The Starbucks CEO, Howard Schultz, has agreed to testify before a Senate committee investigating the company’s intense opposition to national efforts to unionize its stores.

The Guardian reports that Senator Bernie Sanders had threatened to subpoena Schultz if he refused to appear before the U.S. Senate health, education, labor and pensions (Help) committee. Sanders said Schultz had “refused to answer any of the serious questions we have asked” for over a year.

Since late 2021, 290 Starbucks stores around the U.S. have won union elections, but dozens of workers and the Starbucks Workers United union have filed unfair labor practice charges with the National Labor Relations Board (NLRB) over alleged retaliatory firings, discipline, unilateral changes, store closures, refusing to bargain with the union and intimidation against workers’ efforts to form unions.

Nine decisions by NLRB administrative law judges so far have found Starbucks violated the National Labor Relations Act, and 22 Starbucks workers have received judgments ordering their reinstatement. No Starbucks appeals have yet overturned any rulings.

Read more: Starbucks Illegally Fired Workers Over Union, Judge Rules

Starbucks initially pushed back on efforts to compel Schultz to testify before the U.S. Senate Help committee, offering other Starbucks executives in lieu of Schultz. Sanders criticized Starbucks’ response.