A group of four senators led by Sen. Barbara BoxerBarbara BoxerFour more lawmakers say they’ve been sexually harassed by colleagues in Congress California Hispanics are the vanguard for a new political paradigm Trump riles Dems with pick for powerful EPA job 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 KlobucharReported pressure on CNN in Time Warner merger raises retaliation fears Dem sens demand answers over reports DOJ wanted CNN sold Ted Cruz, Debbie Dingell help Chuck Todd celebrate 70 years of 'Meet the Press' MORE (D-Minn.), Sheldon WhitehouseSheldon WhitehouseTech companies grilled over Russian election interference Hitting GOP, Dems pitch raising 401(k) caps Democrats double down on calls for Congress to protect Mueller 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) SandersWorld leaders reach agreement on trade deal without United States: report Sanders on Brazile revelations: DNC needs ‘far more transparency’ Sen. Warren sold out the DNC 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.