The Section 338 import ban signed on 8 September 2026 changes the question every Canadian brand shipping into the United States has been asking since August. Until last week the answer was arithmetic: add the duty, reprice, move on. Proclamations signed on 8 September put a different answer on the table for part of the list — some goods will not be admitted at all. Two deadlines follow. At 12:01 a.m. eastern time on 15 September 2026, the list of Canadian products carrying the additional 50 per cent Section 338 duty is revised. At 12:01 a.m. eastern time on 29 September 2026, a defined set of Canadian products is excluded from importation into the United States. From today, 11 September 2026, that is four days and eighteen days. If your inventory is on a truck, in a Buffalo cross-dock, or already on its way to an Amazon US fulfillment centre, both dates land on you.
What did the 8 September proclamations actually change?
Two instruments, two very different consequences
Section 338 of the Tariff Act of 1930 gives the President two tools against what the statute treats as discrimination by a foreign country. One is an additional duty. The other is exclusion — barring the goods from entry. Against Canada, only the first had been used until now. The proclamations signed on 8 September 2026 use both, and they are separate documents with separate effective dates. An importer who reads only the headline will conflate them and plan for the wrong date. Section 338 now reaches importers in two distinct ways, and the difference is the difference between a cost and a closed door.
The scope proclamation is the near one. Its text sets the change to take effect at 12:01 a.m. eastern time on 15 September 2026, keeps the additional duty at 50 per cent ad valorem, and restructures the covered list through an annex: Annex I Part A lists products that remain subject to the additional duty, Annex I Part B lists products removed from it, and Annex II carries the matching Harmonized Tariff Schedule modifications on the same date. So the 15 September change cuts both ways. Some importers will find a line they have been paying on has dropped off. Others will find a line they have been clearing at ordinary rates is now dutiable.
| Dimension | 15 September 2026 — scope change | 29 September 2026 — import ban |
|---|---|---|
| Instrument | Additional duty under Section 338 | Exclusion from importation under Section 338 |
| Effective moment | 12:01 a.m. eastern time | 12:01 a.m. eastern time |
| Days from 11 September 2026 | 4 days | 18 days |
| Rate | 50 per cent ad valorem | Not applicable — no entry permitted |
| Interaction with Section 232 | Applies in addition to Section 232 duties | Not applicable |
| CUSMA originating goods | Not exempt | Not exempt |
| Where the covered lines are listed | Annex I Parts A and B, plus Annex II HTSUS changes | Annex to each exclusion proclamation |
| Commercial response | Reprice, or absorb the stacked duty | Re-source, or stock US-side before the date |
What the Section 338 import ban actually prohibits
The exclusion proclamations are the far one, and the more serious. The dairy proclamation states plainly that the covered products of Canada, as set out in its annex, are excluded from importation into the United States effective 12:01 a.m. eastern time on 29 September 2026. Parallel proclamations signed the same day address alcoholic beverages and motor vehicles. This is not a higher rate you can absorb or pass through. An excluded good has no entry to make. There is no duty line to pay, no bond to post, no remission to apply for. For an importer, a Section 338 exclusion removes the transaction rather than repricing it.
One honest caveat, because it matters more than a tidy summary would: the specific tariff lines sit in annexes attached to each proclamation as separate documents. Trade-law firms publishing this week have described the added categories as including certain cheeses, lamps and lighting, furniture, and aluminum and steel structural products, and the removed categories as including items such as salt and cement. Those readings are plausible and consistent with each other, but they are secondary. Before you act on a specific HS code, pull the annex for your own line. Do not price a shipment off a summary — including this one.
Does CUSMA origin protect your goods?
No, and this is where most sellers get caught
It does not. The scope proclamation is explicit that the additional duties apply in addition to duties imposed pursuant to section 232 of the Trade Expansion Act of 1962. Nothing in these measures creates a carve-out for goods that qualify as originating under the Canada–United States–Mexico Agreement. A Canadian-made lamp with a valid CUSMA certification of origin is still a Section 338 good if its tariff line is on the list. Section 338 coverage is decided by tariff line, not by who the importer is or where a good was finished. Importers who built their cross-border model on CUSMA duty-free treatment are the ones most exposed here, because the instinct is to assume origin solves it. It does not.
The stacking point deserves its own sentence. Where a product is covered by both regimes, the Section 338 duty sits on top of the Section 232 duty rather than replacing it. If you are modelling a landed cost for a steel or aluminum article, you are adding two duties, not choosing between them. Our landed cost guide walks through the order of operations; the short version is that the Section 338 line goes in last and it goes in on top.
What this means for India-origin inventory
A separate confusion is worth clearing up, because we hear it weekly. Goods manufactured in India do not become CUSMA goods by passing through a Canadian warehouse. CUSMA applies to North-American-origin goods. Indian-origin inventory routed through an Ontario fulfillment centre and then sold into the United States is imported as Indian-origin goods, on its own tariff treatment, and it needs its own duty analysis. That analysis is unaffected by these Canadian proclamations, but it is not a free pass either — see our India to Canada customs guide for how origin and HS classification interact on that lane.
Which date applies to goods already in transit?
Entry, not departure, is what the clock measures
Both proclamations run off a date and time, not off when a container left a Canadian dock. That is the operational trap. A shipment that crosses on 14 September and is entered for consumption that day is assessed under the current list. The same shipment delayed to 15 September is assessed under the revised one. An importer clearing on 14 September is assessed under one Section 338 list; the same importer clearing a day later is assessed under another. Four days is not much margin if your broker is batching entries or your carrier is running a weekend backlog.
Secondary analyses this week report a transition provision under which goods already imported but not entered for consumption before 29 September remain subject to the 50 per cent duty rather than being turned away. That would be a meaningful relief for anything already on the water or on a truck. Treat it as reported, not settled, until you have read the proclamation text or a CBP message that confirms it applies to your line. If your goods are close to the line, the right move is to ask your broker to confirm the entry date they are targeting, in writing, this week.
What should you do before 15 and 29 September?
A dated action list
- By Friday 12 September: pull the six-digit and ten-digit HS codes for every SKU you ship from Canada into the United States. If you cannot produce that list in an hour, that is the first problem to fix, not the tariff.
- By Saturday 13 September: check each code against the annexes to the 8 September proclamations. Flag three buckets — added to the duty list, removed from it, and named in an exclusion annex.
- By Sunday 14 September: for anything in transit, confirm with your customs broker which entry date they are targeting and whether it falls before or after 12:01 a.m. eastern time on 15 September.
- Monday 15 September: the revised duty list takes effect. Re-run landed cost on every flagged SKU before you let a repricing rule touch your storefront.
- By Friday 19 September: for any SKU in an exclusion annex, decide the alternative now — a non-Canadian source, a US-side stocking position, or withdrawal of the listing. Ten days is enough to move inventory; three is not.
- By Friday 26 September: have US-bound stock of excluded lines physically entered, or accept it will not enter. Confirm your Amazon US inbound plans do not depend on a shipment that cannot clear.
- Monday 29 September: the Section 338 import ban takes effect. Anything still upstream of entry on an excluded line is stranded.
The Canadian side has not stood still
Remember that this is one half of a two-sided dispute. Canada’s counter-tariffs on a list of US-origin goods took effect at 12:01 a.m. on 8 September 2026, and the CBSA guidance on how those surtaxes are applied and declared at the border is separate from anything Washington does. If you import into Canada as well as out of it, you are managing two regimes at once. Our notes on the revised counter-tariff list and the surtax declaration codes cover the Canadian filing mechanics, and duty deferral programs are worth reviewing if goods are transiting rather than landing.
How Transway Xpress Global helps you plan around this
The structural answer to an import ban is not a better spreadsheet. It is inventory positioned on the side of the border where it needs to sell. Transway Xpress Global runs warehouses in Oakville and Etobicoke, Ontario, and in Buffalo, New York, with an office in Pendleton, Indiana, under the trucking parent Transway Transport, which has operated out of Oakville since 2014. That Buffalo position is the practical hedge here: stock that is already inside the United States is not waiting on an entry that may not be allowed. For most sellers, Section 338 exposure is an inventory-position problem before it is an import-paperwork problem.
For brands that need to keep selling on both sides, the work is a mix of cross-border shipping, customs documentation, and US fulfillment for Canadian brands so that a Canadian-origin SKU facing an exclusion can be served from US stock while you re-source. We also handle D2C and B2B fulfillment, Amazon FBA prep, warehousing, order and inventory management, returns and custom packaging — which matters in a week like this, because the constraint is rarely the tariff alone. It is usually the tariff plus an FBA Q4 cut-off arriving at the same time.
Accuracy on paperwork carries more weight when the penalty for a misclassification is exclusion rather than a duty bill. If your commercial invoice describes goods loosely, a border officer’s reading of the annex becomes the operative one, not yours.
Summary
Two dates, two different kinds of problem. On 15 September 2026 at 12:01 a.m. eastern time, the Section 338 duty list changes and some importers will owe 50 per cent on lines they did not owe it on before, stacked on top of any Section 232 duty. On 29 September 2026 at 12:01 a.m. eastern time, a Section 338 import ban takes effect on a defined set of Canadian products, and for those lines the cost question disappears because entry does. CUSMA origin does not exempt covered goods from either. Section 338 leaves the importer of record carrying both the duty risk and the admissibility risk. The scope of each list lives in the annexes, so verify your own codes before you reprice or re-source. For wider context on how the duty regime developed through 2026, see our US–Canada tariffs overview.
Frequently Asked Questions
What is the Section 338 import ban?
It is an exclusion from importation, not a tariff. Proclamations signed on 8 September 2026 under Section 338 of the Tariff Act of 1930 bar a defined set of Canadian products from being imported into the United States, effective 12:01 a.m. eastern time on 29 September 2026. Separate proclamations cover dairy, alcoholic beverages and motor vehicles, and each carries its own annex listing the affected tariff lines. Unlike an additional duty, a good excluded under Section 338 cannot be imported at any price.
When does the 50 per cent Section 338 duty list change?
At 12:01 a.m. eastern time on 15 September 2026 — four days from 11 September. A proclamation signed on 8 September 2026 modifies the scope of Canadian products subject to the additional 50 per cent ad valorem duty. Its Annex I Part A lists products that remain covered, Annex I Part B lists products removed, and Annex II makes the matching Harmonized Tariff Schedule changes. Both additions and removals take effect at the same moment, so importers should check for both.
Does CUSMA origin exempt my goods from Section 338 duties?
No. Nothing in these measures exempts goods that originate under CUSMA, and the scope proclamation states that the additional duties apply in addition to duties imposed under Section 232 of the Trade Expansion Act of 1962. A Canadian-made product with valid CUSMA certification is still covered if its tariff line appears in the annex. Separately, India-origin inventory shipped through a Canadian warehouse is not CUSMA-originating at all and is imported on its own tariff treatment.
What happens to Canadian goods already in transit on 29 September?
The operative test is when goods are entered for consumption, not when they were shipped. Secondary trade-law analyses published this week report a transition provision keeping goods imported but not yet entered before 29 September subject to the 50 per cent duty rather than exclusion. That has not been confirmed here against the proclamation text or a CBP message, so confirm with your customs broker which entry date applies to your shipment before assuming relief.
How do I find out whether my product is on the list?
Start from your own HS classification rather than a product description. Pull the ten-digit codes for every SKU you ship from Canada into the United States, then check each against the annexes attached to the 8 September 2026 proclamations on the White House presidential actions page. Categories reported in trade-press summaries are a useful starting point but are not authoritative for your line. If classification is uncertain, resolve it with a customs broker before 15 September.
If you need help repositioning inventory ahead of either date — US-side stocking, FBA prep, or a cross-border plan that does not depend on a shipment clearing — book a consultation with Transway Xpress Global and we will work through your SKU list with you.
Primary sources: Proclamation excluding certain Canadian dairy products from importation (White House, 8 September 2026); Proclamation modifying the scope of products of Canada subject to additional duties (White House, 8 September 2026); CBSA guidance on Canadian tariffs on certain US goods.
