A group of four senators led by Sen. Barbara BoxerBarbara Levy BoxerThe ‘bang for the buck’ theory fueling Trump’s infrastructure plan Kamala Harris endorses Gavin Newsom for California governor Dems face hard choice for State of the Union response MORE (D-Calif.) are calling for the resignation of Environmental Protection Agency Administrator Stephen Johnson, saying that he gave misleading testimony to a Senate committee.

Johnson told the Senate Environment and Public Works Committee in January that he had denied a waiver to California that would have allowed it to enact its own fuel efficiency standards because the state failed to meet necessary criteria. But Boxer and three other senators said Wednesday that Johnson's testimony conflicted with that of an aide, who said that the waiver was denied partly because President Bush opposed it.

Boxer, chairwoman of the Senate Envionment and Public Works Committee, had supported the California standards, which are stricter than federal ones. She again chastised Johnson Tuesday for his decision.

"He has become a secretive and dangerous ally of polluters, and we cannot stand by and allow more damage to be done," she said in a statement. "We have lost all confidence in Stephen Johnson's ability to carry out EPA's mission in accordance with the law. I call on Administrator Johnson to immediately resign his position."

Sens. Amy KlobucharAmy Jean KlobucharOvernight Tech: Cambridge Analytica whistleblower meets House Dems | SEC fines Yahoo M over email breach | Senators unveil internet privacy bill Overnight Cybersecurity: Homeland Security official says Russia likely targeted more than 21 states | Senate approves Trump's NSA chief | Lawmakers unveil bipartisan internet privacy bill Senators introduce bipartisan internet privacy bill MORE (D-Minn.), Sheldon WhitehouseSheldon WhitehouseOvernight Energy: Pruitt proposes rule targeting 'secret science' | Dems probe Pruitt's security chief | FAA bill provisions could strip endangered species protections Dems say Pruitt security chief’s authorization for side job is invalid Overnight Energy: Dems raise new questions about Pruitt's security | EPA rules burning wood is carbon neutral | Fourth GOP lawmaker calls for Pruitt's ouster | Court blocks delay to car efficiency fines MORE (D-R.I.), and Frank Lautenberg (D-N.J.) joined Boxer's call for Johnson to step down.

The four Democrats and Sen. Bernie SandersBernard (Bernie) SandersWebb: Bernie Sanders announces his ‘new’ communism jobs, health-care plan A new progressive standard on campaign cash: It can't come from corporations Senate Health panel approves opioid bill MORE (I-Vt.) have also asked for a federal probe into whether Johnson's testimony was false or misleading. Download their letter to Attorney General Michael Mukasey here.