Two Texas Republicans, Reps. August Pfluger and Michael McCaul, are seeking answers from U.S. Customs and Border Protection (CBP) about how the agency screens critical minerals imported from China.

The Republicans sent a letter, obtained by Breitbart News, to CBP Commissioner Chris Magnus on Friday demanding he lay out how the imports are screened to prevent United States importation of critical minerals produced by way of Chinese forced labor.

“Due to the importance of critical minerals to such a broad range of applications, the Chinese Communist Party leadership has long made dominating the supply chain a priority,” Pfluger and McCaul began their letter.

That China has a “stranglehold” on critical minerals is due “in no small part … to the CCP’s unfair trade practices, minimal concern for environmental standards, huge state financial backing for Chinese critical mineral firms, and the use of forced labor,” they wrote.

Read a copy of the letter below:

America relies heavily on China for critical minerals, which are used in the defense and tech industries to manufacture a wide range of products, from fighter jets and night vision goggles to electric vehicles.

Pfluger and McCaul, who both sit on the Homeland Security and Foreign Affairs Committees, cited reports from the New York Times and Bloomberg Law that revealed this summer, as the Uyghur Forced Labor Prevention Act went into effect, “red flags” in the connection between forced labor and Chinese critical mineral production.

The forced labor bill was signed into law last year in an effort to ban products sourced to Xinjiang — the Chinese province found to be committing atrocious human rights abuses, including forced labor, against Uyghur Muslims — unless importers could provide “clear and convincing evidence” the products were not a result of forced labor.

“Although Xinjiang-originated polysilicon and cotton have received the most attention, recent reports combined with the extreme difficulty in tracing the supply chain for critical minerals indicate an extremely high risk that imports of these products could violate the Act,” the Republicans wrote.

They demanded Magnus respond to them by mid-October with details of how CBP is screening imports of critical minerals originating from China and an answer on if Magnus believes the materials are at “substantial risk” of being tied to forced labor.

Write to Ashley Oliver at aoliver@breitbart.com. Follow her on Twitter at @asholiver.