Court lets stand endangerment finding and rules regulating emissions from automobile tailpipes.

On 15 October 2013 The US Supreme Court announced it will review the federal government’s power to regulate greenhouse gases from fixed, stationary sources in an effort to head off global warming. The Justices accepted six petitions for review, but said they would consider only a single question for all of them.

The granted issue is: “Whether EPA permissibly determined that its regulation of greenhouse gas emissions from new motor vehicles triggered permitting requirements under the Clean Air Act for stationary sources that emit greenhouse gases.”

In order to understand why the Court agreed to consider this “permissibly granted” question, it’s worth reviewing the history of what led to the EPA regulations according to a post on the Web site “Legal Planet.”

First, the Court’s decision in Massachusetts v. EPA directed EPA to decide whether greenhouse gases are pollutants that must be regulated under the federal Clean Air Act. EPA then found that greenhouse gases endanger public health and welfare. The endangerment finding was upheld by the D.C. Circuit and the Supreme Court let stand that portion of the D.C. Circuit’s opinion.

EPA’s next decision was to issue the “tailpipe rule” that establishes greenhouse gas emissions standards for automobiles under the CAA. The lower court held that the CAA required the EPA to regulate greenhouse gas tailpipe emissions – that EPA had no choice under the language of the statute. The tailpipe rules, too, remain untouched.

The third and fourth rules are what will be at issue before the Supreme Court. Those rules are known as the “timing” and “tailoring” rules. They work together roughly as follows:

• Under EPA’s view, the regulation of greenhouse gases for automobiles automatically triggers a different section of the CAA, what is known as the prevention of significant deterioration (PSD) section which requires the EPA to regulate the emissions of any “major” source of a regulated pollutant. “Major” is defined in the CAA as any source that emits 100 tons per year of a regulated pollutant.
• The problem for the EPA is that the 100 tons per year amount would subject very, very small sources to the permitting provisions of the CAA, something that small sources have never had to comply with and that would be extremely expensive and administratively burdensome.
• So in the “tailoring” rule, the EPA only subjected large sources – new sources emitting 100,000 tons per year or more and existing sources making modifications that would increase emissions by 75,000 tons per year or more – to its greenhouse gas rules.

The lower court found that the EPA is legally justified – indeed required – to regulate greenhouse gas emissions from stationary sources under the PSD provisions of the act. The Supreme Court will now decide whether that ruling – that the PSD provisions must be used to regulate greenhouse gases – is correct.

What this means to you

Stationary sources include a great many industrial engine applications. Without EPA’s tailoring rule, these engines could be considered a major source under the CAA’s prevention of significant deterioration section and could therefore be subject to stricter emission limits.