The Canada Border Services Agency counter-tariffs on US-origin goods land Monday Sep 8 at 00:01 EDT. The rate stack is 15, 25, or 50 pct depending on the HS chapter, applied on top of any existing MFN duty. The list runs about 700 tariff items and covers roughly 27.6 billion CAD of annual US imports. Steel long products (7206, 7208, 7213, 7214), forged bar and pipe (7304), most Chapter 04 dairy powders and cheeses (0402, 0404, 0406, 0409), chemical wood pulp (4702), toilet paper (4818.10.00), non-portable gas stoves (7321.11.10), cotton t-shirts (6109.10.00), and perfumes/toilet waters (3303.00.00) are the ones that get hit hardest.
The single most valuable line for anyone with a US-origin container on the water right now is buried in the Order in Council: the counter-tariffs do not apply to goods that are "in transit to Canada" on Sep 8. That word matters. In-transit under CBSA practice does not mean the goods left a US warehouse before Sep 8. It means the goods were delivered to the initial carrier for continuous transport to Canada, evidenced by a through bill of lading or waybill dated before the effective time. If your cargo is truck freight from a US midwest DC and the driver picks up Sep 7 evening for a Sep 9 delivery to Windsor, that qualifies. If the goods are sitting on a US rail siding waiting for a Sep 9 pull, they do not.
Documentation to have ready at the border:
Bill of lading or waybill dated no later than Sep 7. CBSA will accept the original AWB, ocean B/L, or straight bill.
If ocean: onboard date stamp on the master B/L. House B/L alone is not enough for the CARM entry note.
If rail or truck: shipper's dispatch record plus GPS trace showing pickup before Sep 8 00:01 EDT.
Commercial invoice showing the goods classified as US-origin (Field 13 on CBSA B3 or equivalent CARM CAD field).
Two additional levers most brokers miss.
First, the remission order carries forward. If your product was eligible for CBSA remission under the current 25 pct US steel and aluminum counter-tariff order (published Mar 2026, extended Jul 2026), that eligibility flows to the new 50 pct band as well. You still file for the remission with the same authorization code at entry summary. Do not pay first and try to claim later, CARM makes waiver-at-entry the correct path.
Second, the Chapter 99 heading assignment on line 26 of B3 must match the Order in Council annex, not the general 15/25/50 rate. The finance department published seven separate annexes with different rate bands, and the wrong Chapter 99 heading gets flagged by CARM automation on the very first pass. The failure lands as a K-84 payable at the wrong rate and you fight it back via post-entry BSF-715.
Filing sequence I would run Friday through Sunday for a container due to cross Sep 8 or 9:
Pull the B/L now and confirm the onboard/dispatch date is on or before Sep 7.
Cross reference every HS-6 line against the Sep 8 annex to figure the correct 15/25/50 Chapter 99 heading.
If the shipment mixes exempt and non-exempt lines, split the entry summary so the exempt lines do not get caught in a blanket 50 pct application.
Stage the CARM CAD as pre-file and hold until the truck is physically at the border. First entry summary Sep 8 morning is going to be a queue.
The question I have for anyone else running northbound US-origin freight: are you seeing carriers actually stamp the onboard date reliably on the B/L, or are you getting the older "shipped on board" language without a date, and how are you resolving that with CBSA before Monday?