EPA revises emissions guidance

Navistar continues legal challenge over SCR

Final briefs in the litigation over EPA’s SCR guidance are due April 9 to the U.S. Court of Appeals for the District of Columbia, which could decide emissions technology at least in the near term depending on how it rules.

Under legal pressure from Navistar, the U.S. Environmental Protection Agency revised its 2010 engine emissions guidance regarding the number of miles and hours a vehicle using selective catalytic reduction technology can operate after the diesel exhaust fluid is exhausted. The original guidance issued in February 2009 required engine performance to be degraded after a truck travels 2,000 miles or 40 hours on an empty DEF tank. The revision removes this provision and eliminates specific limits on mileage or time trucks should operate with empty DEF tanks.

Navistar sued EPA over that guidance, saying that the agency could not allow SCR without an opportunity for public comment, such as through a formal rulemaking process. The truck maker, which is not using SCR to comply with 2010 emissions-reduction rules, argued that EPA’s regulation in 2001 stated that SCR would not be feasible.

In October, EPA asked a federal appeals court for a 60-day stay to halt legal proceedings, saying it would be reconsidering the guidance. The court rejected EPA’s request, but the agency reissued the guidance anyway. In a Dec. 30, 2009, letter to engine manufacturers, Karl Simon, director of compliance and innovative strategies at EPA’s Office of Transportation and Air Quality, explained the revision as clarification in a misunderstanding of the intent of the guidance.

“Because some prescriptive language in CISD-09-04 may have led to confusion regarding our intent that the document be used as guidance, rather than setting forth binding requirements, I believe it is appropriate to provide a new document providing revised guidance regarding certification of heavy-duty diesel engines using SCR,” Simon said.

In a supplemental brief filed last month, Navistar said that if the new guidance supercedes the old, “the result is nevertheless the same.” The truck maker contends that the new guidance merely renames the previous “certification requirements” as “possible approaches” and substitutes the words “reasonably short” mileage for the specific mileage during which no NOx control is required. Navistar argues the new guidance remains a legislative rule because it relaxes the 0.2 gram NOx standard and establishes a new SCR-specific emissions standard.

EPA has until March 11 to respond to Navistar’s claims. Final briefs in the case are due April 9. While continuing to pursue its litigation against EPA over the February and December 2009 guidance, Navistar also is suing the agency over its November 2009 approval of scheduled maintenance intervals for SCR technology.