U.S. EPA today outlined its legal arguments in defense of two of its key greenhouse gas regulations.

The agency filed its brief with the U.S. Court of Appeals for the District of Columbia Circuit in litigation over the "timing" and "tailoring" rules.

The former required that new controls of greenhouse gas emissions from stationary sources be triggered on Jan. 2, 2011, the day that new motor vehicle standards went into effect, while the latter interprets the Clean Air Act in such a way that only major polluters are required to obtain permits for greenhouse gas emissions.

The rules are two of four under legal attack from various industry groups in three separate cases before the appeals court (Greenwire, March 23).

Of the four, the tailoring rule is seen by legal experts as most vulnerable because the Obama administration essentially had to amend the Clean Air Act to get the outcome it wanted.

The alternative would have been that nonindustrial sources like schools and apartments would have been subject to regulation.

In the brief, government lawyers argue that EPA was merely following congressional intent and did not overstep the boundaries of its authority when it issued the tailoring rule.

EPA says that various courts, including the D.C. Circuit, "have developed a number of doctrines that directly address the situation where an agency finds it impossible to administer a statute precisely as Congress specified."

The agency also argues that the various challengers lack standing to challenge both rules because they cannot show they have suffered an injury.

Click here to read the brief.