A group of four senators led by Sen. Barbara BoxerBarbara Levy BoxerKamala Harris endorses Gavin Newsom for California governor Dems face hard choice for State of the Union response Billionaire Steyer to push for Dem House push 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 Health Care: Trump eases rules on insurance outside ObamaCare | HHS office on religious rights gets 300 complaints in a month | GOP chair eyes opioid bill vote by Memorial Day Overnight Regulation: Trump to take steps to ban bump stocks | Trump eases rules on insurance sold outside of ObamaCare | FCC to officially rescind net neutrality Thursday | Obama EPA chief: Reg rollback won't stand Dems seek reversal of nursing home regulatory rollback MORE (D-Minn.), Sheldon WhitehouseSheldon WhitehouseCommittee chairman aims for House vote on opioid bills by Memorial Day Regulators seek to remove barriers to electric grid storage Prison sentencing bill advances over Sessions objections 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) SandersDems ponder gender politics of 2020 nominee 2020 Dem contenders travel to key primary states After Florida school shooting, vows for change but no clear path forward 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.