<p>Manson Construction Company required modification of permit to operate engines on a suction dredge within the Ventura County Air Pollution Control District (VCAPCD). The original engines on the dredge were older Tier 0 Off-Road diesel engines which were controlled with Selective Catalytic Reduction (SCR) systems to reduce emissions of nitrogen oxides (NOx) and carbon monoxide (CO). The replacement engines were considerably larger than their predecessors and were certified to United States Environmental Protection Agency (U.S. EPA) and California Air Resources Board (CARB) Off-Road Tier 2 standards. Because the new engines were not controlled with SCR, the project involved negotiations with VCAPCD to assure that the time-sensitive implementation could proceed without delay. Documentation related to the greater efficiency of the new engines and the fuel consumption necessary for completion were provided to VCAPCD. Also, emission calculations comparing the previous engines to the new engines were prepared to support the application. During the application review process the client agreed to provide for future control of diesel particulate, a regulated air toxic in California, through the use of Verified Diesel Emission Control Strategies (VDECS). The application involved producing the appropriate forms, emissions calculations, and supporting documentation. The additional information and negotiations resulted in permits being issued on time. The modification to permit in County of Ventura was completed, allowing the dredge to proceed to an additional permit in County of San Diego which involved a similar regulatory process.</p>