On May 11, the U.S. Environmental Protection Agency unleashed a new clean-air rule that further cuts diesel emissions from off-road vehicles, generators, locomotives and marine vessels. The new “Tier 4” mandate is EPA’s fourth step since introducing off-road standards in 1996, and it lowers such pollution by 90% (ENR 6/23/03 p. 13).

The rule varies across engine sizes, but most producers will reduce nitrogen-oxide levels in new engines to 0.3 grams per brake-horsepower-hour and particulates to 0.01 g/bhp-hr by 2014. Under the new rule, EPA is not requiring pollution controls on existing machines in the field.

advertisement ...

Off-road fuel also is discussed. Refiners will need to lower previously-unregulated sulfur content in off-road fuel to 500 ppm by 2007, and again to 15 ppm by 2010. Industry observers say this sulfur requirement is feasible, but it will require capital investment, including control-equipment retrofits, on some existing plants.

According to EPA, the entire move, which helps to align air-quality standards for on-road and off-road machinery, will cost producers and consumers about $2 billion annually. But the agency says the “enormous” benefits will prevent thousands of premature deaths, including an estimated total of $805 billion in public-health costs over the next 30 years.