Navistar: Legal flaws doom SCR and NOx standard

Updated Jan 6, 2010

In a brief filed in November in its ongoing litigation with the U.S. Environmental Protection Agency, truck and engine maker Navistar argued that EPA violated federal law not only by allowing its competitors to use selective catalytic reduction (SCR) as their solution for achieving reductions in oxides of nitrogen (NOx) but also by continuing to insist on an emissions standard of 0.2 grams of NOx per brake-horsepower-hour.

Navistar is suing EPA in the U.S. Court of Appeals for the District of Columbia Circuit on the grounds that the agency issued without providing the opportunity for public comments a guidance document in February 2009 setting the conditions under which truck and engine manufacturers could use SCR to comply with the 0.2 gram standard. The guidance document allows SCR-equipped engines to exceed the 0.2 gram standard for brief periods to allow for truck owners and drivers to refill diesel exhaust fluid or repair emissions-related hardware problems.

In its Nov. 20 brief, Navistar contends that EPA was clear in its 2001 rule that SCR aftertreatment would not be a feasible means of achieving the NOx standard on a fleetwide basis. Rather, EPA believed that NOx adsorbers would be the emissions solution. In the years since, however, most truck manufacturers have pursued SCR, and NOx adsorbers have been abandoned as a 2010 solution.

Since EPA has not initiated any public rulemaking to reconsider its determination that SCR is infeasible, the February 2009 guidance is illegal, Navistar argues. “Indeed, it is no exaggeration to say that the 2009 Guidance reads as a blueprint for designing an engine that violates the 2001 Rule but that nevertheless will be granted a certificate of conformity with that Rule.”

Navistar goes further, however, by arguing that the entire 0.2 gram standard itself is now invalid because neither of the two control technologies EPA has identified for achieving the standard is available.

In October, EPA asked the appeals court for a stay in the litigation while it reconsiders the guidance, but Navistar opposed the request, and the court had not acted on it. (For more on the EPA motion, see Journal, CCJ December 2009).