DES MOINES, Iowa (AP) — Sen. Charles Grassley is expressing concern about President Donald Trump’s nominee for U.S. Secretary of Labor, questioning Eugene Scalia’s record on whistleblower protections. Grassley said Wednesday on a call with reporters that he’s concerned about briefs Scalia wrote while serving as the top lawyer at the Labor Department during the George W. Bush administration.

Grassley says Scalia argued that some whistleblower disclosures made to Congress aren’t protected under federal whistleblower laws and that the separation of powers doctrine prevents whistleblowers from disclosing certain information to Congress. Grassley, author of some current whistleblower protection laws, says it’s extremely important that Scalia would enforce whistleblower laws critical to ensuring public safety and preventing waste, fraud and abuse.

Scalia, son of late Supreme Court Justice Antonin Scalia, will appear before a Senate confirmation committee hearing on Thursday.