In 2006, the Northwest Environmental Defense Center sued certain timber-industry related defendants claiming that their logging activities resulted in the discharge of pollutants without a permit into streams in state forests in Oregon where they were harvesting timber. In 2010, the Ninth Circuit overturned an Oregon federal district court's grant of a motion to dismiss the case, finding that ditches and culverts adjacent to logging toads were point sources which required federal National Pollutant Discharge Elimination System (NPDES) permits. On March 20, 2013, the United States Supreme Court issued its decision in Decker v. Northwest Environmental Defense Center, Case No. 11-338, overturning the Ninth Circuit's decision.

Decker is another in a series of disputes dating back thirty-five years over a United States Environmental Protection Agency (USEPA)-created exception to the Clean Water Act known as the "Silviculture Rule," which is codified at 40 C.F.R. § 122.27. See, e.g., NRDC v. Costle, 568 F.2d 1369 (D.C. Cir. 1977) (holding that USEPA lacks the authority to categorically exempt point source discharges from the NPDES program). USEPA intended the Silvicultural Rule to exempt certain activities related to the collection of natural resources like log sorting and storage and rock crushing and gravel washing from needing NPDES permits. In Decker, the defendants who operated various logging roads contended that the Silvicultural Rule foreclosed the need for them to secure NPDES permits, and that potential impacts to water quality posed by the roads could be managed by state-level best management practices. Defendants also contended that, even without the Silvicultural Rule, their activities were not "industrial activities" requiring NPDES permits under USEPA's Industrial Stormwater Rule, 40 C.F.R. § 122.26.

The Decker decision revolves around whether the literal wording of the Industrial Stormwater Rule could require logging roads to have permits even though USEPA intended for logging roads to be exempt from permitting. The Court found that USEPA's interpretation of the Industrial Stormwater Rule, which exempted "logging roads" from being "industrial" even though other logging-related facilities like sawmills were "industrial," was permissible. The Court noted that the "regulatory scheme, taken as a whole, leaves open the rational interpretation that the regulation extends only to traditionally industrial buildings such as factories and associated sites and relatively fixed facilities." The Court further noted that USEPA's attempts to revise its regulations during litigation to clarify that logging roads were exempt from regulation provided additional support to USEPA's long-standing interpretation.

A disinterested observer might find the decision unexceptional because USEPA never intended for logging roads to require NPDES permits; because Decker represents just another instance of the Supreme Court overturning the Ninth Circuit in an environmental case; or because USEPA published a final rule immediately prior to the Supreme Court's oral argument in Decker in an attempt to trump the Ninth Circuit's ruling. This, however, probably short-changes this decision.

While the outcome of the case may have been preordained, the decision is notable because it contains signposts for future changes in what has long been a staid area of the law. For almost seventy years since the Supreme Court's decision in Bowles v. Seminole Rock & Sand Co., 325 U.S. 410 (1945), agency interpretations of regulations previously issued by the agency were entitled to deference. Decker confirms that agencies continue to be entitled to deference in interpreting their own regulations. (See Slip. Op. at 14) (citing Chase Bank USA, N.A. v. McCoy, 562 U.S. __ (2011) (at Slip. Op. 12). But — as is emphasized in concurring and dissenting opinions signed by three members of the Court — the era of unquestioned deference to agency interpretations of ambiguous regulations may soon come to a close. (See Justice Roberts' concurrence joined by Justice Alito, and Justice Scalia's solo concurrence and dissent).