recent cast was unknown. An entry reporting "UN" also had to use heading 9903.85.67 or 9903.85.68, as applicable, and ACE would assess the 200% Section 232 duty used for Russian aluminum. CBP's March 2025 guidance states that the Russia aluminum duty applies to the entire value of the imported good, not merely the value of its aluminum content.

This rule is often summarized too broadly. Unknown aluminum smelt or cast can produce the 200% Russia-rate result; unknown steel melt and pour does not, by itself, turn steel into Russian aluminum or attract that 200% rate. Separately, an importer that cannot establish the value of the steel or aluminum content may have to use the entire entered value as the base for the otherwise applicable Section 232 rate. Keeping those two rules separate matters when calculating exposure.

The Fox40 Key-Ring Problem

In an operational example reported to Kanon, Fox40's experience illustrates how far the 2025 changes reached beyond companies that think of themselves as metal importers. A U.S.-bound shipment was stopped over a minor aluminum key-ring component attached to a largely nonmetal product. The component was commercially incidental, but the entry still required the aluminum content and smelt-and-cast declarations. The shipment could not move until Fox40 obtained the upstream information needed for the customs filing.

The lesson is not that every product containing a stray screw or ring is automatically covered; coverage begins with the article's HTS classification and the derivative lists in effect on the entry date. The lesson is that, once a finished good is on a covered derivative list, a low-value component can control whether the entry is complete and whether the importer can limit the tariff base to the documented metal content. Product engineering, procurement, finance, and customs data all have to connect at the SKU level.

A simple mid-2025 illustration shows the scale of the risk. If a $10,000 covered derivative article contained $100 of documented aluminum, a 50% content-based duty would be $50. If the aluminum-content value could not be substantiated, the 50% rate could instead apply to the $10,000 entered value — $5,000. If the aluminum smelt or cast country was unknown, the separate 200% Russia-aluminum default could produce $20,000 in Section 232 duty on that same entered value. Those figures are illustrative, not Fox40's actual invoice values, but they explain why resolving a small component's data can matter more than the component's purchase price.

Where Section 232 Sits in the Stack

On the Chinese-origin steel example from Part 1 of this series, Section 232 is one of potentially four separately assessed layers on a single entry — the MFN base rate, the Section 232 overlay, a Section 301 overlay, and one or two IEEPA overlays — each governed by its own trigger and exceptions. Getting the Section 301 origin call right, as Part 2 detailed, says nothing about whether the Section 232 metal-content, melt-and-pour, or smelt-and-cast reporting is complete.

Part 4 of this series turns to IEEPA — the newest and fastest-moving Chapter 99 layer, built on a different statutory authority again, and the one most likely to have changed again by the time this series reaches Part 8.

Frequently Asked Questions