In a public letter addressed to Ford boss Jim Farley, House Republicans Mike Gallagher and Jason Smith announced that two congressional committees are investigating the automaker’s licensing deal with Chinese battery maker CATL.

The probe centers on Ford’s efforts to put CATL’s battery cell technology to use at an upcoming, $3.5 billion battery cell plant in Michigan.

In their letter, the chairs of the House Ways and Means Committee and Select Committee on China call on Ford to hand over details on its agreement with CATL by August 10. 

The representatives have asked for communications between Ford and the Biden administration relating to the CATL deal. They further called on Ford to explain how it will “ensure imports from CATL to produce LFP batteries in Michigan are free of forced labor or inputs from Xinjiang.”

Reached by TechCrunch, a Ford spokesperson declined to comment on the specifics of the letter. The spokesperson reiterated a statement that the automaker “alone is investing $3.5 billion and will own and run this plant in the United States, instead of building a battery plant elsewhere or exclusively importing LFP batteries from China like our competitors do.” 

Earlier this week, House Republicans announced a separate investigation into U.S. venture firms’ investments in China.