SMM reported September 12 that the US-Canada tariff exchange escalated again after Ottawa imposed retaliatory tariffs on approximately 20 billion dollars of US goods.
Washington responded with a 50 percent tariff on about 100 additional Canadian product categories effective September 15.
Import prohibitions on certain Canadian motor vehicles and dairy products are scheduled from September 29.
Open trade counsel from Osler and World Trade Scanner puts the September 15 modification at 122 newly covered HTSUS classifications under headings 9903.03.12 and 9903.03.14.
Eleven classifications are removed from scope while the base 50 percent Section 338 rate on goods already in scope since August 22 continues.
Fertilizer Daily and prior USTR disclosures keep elemental sulfur, HS 2503, sulfuric acid, potash, energy, and critical minerals off the covered lists.
Canada remains the dominant US import source for recovered sulfur per USGS import-source tables.
Alberta forming plants and the Vancouver stem therefore watch list text even as the broader North American trade fight widens.
The September 15 expansion adds steel derivatives, wood products, semiconductors, and patented pharmaceuticals to the 338 regime per open counsel notes.
Goods subject to both Section 232 and Section 338 duties may face stacked rates on certain aluminum and steel classifications from September 15.
No exemption applies for USMCA-originating goods on newly covered lines, a screening detail for cross-border shippers ahead of the effective date.
Ottawa's September 8 retaliation table already kept HS 2503 at free on the Canadian side of the border.
Desk read: September 15 widens the trade war without pulling sulfur into the tariff lists yet. Alberta inventory and Vancouver exports still move on freight and Hormuz math, not Section 338 line changes.