U.S. expands and reshuffles 50% Section 338 tariffs on Canadian goods, adding many HTS lines and removing several others effective Sept. 15, 2026.

1. What changed

The President issued a proclamation modifying the scope of Canadian-origin products subject to additional ad valorem duties under Section 338 of the Tariff Act of 1930, originally imposed by Proclamation 11048. The 50% ad valorem duty rate remains unchanged, but the list of covered and excluded HTSUS subheadings is significantly revised via Annex I and Annex II.

Key elements:

• Certain Canadian-origin products listed in Annex I, Part A are newly subject to a 50% ad valorem additional duty under Section 338.
• Certain Canadian-origin products listed in Annex I, Part B are removed from Section 338 coverage and no longer subject to the 50% additional duty.
• Subchapter III of Chapter 99, HTSUS, including U.S. note 51 and heading 9903.03.13, is modified to reflect these changes.
• Section 338 duties apply in addition to any existing Section 232 duties.

Effective date:

• Applies to goods entered for consumption, or withdrawn from warehouse for consumption, on or after 12:01 a.m. Eastern Time on September 15, 2026.
• Modifications remain in effect until expressly suspended, revoked, supplemented, amended, or terminated.

2. Affected products

A. Newly covered by 50% Section 338 duty (Annex I, Part A / Annex II insertions)

These products of Canada are now subject to an additional 50% ad valorem duty when entered into the U.S., unless qualifying as civil aircraft/parts under HTSUS General Note 6. Key HTSUS subheadings include:

Dairy and food products

• 0406.90.99 – Other cheeses and substitutes for cheese (including mixtures), not made from cow’s milk, nesoi, not described by general U.S. note 15.

Paper and paperboard

• 4802.61.10 – Writing and cover paper in rolls over 15 cm wide, >10% mechanical/chemi-mechanical fiber.
• 4802.61.20 – Drawing paper in rolls over 15 cm wide, >10% mechanical/chemi-mechanical fiber.
• 4802.61.60 – Paper or paperboard for writing, printing or other graphic purposes, nesoi, in rolls not over 15 cm wide, >10% mechanical/chemi-mechanical fiber.
• 4802.62.10 – Writing and cover paper in sheets with sides not exceeding 435 mm and 297 mm, >10% mechanical/chemi-mechanical fiber.
• 4802.62.20 – Drawing paper in sheets with sides not exceeding 435 mm and 297 mm, >10% mechanical/chemi-mechanical fiber.
• 4802.62.30 – Paper and paperboard for graphic purposes, nesoi, in sheets with sides not exceeding 435 mm and 297 mm, >10% mechanical/chemi-mechanical fiber.
• 4802.62.61 – Paper or paperboard for graphic purposes, nesoi, in sheets with sides not exceeding 360 mm and 150 mm, >10% mechanical/chemi-mechanical fiber.
• 4802.69.10 – Writing and cover paper in sheets, nesoi, >10% mechanical/chemi-mechanical fiber.
• 4802.69.20 – Drawing paper in sheets, nesoi, >10% mechanical/chemi-mechanical fiber.
• 4802.69.30 – Paper and paperboard for graphic purposes in sheets, nesoi, >10% mechanical/chemi-mechanical fiber.

Iron/steel and aluminum structures and profiles

• 7308.90.30 – Iron or steel columns, pillars, posts, beams and girders, not in part of alloy steel.
• 7308.90.60 – Iron or steel columns, pillars, posts, beams and girders, nesoi.
• 7308.90.95 – Iron or steel structures (excluding prefabricated structures) and parts of structures, nesoi.
• 7604.10.10 – Aluminum non-alloyed profiles.
• 7604.10.30 – Aluminum non-alloyed bars and rods, with a round cross section.
• 7604.10.50 – Aluminum non-alloyed bars and rods, without a round cross section.
• 7604.21.00 – Aluminum alloy hollow profiles.
• 7604.29.10 – Aluminum alloy profiles (other than hollow profiles).
• 7604.29.30 – Aluminum alloy bars and rods, with a round cross section.
• 7604.29.50 – Aluminum alloy bars and rods, without a round cross section.
• 7608.10.00 – Aluminum non-alloyed tubes and pipes.
• 7608.20.00 – Aluminum alloy tubes and pipes.

Flexible tubing and fasteners

• 8307.10.30 – Iron or steel flexible tubing, with fittings.
• 8307.90.30 – Base metal (other than iron or steel) flexible tubing, with fittings.
• 8308.10.00 – Base metal hooks, eyes and eyelets for clothing, footwear, awnings, handbags, travel goods or other made up articles.
• 8308.20.30 – Iron or steel tubular or bifurcated rivets, not brightened, lathed or machined.
• 8308.20.60 – Base metal tubular or bifurcated rivets (other than of iron or steel).
• 8308.90.30 – Base metal beads and spangles.
• 8308.90.60 – Base metal buckles and buckle clasps, and parts thereof.
• 8308.90.90 – Base metal clasps, frames with clasps not incorporating a lock and like articles, and parts thereof.
• 8309.10.00 – Base metal crown corks (including crown seals and caps), and parts thereof.

Sign plates and welding materials

• 8310.00.00 – Base metal sign plates, name plates, address plates, numbers, letters and other symbols, and parts thereof.
• 8311.10.00 – Coated base metal electrodes for electric arc-welding.
• 8311.20.00 – Cored base metal wire for electric arc-welding.
• 8311.30.30 – Coated rods and cored wire lead-tin solders.
• 8311.30.60 – Coated rods and cored wire of base metal (other than lead-tin solders), for soldering, brazing or welding by flame.

Electrical switchgear

• 8537.10.9130
• 8537.10.9150
• 8537.10.9160
• 8537.10.9170

(These are specific subcategories of switchgear assemblies and switchboards for a voltage not exceeding 1,000 V; see Annex II for exact tariff text.)

Vehicles and boats

• 8703.10.50 – Golf carts and similar motor vehicles.
• 8703.21.01 – Motor vehicles for the transport of persons, spark-ignition internal-combustion piston engine, cylinder capacity not exceeding 1,000 cc.
• 8903.99.21 – Outboard motorboats with a length 7.5 m and over.

Seats, furniture, mattresses, and parts

• 9401.41.00 – Wood seats convertible into beds (other than garden seats or camping equipment).
• 9401.49.00 – Non-wood seats convertible into beds (other than garden seats or camping equipment).
• 9401.52.00 – Bamboo seats.
• 9401.53.00 – Rattan seats.
• 9401.59.00 – Seats nesoi, of cane, osier or similar materials (other than bamboo or rattan).
• 9401.61.20 – Upholstered chairs nesoi, of teak.
• 9401.69.20 – Seats nesoi, of bent-wood.
• 9401.69.40 – Not-upholstered chairs nesoi, of teak.
• 9401.69.80 – Not-upholstered seats (other than chairs) nesoi, of wood.
• 9401.80.20 – Seats nesoi, of reinforced or laminated plastics.
• 9401.80.40 – Seats nesoi, of rubber or plastics (other than reinforced or laminated plastics).
• 9401.80.60 – Seats nesoi.
• 9401.91.15 – Wood parts of seats, nesoi, for seats of a kind used for motor vehicles.
• 9401.91.20 – Wood parts of seats, nesoi, for bent-wood seats.
• 9401.99.25 – Parts of seats, nesoi, of cane, osier, bamboo or similar materials.
• 9401.99.35 – Parts of seats, nesoi, of rubber or plastics.
• 9401.99.90 – Parts of seats, nesoi.
• 9403.30.40 – Office furniture (other than seats) of bent-wood, nesoi.
• 9403.40.40 – Kitchen furniture (other than seats) of bent-wood, nesoi.
• 9403.40.60 – Furniture (other than seats) of wood (other than bent-wood) nesoi, of a kind used in the kitchen or designed for motor vehicle use.
• 9403.60.40 – Furniture (other than seats) of bent-wood, nesoi.
• 9403.70.40 – Furniture (other than seats) of reinforced or laminated plastics, nesoi.
• 9403.82.00 – Bamboo furniture and parts.
• 9403.83.00 – Rattan furniture and parts.
• 9403.89.30 – Furniture (other than seats) of cane, osier or similar materials (other than bamboo or rattan).
• 9403.89.60 – Furniture (other than seats) of materials nesoi.
• 9404.10.00 – Mattress supports.
• 9404.21.00 – Mattresses of cellular rubber or plastics, whether or not covered.
• 9404.29.10 – Mattresses of cotton.
• 9404.29.90 – Mattresses not of cellular rubber, plastics or cotton.

Lamps and lighting

• 9405.21.40 – Electric table, desk, bedside or floor-standing lamps, of brass, designed solely for LED light sources.
• 9405.21.60 – Electric table, desk, bedside or floor-standing lamps, of base metal (other than brass), designed solely for LED light sources.
• 9405.21.80 – Electric table, desk, bedside or floor-standing lamps, not of base metal, designed solely for LED light sources.
• 9405.29.40 – Electric table, desk, bedside or floor-standing lamps, of brass, not designed solely for LED light sources.
• 9405.29.60 – Electric table, desk, bedside or floor-standing lamps, of base metal (other than brass), not designed solely for LED light sources.
• 9405.29.80 – Electric table, desk, bedside or floor-standing lamps, not of base metal, not designed solely for LED light sources.

Fishing equipment

• 9507.10.0040 – (Specific fishing rod parts/accessories subcategory; see Annex II for full description.)

B. Products removed from 50% Section 338 duty (Annex I, Part B / Annex II deletions)

These Canadian-origin products are no longer subject to the 50% Section 338 additional duty, but remain subject to normal MFN rates and any other applicable trade remedies (e.g., Section 232, ADD/CVD):

• 2501.00.00 – Salt and pure sodium chloride.
• 2523.29.00 – Portland cement (other than white cement), whether or not colored.
• 2940.00.60 – Chemically pure sugars, nesoi.
• 4803.00.40 – Toilet or facial tissue, towel or napkin stock and paper for household or sanitary purposes, in rolls or sheets, other than cellulose wadding.
• 4818.90.0080 – Bed sheets and similar household or hospital articles of paper pulp, paper, cellulose wadding or webs of cellulose fibers, nesoi.
• 7801.10.00 – Refined lead, unwrought.
• 8537.10.9120 – Switchgear assemblies and switchboards for a voltage not exceeding 1,000 V (specific subcategory).
• 9507.10.0080 – Fishing rod parts and accessories.

3. Rate changes

• Section 338 additional duty rate: 50% ad valorem.
• For newly covered HTS lines in Annex I, Part A, the additional duty changes from 0% to +50% ad valorem on Canadian-origin goods, in addition to any existing base duty and other trade remedies.
• For HTS lines in Annex I, Part B, the additional duty changes from +50% back to 0% under Section 338 (normal MFN and other applicable duties still apply).
• The proclamation confirms that Section 338 duties are cumulative with Section 232 duties where applicable.

4. Dates

• August 19, 2026: Original Section 338 duties under Proclamation 11048 were scheduled to take effect.
• August 18–21, 2026: Temporary 3-day suspension under Proclamation 11056; suspension lapsed at 12:01 a.m. ET on August 22, 2026, and original duties became effective.
• September 8, 2026: Date of this modifying proclamation.
• September 15, 2026, 12:01 a.m. ET: Effective date for the modified product scope and HTSUS changes (Annex I and Annex II) for entries and warehouse withdrawals for consumption.
• Duration: Modifications remain in effect until expressly suspended, revoked, supplemented, amended, or terminated.

5. Required actions for importers, brokers, and compliance teams

Classification and HTS/Chapter 99 reporting

• Review all imports of Canadian-origin goods under the affected HTSUS subheadings listed above.
• For newly covered lines (Annex I, Part A / Annex II insertions), ensure:
• Correct 8-digit HTSUS classification is used.
• Applicable Chapter 99 Section 338 provision (e.g., 9903.03.13) is reported on entries for Canadian-origin goods.
• Systems and broker instructions are updated to automatically apply the 50% additional duty for qualifying Canadian-origin entries on/after September 15, 2026.
• For removed lines (Annex I, Part B / Annex II deletions), ensure:
• Chapter 99 Section 338 provisions are no longer applied to these HTS lines for entries on/after September 15, 2026.
• Entry software and broker instructions are updated to stop assessing the 50% additional duty on these HTS codes for Canadian-origin goods.

Origin and scope verification

• Confirm country of origin as Canada for all impacted products; Section 338 duties apply only to products of Canada.
• For aircraft and aircraft parts, verify whether they qualify under HTSUS General Note 6 (civil aircraft) to determine if they are excluded from Section 338 duties.
• For paper products, verify fiber content and dimensions to ensure correct classification within the 4802 subheadings.

Financial and supply chain planning

• Recalculate landed cost for all newly covered Canadian-origin products, incorporating the 50% ad valorem Section 338 duty plus any Section 232 or other duties.
• Assess alternative sourcing options (non-Canadian origin) where feasible to mitigate cost impact.
• Review pricing, contracts, and customer agreements to address increased duty costs on newly covered items and potential cost reductions where duties are removed.

Entry review and post-summary corrections

• For entries on or after September 15, 2026:
• Confirm that the correct Chapter 99 provisions and duty rates were applied.
• File post-summary corrections (PSCs) or protests where misapplication of Section 338 duties is identified.
• For entries of products removed from coverage (Annex I, Part B) that were entered on or after September 15, 2026 but still assessed Section 338 duties, evaluate opportunities for refunds via PSC or protest.

Internal controls and documentation

• Update internal compliance manuals and SOPs to reflect the new Section 338 product scope and HTSUS changes.
• Communicate changes to customs brokers, freight forwarders, and internal stakeholders (procurement, finance, logistics).
• Maintain documentation supporting classification, origin determination, and any civil aircraft exclusions under General Note 6.

Monitoring and future changes

• Monitor Federal Register notices from CBP for any additional HTSUS modifications, technical corrections, or implementation guidance as authorized by the proclamation.
• Track any subsequent presidential or USTR actions that may further modify Section 338 measures or related Chapter 99 provisions.

6. References

• Proclamation: “Modifying the Scope of Products of Canada Subject to the Additional Duties Imposed to Offset Canadian Discrimination Against the Commerce of the United States With Respect to Motor Vehicles,” September 8, 2026 (White House).
• Annex I (product lists – new and removed Section 338 coverage):

https://www.whitehouse.gov/wp-content/uploads/2026/09/ANNEX-I-AUTO.pdf

• Annex II (HTSUS Chapter 99 modifications, including U.S. note 51 and 9903.03.13 references):

https://www.whitehouse.gov/wp-content/uploads/2026/09/ANNEX-II-AUTO.pdf

7. HTS metadata

Explicitly affected HTS headings/subheadings referenced in the proclamation and annexes include:

• 0406.90.99
• 2501.00.00
• 2523.29.00
• 2940.00.60
• 4802.61.10
• 4802.61.20
• 4802.61.60
• 4802.62.10
• 4802.62.20
• 4802.62.30
• 4802.62.61
• 4802.69.10
• 4802.69.20
• 4802.69.30
• 4803.00.40
• 4818.90.00
• 4818.90.0020
• 7801.10.00
• 7308.90.30
• 7308.90.60
• 7308.90.95
• 7604.10.10
• 7604.10.30
• 7604.10.50
• 7604.21.00
• 7604.29.10
• 7604.29.30
• 7604.29.50
• 7608.10.00
• 7608.20.00
• 8307.10.30
• 8307.90.30
• 8308.10.00
• 8308.20.30
• 8308.20.60
• 8308.90.30
• 8308.90.60
• 8308.90.90
• 8309.10.00
• 8310.00.00
• 8311.10.00
• 8311.20.00
• 8311.30.30
• 8311.30.60
• 8537.10.91
• 8537.10.9120
• 8537.10.9130
• 8537.10.9150
• 8537.10.9160
• 8537.10.9170
• 8703.10.50
• 8703.21.01
• 8903.99.21
• 9401.41.00
• 9401.49.00
• 9401.52.00
• 9401.53.00
• 9401.59.00
• 9401.61.20
• 9401.69.20
• 9401.69.40
• 9401.69.80
• 9401.80.20
• 9401.80.40
• 9401.80.60
• 9401.91.15
• 9401.91.20
• 9401.99.25
• 9401.99.35
• 9401.99.90
• 9403.30.40
• 9403.40.40
• 9403.40.60
• 9403.60.40
• 9403.70.40
• 9403.82.00
• 9403.83.00
• 9403.89.30
• 9403.89.60
• 9404.10.00
• 9404.21.00
• 9404.29.10
• 9404.29.90
• 9405.21.40
• 9405.21.60
• 9405.21.80
• 9405.29.40
• 9405.29.60
• 9405.29.80
• 9507.10.00
• 9507.10.0040
• 9507.10.0080
• 9903.03.13

Importers should rely on the official HTSUS and annex PDFs for full legal descriptions and any additional Chapter 99 text needed for entry filing.