In August 2002, the SCAQMD’s Mobile Source Committee approved the “Health Risk Assessment Guidance for Analyzing Cancer Risks from Mobile Source Diesel Emissions.” This document provided guidance for analyzing cancer risks from diesel particulate matter from mobile sources at facilities such as truck stops and warehouse distribution centers. Subsequently, SCAQMD staff revised the aforementioned document to expand the analysis to provide technical guidance for analyzing cancer risks from potential diesel particulate emissions impacts from truck idling and movement (such as, but not limited to, truck stops, warehouse and distribution centers, or transit centers), ship hotelling at ports, and train idling. This revised guidance document titled, “Health Risk Assessment Guidance for Analyzing Cancer Risks from Mobile Source Diesel Idling Emissions for CEQA Air Quality Analysis” was presented to and approved by the SCAQMD’s Mobile Source Committee at its March 28, 2003 committee meeting. It is suggested that projects with diesel powered mobile sources use the following guidance document to quantify potential cancer risks from the diesel particulate emissions.