Arizona’s senators have called for a stop to a Department of Commerce investigation into Chinese solar panel manufacturers, saying it has spooked investors and stalled renewable energy projects.

The agency says that Chinese manufacturers send their products to other countries for additional work before they are shipped to the United States.

Investigators say that the additional work was minor, and the practice amounted to dodging tariffs.

The potential penalties are high enough to discourage investment, and have put the industry on its heels.

Several months ago, U.S. Sens. Mark Kelly and Kyrsten Sinema of Arizona joined other senators to pressure the Biden administration to wrap up the investigation and place a two-year pause on solar tariffs.

They recently asked the president to extend that two-year pause.