Senate Democrats are pushing to require President-elect Donald Trump’s Cabinet nominees to release their tax returns, something Trump refused to do during his campaign.

Currently the only Senate committees that can require such information are Finance, Budget, and Homeland Security and Governmental Affairs. But Democrats want to expand that authority to other committees that hold confirmation hearings, and plan to propose changing the rules when committees convene for the next Congress in January.

[Trump Cabinet Tally]

Democratic ranking members of three committees said at a press conference Thursday that Trump’s nominees, especially those who are extremely wealthy, should be scrutinized for their financial dealings and potential conflicts of interests.

“We’ve never before seen a Cabinet like this that’s made up of so many wealthy insiders and big money interests,” said Michigan Democratic Sen. Debbie Stabenow, ranking member of the Agriculture Committee.