Section 232 Steel and Aluminum: What CBP's Latest Guidance Actually Changes
Section 232 tariffs on steel and aluminum have been moving fast. The rate went from 25% to 50% on June 4, 2025. The list of covered derivatives has expanded significantly, with more than 400 product codes added in August 2025 alone. Country exemptions are gone. The exclusion request process has been terminated. And CBP has been actively clarifying how the rules apply to derivative articles, which is where most of the compliance complexity lives.
The CBP Base Metals Center of Excellence and Expertise recently issued updated guidance addressing three specific areas that had been generating real confusion in the trade community: how to apportion shared costs between subject and non-subject content, how to handle derivative articles where the primary product is not made of steel or aluminum, and how iron articles are treated under Section 232. This post covers all three, plus the broader context importers need to understand where the rules currently stand.
Where things stand as of 2026
The baseline: since March 12, 2025, all steel and aluminum imports face a 25% tariff with no country exemptions and no exclusions. As of June 4, 2025, that rate increased to 50% for most trading partners. The UK is a partial exception, remaining at 25% under the terms of the U.S.-UK Economic Prosperity Deal, though the Secretary of Commerce can adjust that rate based on compliance with the deal's terms.
Section 232 tariffs and IEEPA tariffs interact in a way that matters for importers of derivative articles. For derivative products, Section 232 applies only to the steel or aluminum content value. The non-steel, non-aluminum content of the same article is subject to applicable IEEPA reciprocal tariff rates based on country of origin. These are assessed on two separate lines of the Entry Summary. Getting that split right is the core compliance challenge for derivative importers, and it is exactly what the new CBP guidance addresses.
One more piece of context: goods subject to Section 232 are excluded from IEEPA reciprocal tariffs on their subject content. That exclusion is under HTS 9903.01.33. But it only applies if Section 232 duties are actually owed and payable. If an article has no steel or aluminum content subject to Section 232 duties, the exclusion cannot be claimed, and the full IEEPA reciprocal duty may apply.
Apportioning shared costs between subject and non-subject content
This has been the most contested practical question under the derivative rules. When a product contains both steel or aluminum content and non-subject content, certain costs sit in both camps: labor, overhead, profit, packaging. These are costs of production that relate to the article as a whole, not exclusively to the metal or exclusively to the rest of the product.
CBP's guidance confirms that an acceptable method for handling these shared costs is to apportion them to both entry lines based on a value ratio. The ratio is calculated from the relative value of the steel or aluminum content versus the non-subject content. Costs get split proportionally. This gives importers a workable methodology that does not require cost accounting precision down to the unit, but it does require that the underlying content values be documented and supportable.
The risk of not having that documentation is not abstract. CBP has stated directly that if an importer cannot document the steel or aluminum content value in a derivative article, the entire entered value is subject to the 50% Section 232 duty. That is not a penalty on top of the normal rate. That is the normal rate applied to the full value because no separation of content could be demonstrated. For importers of derivative articles with a mix of steel and non-steel components, getting the documentation in order before an entry is audited is the right order of operations.
Derivative articles where the steel or aluminum is the container, not the product
This is one of the more counterintuitive aspects of the Section 232 derivatives rules, and the CBP guidance has now stated it explicitly. If an article that is obviously not made of steel or aluminum, such as perfume, lotion, or a consumer product, appears on the Section 232 derivatives HTS list, the duty is not on the product. It is on the container, if that container is made of aluminum or steel.
The practical example from the guidance is malt beer in an aluminum can, classified under HTS 2203.00.0060 and 2203.00.0090. The beer itself is not subject to Section 232. The aluminum can is. The Section 232 duty applies to the importer's cost of the can. Not the full FOB value of the shipment. Not the value of the contents. Just the cost of the metal container.
This matters for any importer bringing in food, beverages, personal care products, or similar goods packaged in steel or aluminum containers. The tariff exposure is on the packaging, and it should be calculated based on what the importer paid for that packaging specifically. Importers who have been applying Section 232 to the full entered value of such products need to revisit how they have been filing.
Iron articles under Section 232: a shifting timeline
Iron has had a more complicated history under Section 232 than steel or aluminum, and the CBP guidance has clarified both the current rule and the timeline of how it got there. The current approach is that iron content value is determined using the same method as steel and aluminum. That is the new standard going forward. But the timeline of when iron articles were and were not subject to Section 232 is worth understanding for anyone reviewing historical entries or managing ongoing compliance.
Iron articles classified in Chapter 72 have been subject to Section 232 duty since March 2018, assessed on the full entered value. That has not changed. For iron articles outside Chapter 72, the picture is more complicated. From March 2018 through March 11, 2025, iron articles paid Section 232 duty. From March 12, 2025 through June 3, 2025, derivative iron articles and iron parts classified outside of Chapter 73 did not pay Section 232 duty, with specific exceptions for Chapter 72, HTS 8708.10.30, and HTS 8708.29.21. From June 4, 2025 onward, iron articles and iron parts classified in Chapter 73 and derivative articles classified elsewhere do not pay Section 232 duty, again with the same exceptions for Chapter 72 and the two specific HTS codes. The term 'parts' in that context refers to subject steel, aluminum, or copper articles that contain non-subject iron parts.
For importers who have iron parts or iron-containing derivative articles in their import program, this timeline determines what was owed when, and it is relevant both for prospective compliance and for reviewing whether prior entries were calculated correctly.
What to do with this
The documentation piece is not negotiable. If you import derivative articles that contain steel, aluminum, or iron, you need to be able to show how you valued the subject content separately from the non-subject content, and how you apportioned shared costs. A value ratio method is acceptable. Guessing is not. CBP has confirmed that an undocumented derivative article can have its entire entered value subjected to the 50% rate, and the current enforcement environment is not one where importers should be testing that outcome.
The container rule is worth reviewing against your product catalog. If you import goods packaged in steel or aluminum that appear on the derivatives list, check whether you are calculating the Section 232 duty on the cost of the container or on something else. The guidance is now explicit that it is the container cost that is the basis.
For iron articles, run your current HTS classifications against the timeline above to confirm you are applying the right rule for the right period. The March 12, 2025 and June 4, 2025 effective dates both changed what was owed, and misclassification across those dates could create either underpayment or overpayment situations.
How ShipTech can help
Our customs brokerage team works through Section 232 classification and valuation questions regularly. If you are unsure whether your derivative articles are being calculated correctly, or if you want to review how the iron timeline applies to your specific HTS codes, reach out to your ShipTech account manager. Getting the content valuation right before an audit is considerably less expensive than correcting it after one.