WASHINGTON — Four bipartisan members of the US House of Representatives have asked US Customs and Border Protection (CBP) and the Internal Revenue Service (IRS) to increase scrutiny of imported solar “blue wafers”, including their product classification, applicable trade duties and eligibility for domestic manufacturing tax credits.

The lawmakers allege that certain nearly completed solar cells may be entering the United States under declarations identifying them as ordinary silicon wafers. Limited finishing work is then allegedly completed in the US before the products are treated as domestically manufactured solar cells for federal tax-credit purposes.

The development could lead to closer examination of Asian solar supply chains, actual manufacturing locations and production records. However, the US government has not announced a new general tariff, import prohibition or final product-classification decision in response to the letter.

Bipartisan Lawmakers Write to CBP and the IRS

According to information published on 16 July 2026 by the Democratic members of the US House Select Committee on the Strategic Competition Between the United States and the Chinese Communist Party , Democratic Representatives Ro Khanna and Marcy Kaptur joined Republican Representatives Mike Bost and Pat Harrigan in writing to CBP and the IRS.

The lawmakers allege that some nearly completed solar cells originating from China are being imported as wafers, subjected to further processing in the United States, and then used to claim federal Section 45X manufacturing tax credits intended for domestically produced solar cells.

A Reuters report independently confirming the contents of the letter described the disputed products as “blue wafers”—high-purity silicon slices that have completed certain important processing steps but have not necessarily undergone every stage required to produce a finished solar cell.

What Is a Solar “Blue Wafer”?

A typical solar manufacturing process begins with polysilicon, followed by the production of silicon ingots, wafers, solar cells and completed modules.

“Blue wafer” is not, by itself, a universally decisive customs classification. It is an industry term used to describe certain intermediate products that have already undergone some solar-cell processing.

The central issue is whether these products should be classified as ordinary silicon wafers when imported, or whether they have already acquired the essential characteristics of solar cells.

The classification could affect applicable anti-dumping or countervailing duties, the determination of a product’s country of origin, and whether subsequent manufacturing in the United States qualifies for domestic production tax incentives.

Three Main Actions Requested by Lawmakers

• CBP should identify the relevant imported products and determine whether applicable anti-dumping or countervailing duties should be assessed;
• The IRS should require companies claiming Section 45X solar-cell manufacturing tax credits to provide documentation proving that key manufacturing steps were completed in the United States;
• CBP and the IRS should issue public guidance explaining the classification and documentation standards for solar wafers, cells and related intermediate products.

The most accurate description at this stage is that US lawmakers are seeking stronger enforcement and investigation. It would be inaccurate to report that the United States has already banned blue-wafer imports or imposed a new tariff on all Asian solar products.

Why Does This Matter to the Global Solar Industry?

Solar manufacturing supply chains often extend across several countries. A silicon wafer may be produced in one country, processed into a solar cell in another, and assembled into a module in a third.

Trade authorities must therefore determine which manufacturing stages are sufficient to change the product’s characteristics and country of origin. If US agencies adopt a stricter interpretation, the implications may extend beyond a single customs classification.

Manufacturers and importers could be required to provide more detailed bills of materials, processing records, factory production data, supplier declarations, shipping documents and country-of-origin evidence.

Closer scrutiny could also raise compliance costs and extend the time required for solar products to enter the US market. The actual impact will depend on whether CBP, the IRS or other relevant agencies issue formal decisions.

What Could It Mean for Malaysia’s Solar Supply Chain?

The letter focuses on products that the lawmakers describe as originating from China or being connected to Chinese supply chains. It does not announce a new measure specifically targeting Malaysia.

Malaysia is nevertheless part of the global solar manufacturing network, and some solar cells and modules manufactured in Malaysia are exported to the United States.

If US authorities strengthen enforcement, Malaysian manufacturers, exporters and procurement companies serving the US market may need to examine the following areas more carefully:

• The processing stages completed before imported wafers enter Malaysia;
• The locations where the key solar-cell manufacturing processes are performed;
• Whether material and country-of-origin documentation supplied by vendors can be fully traced;
• Whether export declarations, commercial documents and factory production records remain consistent.

This does not mean solar products manufactured in Malaysia will automatically face new tariffs. The applicable trade treatment will depend on the product, manufacturing process, origin determination and specific export route.

Will Malaysian Solar Customers Be Directly Affected?

There is currently no evidence that the congressional letter will immediately change residential or commercial solar system prices in Malaysia. It also does not change Solar ATAP, SuRIA Home, Malaysian electricity tariffs or local programme eligibility.

If the United States eventually tightens its import rules, international suppliers may adjust the flow of solar products between different markets.

However, Malaysian solar system prices will continue to be influenced by manufacturing capacity, demand, foreign-exchange rates, logistics, module and inverter brands, warranties, site conditions and installation requirements.