California extends CARB diesel requirements to locomotive and marine engines

19 November 2004

The California Air Resources Board (ARB) amended yesterday California diesel fuel regulations by extending the applicability of CARB diesel to intrastate railroad locomotives and marine engines effective January 2007. Within the South Coast Air Quality Management District (Southern California including Los Angeles), CARB diesel must be sold for marine engines effective January 2006.

Since sulfur in CARB diesel is limited to 15 ppm from June 2006, ultra-low sulfur diesel (ULSD) will be mandatory for locomotive and marine engines in California from 2007, years ahead of federal requirements. The US Environmental Protection Agency (EPA) regulated ULSD for locomotive and marine engines effective June 2012.

Since California has no authority to regulate interstate commerce, the new CARB diesel requirements apply only to locomotives or marine engines operating within California. Intrastate locomotives are defined as those that spend at least 90% of their time in California.

California introduced more stringent diesel fuel standards, which differed from federal specifications, in 1993. The fuel, known as the “CARB diesel”, had the same sulfur cap as federal highway diesel, but a more stringent 10% aromatics limit. At the time of its introduction, CARB diesel was mandatory for both on- and off-road vehicles with the exception of stationary engines, locomotives, and marine vessels.

The new fuel requirements were supported by most stakeholders, including fuel refiners, railroads and environmental organizations.

Source: ARB (diesel fuel page)