This legislation, known as the Diesel Emissions Reduction Act of 2025 , is designed to continue the important work of reducing harmful emissions from diesel engines nationwide. It achieves this by reauthorizing the Diesel Emissions Reduction Program (DERA) , which provides financial assistance for projects aimed at upgrading or replacing older, higher-emitting diesel engines. The bill specifically amends Section 797(a) of the Energy Policy Act of 2005. This amendment extends the program's authorization period by changing its expiration date from 2024 to 2029 , thereby ensuring its continued operation and funding for an additional five years to support environmental and public health improvements.