A new portal has now launched where businesses can request refunds for tariffs that were ruled illegal by the Supreme Court in February.

A refund system for businesses that paid tariffs which the U.S. Supreme Court ruled President Donald Trump imposed without the constitutional authority to do so is scheduled to launch Monday.

The Labor Department’s inspector general’s office is nearing the end of a monthslong investigation into a whistle-blower’s allegations of professional misconduct by Ms. Chavez-DeRemer and her closest ...