US Customs and Border Protection began rejecting covered Canadian imports at 12:01 a.m. Eastern Time on 29 September, locking in restrictions issued under Presidential Proclamations 11061, 11062 and 11063.

The measures, signed on 8 September, target specified Canadian alcoholic beverages, dairy-related products and motor-vehicle-sector goods. CBP said any entry containing covered products will be refused, and that affected cargo cannot enter a Foreign Trade Zone (FTZ), sit in a bonded warehouse, or move under in-bond transportation.

For US importers and customs brokers, the change converts a previously announced tariff package into hardline enforcement at the ACE Cargo Release and FTZ systems. Non-compliant filings now trigger automatic rejection messages.

What products are blocked?

The three proclamations carve out three distinct product groups: certain alcoholic beverages, dairy-linked goods, and motor-vehicle-sector items. CBP has not published a consolidated HS-code list beyond the scope of each proclamation, leaving classification decisions to importers and their brokers.

Any entry that mixes covered goods with exempt merchandise faces the same rejection. CBP's guidance is binary: covered products are not admitted, regardless of the value share within the entry.

How are pre-deadline stocks treated?

Goods that entered an FTZ or bonded warehouse before 29 September can still be withdrawn for consumption. Withdrawals, however, will generally carry the 50% ad valorem duty established under earlier presidential proclamations.

CBP also clarified the alcohol scope. Where an exclusion applies only to packaged products, it covers bottles, cans, boxes, kegs and similar containers intended for direct consumption. Alcoholic beverages falling outside that scope are not covered by the import exclusion, but they remain subject to the same 50% duty.

Distributors holding inventory in US FTZs must now weigh the duty cost against disposal or re-export, while the bonded-warehouse buffer that had previously softened the impact disappears for any post-29 September arrivals.

What changed in ACE?

CBP has updated its Automated Commercial Environment to enforce the rules. Non-compliant submissions now produce rejection messages through both Cargo Release and Foreign Trade Zone processing channels.

The systems update shifts responsibility to the filer. Brokers and self-filing importers must reconcile HS codes against all three proclamations before transmitting entries, or risk rejections that cascade into detention and storage charges at inland ports.

What are the commercial consequences?

For Canadian exporters of alcoholic beverages, dairy and motor-vehicle components, US-bound volumes already weighed down by the 50% rate now face outright refusal. Shippers with continuous service contracts will see booked cargo rolled or returned at origin.

US importers must clear bonded warehouses ahead of consumption withdrawals or accept the 50% surcharge as a cost of sale. The effective closure of FTZ warehousing as a duty buffer narrows the sourcing options for buyers that had been using Canadian product to fill specific retail slots.

CBP signalled that the framework builds on proclamations already on the books, leaving room for further product additions or removals as bilateral talks evolve. Canadian exporters and US importers should plan for continued volatility in cross-border lane classification through the fourth quarter.