On September 24, 2026, the Bureau of Industry and Security (BIS) published a temporary final rule at 91 FR 60505 establishing how the Department of Commerce will identify and restrict importers that stockpile polysilicon and polysilicon derivatives (Polysilicon Products) before the Section 232 minimum import prices and tariffs under Proclamation 11052 take effect on December 4, 2026. The rule caps weekly import volumes for new importers of record, creates a waiver process, and reminds customs brokers of their enforcement exposure. Importers of polysilicon, the covered HTSUS 3818 products, solar cells, and solar modules, along with the customs brokers that file their entries, are affected now. 

Key Takeaways 

  • BIS published a temporary final rule at 91 FR 60505 on September 24, 2026. It is effective September 22, 2026, through December 3, 2026. 
  • Commerce is monitoring existing importers of record (IORs). An IOR that Commerce determines is importing Polysilicon Products in volumes substantially greater than its historic averages will be prohibited from making further entries of those products prior to December 4, 2026. 
  • New IORs that registered with CBP on or after August 6, 2026, are prohibited from importing above fixed weekly quantities by HTSUS subheading, absent Commerce approval. 
  • Prohibited or restricted companies may apply to Commerce for a waiver at Polysilicon232@bis.doc.gov. Commerce intends to respond within 14 days of receipt. 
  • Customs brokers are named in the rule. CBP enforcement actions could potentially include license suspension or revocation proceedings or broker penalties.

The Window Between the Proclamation and December 4 

Proclamation 11052, “Adjusting Imports of Polysilicon and Its Derivatives Into the United States,” was signed on August 6, 2026 (91 FR 51975). The Proclamation imposed minimum import prices and tariffs on Polysilicon Products under Section 232 of the Trade Expansion Act of 1962 (19 U.S.C. 1862), effective December 4, 2026, and authorized the Secretary of Commerce, in coordination with CBP, to restrict imports from companies that are stockpiling those products before that date. 

In the rule, Commerce stated it is aware of trade data from the week after the Proclamation showing “dramatic increases in polysilicon imports from some IORs” compared with their historic weekly average volumes. Commerce invoked the foreign affairs function exemption and the good cause exceptions of the Administrative Procedure Act. The rule took effect on September 22, 2026, without prior notice and comment, and it expires December 3, 2026. 

How Commerce Will Identify Stockpiling 

Existing importers of record 

Commerce is monitoring imports of Polysilicon Products to identify IORs that are stockpiling in advance of December 4, 2026. Commerce will make a fact-specific determination of whether an IOR is importing in volumes substantially greater than its historic averages, based on factors that include, but are not limited to: 

  • the aggregate volume of Polysilicon Products the importer has imported since August 6, 2026; 
  • the weekly average volume the importer is importing since August 6, 2026; 
  • the weekly average volume the importer imported between January 1, 2026, and August 6, 2026; 
  • the weekly average volume the importer imported in 2025; and 
  • the use of affiliates that do not customarily import Polysilicon Products, or the use of new IORs to import Polysilicon Products. 

The rule does not state a numeric threshold for “substantially greater.” When Commerce makes a determination, it will provide CBP written notice, and CBP will notify the IOR and any customs brokers conducting business on behalf of the IOR. That IOR will be prohibited from making further entries of Polysilicon Products into the United States prior to December 4, 2026. 

CBP’s guidance in CSMS # 69994928 (September 22, 2026) states that CBP will not allow a restricted IOR to make entries of these products until December 4, 2026. The same message states that restricted IORs may move the goods to a bonded warehouse but may not enter them for consumption before December 4, 2026. 

New importers of record 

New IORs that registered with CBP on or after August 6, 2026, are prohibited, absent Commerce approval, from importing Polysilicon Products prior to December 4, 2026, in weekly volumes greater than the following quantities: 

Commerce stated these quantities are based on historic import data and that it may adjust them in the future if it determines an adjustment is necessary to address stockpiling. A new IOR that exceeds these quantities, absent approval from Commerce, will be prohibited from making further entries of Polysilicon Products prior to December 4, 2026. The rule also provides that Commerce and CBP shall coordinate to take action against importers and customs brokers that establish, use, or facilitate multiple importers of record or other arrangements for the purpose of circumventing the program. 

DTL’s read: The new-IOR quantities are small. A single commercial shipment of modules or cells can exceed the weekly cap. New entities created after August 6 to bring in solar or polysilicon product should plan shipment sizing, or a waiver, before goods arrive. 

Customs Brokers Are Named in the Rule 

The rule addresses customs brokers that enter Polysilicon Products or act as the importer of record between September 22, 2026, and December 4, 2026, and reminds them of their affirmative obligation to avoid facilitating violations of the new-IOR limits. In determining whether a new IOR may be attempting to use its services to violate the rule, a customs broker should consider: 

  • Status: whether the IOR was established on or after August 6, 2026; 
  • Import behavior: whether the new IOR has made other entries of Polysilicon Products during the current week and, if so, the precise volume entered; 
  • Ownership: the direct and indirect beneficial owners of the new IOR, whether those owners have created other new IORs to import Polysilicon Products, and whether those IORs have met or exceeded the weekly quantities; and 
  • Disposition of the merchandise: the ultimate consignee and delivery user, and whether the goods will be transferred to or used for the benefit of an IOR subject to a prohibition. 

Under the rule, actions by customs brokers to evade the prohibition may result in CBP enforcement actions. Commerce stated these could potentially include, but are not limited to, proceedings to revoke or suspend the customs broker’s license under 19 CFR 111.53 or a broker penalty under 19 U.S.C. 1641. The rule also restates the 19 CFR 111.32 prohibition on filing documents known by the customs broker to be false, and reminds customs brokers not to give information they know or should know to be false or misleading in any matter pending before DHS. 

DTL’s read: We expect customs brokers to ask new and existing polysilicon and solar clients for beneficial ownership information, weekly entry volumes, and delivery details before filing. Importers that have this information ready will be in a better position to avoid entry delays. 

Requesting a Waiver from Commerce 

Companies that are prohibited or restricted from importing Polysilicon Products prior to December 4, 2026, may apply to Commerce for a waiver. For an existing IOR subject to a prohibition, a waiver allows the company to resume importing. For a new IOR subject to the weekly quantity restriction, a waiver allows the company to import in quantities subject to the stockpiling restrictions that apply to existing IORs. 

BIS will receive applications between September 22, 2026, and December 3, 2026. Applications are available at www.bis.gov/232 and must be submitted to Polysilicon232@bis.doc.gov. Under the rule, a valid application must, among other requirements: 

  • be submitted in PDF format, limited to 30 pages inclusive of attachments, with a non-confidential public version of any business confidential submission; 
  • include the applicant’s weekly average import volumes for 2025, for January 1 through August 6, 2026, and since August 6, 2026, plus the aggregate volume since August 6, 2026; 
  • provide the eight-digit or ten-digit HTSUS classification and a precise description of the products; 
  • explain how the company intends to use the imports, including annual production volume and capacity rates for each U.S. facility receiving them; 
  • disclose the use of affiliates or new IORs, and estimate import volumes through December 4, 2026, if a waiver is granted; 
  • explain the business considerations for the company’s import volumes (for existing IORs, why post-August 6 volumes were grounded in legitimate commercial considerations unrelated to the Proclamation; for new IORs, why the company became a new IOR and whether its U.S. customer relationships predate August 6, 2026); and 
  • be signed by a senior official certifying accuracy, and include a commitment not to stockpile Polysilicon Products prior to December 4, 2026. 

If an application is incomplete or improperly filed, the applicant may, at the discretion of the Under Secretary for Industry and Security, be granted a 48-hour window to resubmit. Commerce may request supplemental information, and it intends to respond to applications within 14 days of receipt. Commerce stated it will protect the confidentiality of information submitted by companies pursuing a waiver. 

DTL’s read: The rule describes waivers for companies that are already prohibited or restricted. New IORs are restricted from the date of registration, so they can apply before exceeding the weekly caps. For existing IORs, the rule does not describe an advance waiver before a prohibition is imposed. With the program ending December 3, a 14-day response target and a possible supplemental request can consume a meaningful share of the remaining window. 

Action Items for Solar and Polysilicon Importers 

DTL recommends the following steps now: 

  1. Run your own numbers first. Calculate your weekly average imports by HTSUS for 2025, for January 1 through August 6, 2026, and since August 6, 2026. These are the same metrics Commerce lists in the rule and in the waiver application. 
  2. Document the commercial reason for any increase. Gather purchase orders, supply contracts, and project schedules that predate August 6, 2026. If Commerce issues a prohibition, this file becomes the core of a waiver application. 
  3. Confirm your IOR registration date. Any IOR established on or after August 6, 2026, is subject to the weekly caps regardless of the parent company’s import history. 
  4. Review affiliate and multi-IOR structures. The rule lists the use of affiliates and new IORs as a stockpiling factor and directs action against arrangements used to circumvent the program. 
  5. Coordinate with your customs broker. Provide ownership, weekly volume, and consignee information before entries are filed, not after a hold. 
  6. Plan for goods already in transit. Under CBP’s guidance, a restricted IOR may place goods in a bonded warehouse but may not enter them for consumption before December 4, 2026, when the Section 232 minimum import prices and tariffs take effect. 

Also in the rule: BIS removed the aluminum and steel inclusions process from Supplement No. 1 to 15 CFR part 705, consistent with Proclamation 11021 of April 2, 2026. 

How Diaz Trade Law Can Help 

Diaz Trade Law advises importers and customs brokers on Section 232 actions, CBP entry and admissibility issues, and enforcement matters across the solar supply chain, including our prior coverage of country-of-origin risk for solar cells and modules in EAPA Case 8163. If your company has received notice of a prohibition, is planning shipments as a new IOR, or needs to prepare a waiver application before December 3, contact us at info@diaztradelaw.com or 305-456-3830. 

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