Section 338 Canada Aug 19 2026 T-22 Checklist: What Importers Need to Confirm Before the 50 Percent Layer Lands

Section 338 of the Tariff Act of 1930 becomes effective at 12:01 AM Eastern Time on August 19 2026 on a specified list of Canadian-origin goods. That is 22 days from today. For importers with any Canadian lane, this is the pre-effective operational checklist to run this week and next.

Unlike the Section 301 forced-labor rule that had a four-day in-transit grace period, Section 338 as currently proclaimed has no described grace mechanism. Entry-filing timestamp is the sole determinant. That makes pre-effective timing decisions more binary than most 2026 tariff shifts.

Section 338 basics recap

Codified at 19 USC 1338. Authorizes the President to impose additional duties on imports from countries whose acts, policies, or practices discriminate against US commerce. The July 20 2026 proclamations invoked this authority for the first time since the 1940s.

Rate: 50 percent additional ad valorem, stacked on top of MFN and any other applicable duty (with the Section 232 exemption noted above).

USMCA: no shield. This is the critical operational fact.

The three annexes

The July 20 proclamations attached three product annexes.

Annex A: motor vehicles and parts

Includes passenger cars and light trucks assembled in Canada, plus specified auto parts subject to origin sourcing from Canada. Chapter 87 HS lines are the largest cluster. Chapter 84 heat exchangers and engine components used in Canadian-assembled vehicles are also enumerated.

Annex B: alcoholic beverages, wine, and dairy

Chapter 22 wine and spirits, chapter 4 dairy products, and chapter 20 selected food preparations tied to dairy. Wine at chapter 2204 is the highest-value single line. Cheese at chapter 0406 and butter at chapter 0405 are the next tier.

Annex C: cross-sectoral (hockey sticks, cement, and additional items)

Chapter 25 cement and cement clinker. Chapter 95 sporting goods including specific hockey stick subheadings. Chapter 44 selected wood products not already covered by Section 232 wood derivatives. Chapter 48 selected paper products.

Exemptions

Regardless of annex assignment, the following Canadian-origin goods are exempt from Section 338:

• Energy (crude oil, refined petroleum products, natural gas)
• Potash and potash compounds
• Critical minerals as designated
• Fish and seafood
• Goods already subject to Section 232 (aluminum, steel and their derivatives, copper derivatives, passenger vehicles under the 232 regime, medium and heavy-duty vehicles, semiconductors, wood products under the 232 wood proclamation)

The Section 232 exemption is the anti-stacking rule. A steel article from Canada currently paying 50 percent Section 232 does NOT additionally pay Section 338 at 50 percent. Same for aluminum, copper derivatives, and wood.

Worked example: Canadian wine, 100k USD CIF

HTSUS 2204.21 (wine of fresh grapes, 2L containers or less). USMCA-qualifying (Canadian bulk wine or bottled with Canadian grapes).

Pre-August 19 landed duty:

Post-August 19 landed duty:

The 50,000 USD Section 338 layer is the entire net delta. USMCA does nothing here.

The T-22 pre-effective checklist

This week (T-22 to T-18)

1. Extract the three annexes from the July 20 proclamation Federal Register text. Cross-reference against your 90-day Canadian entry history.
2. Flag every HS line that appears on any annex. Compute the 50 percent exposure at your current Canadian import run rate.
3. Model the post-August 19 landed cost for each covered line. This becomes your Q4 sourcing decision input.
4. Identify pull-forward opportunities. Any Canadian shipment that can be arrived, entered, and cleared before 12:01 AM ET August 19 avoids the layer entirely.

Next week (T-15 to T-8)

1. Pre-file entry summaries on merchandise physically present in the port area and ready for entry. ACE accepts advance filing under standard conditions.
2. Coordinate with Canadian suppliers on accelerated production and shipment of anything covered but not already in transit. Air freight economics may work on lower-volume high-value lines (wine, specialty auto parts).
3. Draft Section 338 line-item verification protocols with your customs broker. Broker application of the new layer on annex-covered vs annex-non-covered Canadian lines is the first-week error source, same pattern as the July 24 forced-labor rollout.
4. Verify Section 232 anti-stacking application on all steel, aluminum, copper, wood, and auto lines from Canada. Broker error most likely to appear as double-stacking on these categories in the first weeks.

Cutover week (T-7 to T-0)

1. Freeze non-urgent Canadian import decisions until post-August 19 rate structure is confirmed live. Do not commit to Q4 purchase orders on covered lines without the post-338 landed cost model.
2. Audit entries filed August 18 to August 25 for correct 338 application. PSC or protest is the recovery path if broker misfiled either direction.

What the recent litigation posture means

The Section 338 authority has not been litigated in the modern era. The proclamations are almost certainly headed for CIT review, likely brought by an affected industry group before or shortly after August 19.

An early stay or preliminary injunction would suspend collection but is speculative. Do not model the tariff as reversible for planning purposes; assume it applies as proclaimed until a court order says otherwise.

If a CIT ruling later invalidates the authority, refund standing on Section 338 layers paid between August 19 and the ruling date follows standard protest and PSC procedures. Preserve protest rights on every 338 line by tracking liquidation dates through your broker.

Downstream watch

The Section 338 statute is not country-specific in its text. The July 20 Canada action is likely a template. Trading partners flagged in the same broader trade discussions (EU on digital services taxes, Brazil on Section 301 unrelated action, India on retaliation for prior US actions) are plausible next-round targets under the same authority. Model your non-Canada lanes for a similar 50 percent single-country layer as a contingency scenario through end-of-2026.

Citations

• White House proclamations July 20 2026 (three separate proclamations): https://www.whitehouse.gov/presidential-actions/2026/07/section-338-canada-motor-vehicles/, /alcoholic-beverages-dairy/, /cross-sectoral-annex/
• 19 USC 1338 statutory text: https://www.law.cornell.edu/uscode/text/19/1338
• Section 232 anti-stacking guidance: https://www.cbp.gov/trade/programs-administration/entry-summary/section-232
• CIT rules for challenges to presidential tariff actions: https://www.cit.uscourts.gov/rules