Trump Administration Initiates Section 232 Investigations on Polysilicon and Unmanned Aircraft Systems

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On July 14, 2025, the US Department of Commerce Bureau of Industry and Security (BIS) announced the initiation of investigations into the effects on US national security of (i) imports of polysilicon and its derivatives,1 and (ii) imports of unmanned aircraft systems (UAS) and their parts and components.2 The investigations could result in the imposition of tariffs or other import restrictions. BIS is conducting the investigations under Section 232 of the Trade Expansion Act of 1962, a law that empowers the president to restrict imports of products that threaten to impair national security.3 Section 232 investigations can take up to 270 days to complete (setting the latest date for completion in March 2026), but the Trump administration has signaled it intends to move faster. Like other recent Section 232 investigations, the two new initiation notices provide unusually short timespans for public comments and do not reference any plans to hold public hearings.

The polysilicon and polysilicon derivatives investigation

The initiation notice describes the investigation as targeting “polysilicon and its derivatives,” without any further details.

Polysilicon is a key input in semiconductors and solar panels, both of which the US government has been attempting to protect from import competition in recent years. President Biden increased Section 301 tariffs on imports from China of polysilicon, wafers, and solar cells (whether or not assembled into modules) from 25% to 50% on January 1, 2025, and increased the Section 301 tariff on semiconductors from China from 25% to 50% on September 27, 2024. Solar imports from China and Southeast Asia also face substantial antidumping and countervailing duties.

A Section 232 investigation of semiconductors and semiconductor manufacturing equipment is already underway.4 Semiconductor substrates and wafers fall within this existing investigation, suggesting the new polysilicon investigation could be targeting the solar power supply chain specifically. Since 2018, the United States has used a safeguard action to impose tariffs and tariff-rate-quotas on imports of most solar panels, modules, and cells from most countries (in addition to the China-specific Section 301 tariffs and antidumping and countervailing duties).5 The safeguard action is limited under US law to a maximum length of eight years, and it will expire in February 2026.

The UAS and UAS parts and components investigation

The initiation notice describes the investigation as targeting “unmanned aircraft systems (UAS) and their parts and components,” without any further details.

In recent years, the United States has adopted a series of national security measures targeting certain UAS technologies from certain countries of concern (such as China), mostly through export control and government procurement restrictions. Most recently, in November 2024, the Federal Acquisition Regulatory Council began implementing the 2024 National Defense Authorization Act’s (NDAA) procurement limits on certain foreign UAS, prohibiting federal procurement, operation, or the use of federal funding for procurement or operation of UAS from designated foreign entities.6

Other national security actions are under development, which would include expanding restrictions on the commercial UAS market. The 2025 NDAA, passed into law in December 2024, instructed the Federal Communications Commission (FCC) to add several China-linked UAS companies to the Covered List under Section 2 of the Secure Networks Act by the end of 2025.7 Adding these entities to the Covered List would prohibit the FCC from issuing equipment authorizations for covered telecommunications equipment and video surveillance products, essentially excluding the covered products from the US market. Meanwhile, BIS is considering using the ICTS Rule to impose transaction restrictions on certain information and communications technologies and services used in UAS that are provided by persons owned by, controlled by, or subject to the jurisdiction or direction of foreign adversaries.8 An ICTS Rule-based prohibition could have broader implications than an action taken under the FCC Covered List, although details of BIS’ plans are not yet available.

The Trump administration highlighted a few of these pending actions in recent executive orders that aim to promote the development of US UAS and supersonic flight industries.9 Among other actions, the executive order on “Unleashing American Drone Dominance”10 instructs the Department of Commerce to “take actions, including proposing rulemaking and conducting investigations, to secure the United States drone supply chain against foreign control or exploitation.” The reference to Department of Commerce investigations likely implies a desire by President Trump for a Section 232 investigation (as well as the ICTS Rule investigation), but the executive order does not cite any statue directly.

Opportunity for public comments

Interested stakeholders may submit comments through the two public dockets at Regulations.gov. Comments are due by August 6, 2025. The notices provide additional instructions on how to participate and submit comments. BIS will consider and respond to public comments as it conducts the investigations. Participating in the public comment process can help shape the outcome of the investigation and prompt regulators to further clarify actions. BIS’ responses may also inform any potential legal challenge should a final action be adopted. The BIS notices do not mention any prospective public hearings for either of the investigations (public hearings are discretionary for Section 232 investigations).

The notices highlight that BIS is especially interested in comments that directly address the regulatory criteria for determining the effects of imports on national security:

  • For the polysilicon and polysilicon derivatives investigation, the notice states that comments addressing the regulatory criteria could include answering questions related to: “(i) the current and projected demand for polysilicon and its derivatives in the United States; (ii) the extent to which domestic production of polysilicon and its derivatives can meet domestic demand; (iii) the role of foreign supply chains, particularly of major exporters, in meeting United States demand for polysilicon and its derivatives; (iv) the concentration of U.S. imports of polysilicon and its derivatives from a small number of suppliers and the associated risks; (v) the impact of foreign government subsidies and predatory trade practices on the competitiveness of the polysilicon and its derivatives, in the United States; (vi) the economic impact of artificially suppressed prices of polysilicon and its derivatives due to foreign unfair trade practices and state-sponsored overproduction; (vii) the potential for export restrictions by foreign nations, including the ability of foreign nations to weaponize their control over supplies of polysilicon and its derivatives; (viii) the feasibility of increasing domestic capacity for polysilicon and its derivatives to reduce import reliance; (ix) the impact of current trade policies on domestic production of polysilicon and its derivatives, and whether additional measures, including tariffs or quotas, are necessary to protect national security; and (x) any other relevant factors.”
  • For the UAS and UAS parts and components investigation, the notice states that comments addressing the regulatory criteria could include answering questions related to: “(i) the current and projected demand for UAS and their parts and components in the United States; (ii) the extent to which domestic production of UAS and their parts and components can meet domestic demand; (iii) the role of foreign supply chains, particularly of major exporters, in meeting United States demand for UAS and their parts and components; (iv) the concentration of U.S. imports of UAS and their parts and components from a small number of suppliers or foreign nations and the associated risks; (v) the impact of foreign government subsidies and predatory trade practices on the competitiveness of the UAS and their parts and components industry, in the United States; (vi) the economic impact of artificially suppressed prices of UAS and their parts and components due to foreign unfair trade practices and state-sponsored overproduction; (vii) the potential for foreign nations and companies to weaponize their control over supplies of UAS and their parts and components; (viii) the potential for foreign nations and companies to weaponize the capabilities or attributes of foreign-built UAS systems and their parts or components; (ix) the feasibility of increasing domestic capacity for UAS and their parts and components to reduce import reliance; (x) the impact of current trade policies on domestic production of UAS and their parts and components, and whether additional measures, including tariffs or quotas, are necessary to protect national security; and (xi) any other relevant factors.”

The Trump administration’s Section 232 tariffs

In recent months, the Trump administration has appeared to move towards a two-track tariff strategy, imposing (i) “baseline” and “reciprocal” tariffs on most products from most countries under the International Emergency Economic Powers Act (IEEPA), apparently seeking to negotiate more favorable market access conditions in return for the lifting of the tariffs;11 and (ii) Section 232 tariffs on imports associated with industries the Trump administration views as strategically important. Unlike most other tariffs President Trump has imposed, the “baseline” / “reciprocal” tariffs and the Section 232 tariffs do not “stack” on top of each other. Instead, products affected by Section 232 tariffs are exempt from the “baseline” and “reciprocal” tariffs.

The UAS and polysilicon Section 232 investigations are the latest in a series of sector-specific tariff actions the under the Trump administration. Since taking office on January 20, President Trump has expanded the Section 232 tariffs on steel and aluminum and revived a Section 232 investigation from his first term to impose tariffs on imports of passenger vehicles, light trucks, and certain automotive parts. Other ongoing investigations target imports of copper and copper derivative products; timber, lumber, and wood products; semiconductors and semiconductor manufacturing equipment; pharmaceuticals and pharmaceutical ingredients; processed critical minerals and downstream products; trucks and truck parts; commercial aircraft and jet engines and parts for commercial aircraft and jet engines.

Though the rules allow up to 270 days to complete a Section 232 investigation and another 90 days for the president to make a policy determination, the Trump administration has moved unusually quickly with these new investigations. At least a few appear to be nearing completion already, which could lead to the imposition of new tariffs as soon as August. On July 9, 2025, President Trump posted on Truth Social12 that he will impose a 50% Section 232 tariff on copper imports beginning on August 1, 2025 (though he has yet to issue legal orders to implement the action). BIS launched the copper investigation on March 10, 2025, meaning the investigation and policy determination process took about 121 days. Secretary of Commerce Howard Lutnick has also recently stated that BIS will deliver its investigation reports for pharmaceuticals and semiconductors by the end of July.

1 “Notice of Request for Public Comments on Section 232 National Security Investigation of Imports of Polysilicon and its Derivatives,” 90 FR 31955 (July 16, 2025).
2 “Notice of Request for Public Comments on Section 232 National Security Investigation of Imports of Unmanned Aircraft Systems (UAS) and Their Parts and Components,” 90 FR 31958 (July 16, 2025).
3 19 U.S.C. §1862; and 15 C.F.R. part 705. More information on BIS’ Section 232 activities can be found on the BIS website.
4 “Notice of Request for Public Comments on Section 232 National Security Investigation of Imports of Semiconductors and Semiconductor Manufacturing Equipment,” 90 FR 15950 (April 16, 2025).
5 Quota Bulletin: 25-507 2025 Solar Cells and Modules, CBP.
6 “Federal Acquisition Regulation: Prohibition on Unmanned Aircraft Systems From Covered Foreign Entities,” 89 FR 89464 (November 12, 2024).
7 “List of Equipment and Services Covered by Section 2 of The Secure Networks Act,” FCC.
8 “Securing the Information and Communications Technology and Services Supply Chain: Unmanned Aircraft Systems,” 90 FR 271 (January 3, 2025).
9 For further discussion of these executive orders, see White & Case’s Client Alert at “President Trump issues Executive Orders to promote the development of Unmanned Aircraft Systems and Supersonic Flight.”
10 Executive Order 14307 of June 6, 2025: “Unleashing American Drone Dominance,” 90 FR 24727.
11 Executive Order 14257 of April 2, 2025: “Regulating Imports With a Reciprocal Tariff To Rectify Trade Practices That Contribute to Large and Persistent Annual United States Goods Trade Deficits,” 90 FR 15041 (April 7, 2025).
12 Truth Social post of July 9, 2025.

We provide below a list of partners and senior attorneys within the Global International Trade Practice of White & Case. Please contact any of them with questions about this report or other trade issues.

White & Case means the international legal practice comprising White & Case LLP, a New York State registered limited liability partnership, White & Case LLP, a limited liability partnership incorporated under English law and all other affiliated partnerships, companies and entities.

This article is prepared for the general information of interested persons. It is not, and does not attempt to be, comprehensive in nature. Due to the general nature of its content, it should not be regarded as legal advice.

© 2025 White & Case LLP

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Ian Saccomanno
Ian Saccomanno
Senior Trade Analyst|Washington, DC
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