House oversight committee chair Henry A. Waxman (D-Calif.) is giving the White House one more chance to explain its role in the suspiciously weak air quality standards written by the EPA in mid-March.

The EPA is under the committee’s wrath for a number of decisions, but the ozone standard controversy is different. It appears that maligned EPA administrator Stephen Johnson approved an ozone standard slightly weaker than the recommendation of staff scientists. But then the White House- namely Office of Management and Budget Director Susan Dudley- stepped in and demanded a standard even more lax than what Johnson wanted.

Why did OMB do this? Did someone above Dudley tell her to intervene? The OMB’s answer so far is that it was a confidential decision made by the executive branch. Waxman is giving Dudley five more days to respond to his questions.

The endgame to this back and forth has implications beyond another case of White House stalling. Under the Clean Air Act, whatever ozone standard the EPA approves is law for ten years.