Navistar Points to CARB Research to Back Up Claims Against SCR

Navistar, the parent company of IC Bus, has taken its fight against selective catalyst reduction and for advanced exhaust gas recirculation as the right choice for meeting upcoming EPA 2010 emissions requirements in lowering nitrogen oxide (NOx) emissions at the tailpipe to no more than 0.2 grams. Currently, Navistar is suing the EPA in federal appeals court as it contends the feds by allowing SCR in its regulations will being increasing public health risks due to urea, the additive used in SCR to reduce NOx in the engine that has been used for the past two decades in Europe.

The aggressive marketing performed by Navistar this year has drawn criticism from many in automotive and fleet circles, such as Oliver Dixon's "Spiral of Dispair" article earlier this week on The World Trucks Blog at UK's But then, Navistar offered a rebuttal by claiming that a June letter penned by Bart Croes, chief of California Air Resources Board research, to the Health Effects Institute, a Boston nonprofit organization planning tests on 2010 engines, that said that the use of SCR represents a "large departure from conventional emission controls by introducing a liquid additive containing an organic form of nitrogen." According to, The letter goes on:
“Some toxic air contaminants that have been identified with SCR technology include hydrogen cyanide, cyanic acid, nitromethane, hydrazine, acrylonitrile, acrylamide, acetonitrile, and acetamide,” Croes wrote in his letter. “It is hoped that any exotic substances emitted from SCR technology will be at levels insignificant to exposure health effects.”

Although we are encouraged by findings to date, which suggest that the technology can deliver significant reductions of many species of toxicological relevance, this work has also documented the increase in some emissions such as some metals, nitrous oxide and nanoparticles.”
In the August issue of School Transportation News, contributor Bob Pudlewski writes that fleets must individually decide which technology best suits their needs, but either one has an increased price tag.

The debate rages on.
Last modified onFriday, 25 April 2014 05:42