Reference No. Z-99-138
MSC 99-29



This correspondence is to invite you to comment on the draft amendments to the regulations for off-road compression-ignition (diesel) engines and equipment.

In 1994, the Air Resources Board (ARB) approved a State Implementation Plan (SIP) for ozone. The SIP contains measure M9, which calls for new state and national emission standards for off-road diesel engines. In September 1996, ARB, the United States Environmental Protection Agency (U.S. EPA), and the diesel engine manufacturers signed a statement of principles (SOP) calling for harmonization of ARB and U.S. EPA off-road compression-ignition engine regulations. The SOP is a cooperative agreement between ARB, U.S. EPA, and the engine manufacturers that recognizes the technological feasibility of significant emission reductions from off-road compression-ignition engines. In August 1998, U.S. EPA adopted new emission standards, along with changes to the existing federal averaging, banking, and trading program, and changes to useful life and maintenance requirements for off-road diesel engines. The draft amendments to existing California emission standards and test procedures are designed to harmonize as closely as possible with the federal program, while still maintaining the emission reduction benefits of the current California program.

Staff's draft proposal includes the following major revisions to the regulations: 1) new reduced-emission standards for particulate matter, carbon monoxide, and non-methane hydrocarbons and oxides of nitrogen combined which vary by horsepower and implementation date; 2) these standards will be based on new useful life, warranty, maintenance, and rebuild provisions; 3) engine manufacturers may elect to participate in the averaging, banking, and trading program; 4) voluntary emission standards will be available to engine manufacturers through the 2004 model year for additional emissions benefit; 5) implementation flexibility will be provided for equipment and vehicle manufacturers and post-manufacture marinizers.

The coordinated efforts of ARB, U.S. EPA, and the engine manufacturers to introduce lower-emission off-road vehicles and equipment nationwide will result in substantial air quality benefits in California and the rest of the country.

We are hoping to present our proposal to the Board for consideration at the December 9-10, 1999 public hearing. We look forward to your participation and hope to respond to your comments prior to publication of the draft amendments to the regulations. Please submit comments in writing, no later than October 25, 1999, to Ms. Jackie Lourenco, Manager, Air Resources Board, Off-Road Controls Section, 9528 Telstar Avenue, El Monte, CA 91731-2988.

If you have any questions regarding this mailout, please contact Ms. Jackie Lourenco, Manager, Off-Road Controls Section, at (626) 575-6676, or Andrew Spencer at (626) 575-6675.



Robert H. Cross, Chief
Mobile Source Control Division


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