Private musems are facing congressional scrutiny over their tax-exempt status, with a top lawmaker questioning the public benefits of allowing benefactors to receive tax breaks for collections that the public might have only limited ability to view.

Sen. Orrin Hatch, the Republican chairman of the Senate Finance Committee, said Thursday that he had finished a review of tax-exempt private museums and told IRS Commissioner John Koskinen in a letter that he remains “concerned that this area of our tax code is ripe for exploitation.”