The Health Department in conjunction with Cargill Inc. has provided for the retrofitting of Shelby County School buses. So far 70 school buses have been retrofitted with a Closed Crank Case Ventilation System (CCV) and Diesel Particulate Filter (DPF). The filters reduce particulate pollution up to 70% and the CCV totally eliminates emissions from inside the bus, thus keeping fumes away from the students. Before summer break, all 100+ buses will be retrofitted. The CCV also keeps oil off the ground and out of the air as exhaust by recirculating it to the engine where it is re-burned. Other equipment purchased with the funds from Cargill is the DPF Thermal Processing Unit (used to clean the filter so it is usable again) and the DPF Cleaning System which vacuums the filter (this equipment can also be used for the old style as well).