S. 747 would authorize the appropriation of $100 million annually through 2024 for the Environmental Protection Agency (EPA) to provide grants and rebates for projects and state programs that reduce emissions from diesel engines. The bill also would require EPA to provide guidance to states about technical differences in vehicles, engines, equipment, and vehicle fleet use. Finally, the bill would direct that funds not allocated to state diesel programs be reallocated to projects for retrofitting vehicles. In 2019, $87 million was appropriated for those purposes.
Assuming appropriation of the specified amounts, CBO estimates that implementing the bill would cost $410 million over the 2020-2024 period and $90 million after 2024 (see attached table). The costs of the legislation fall within budget function 300 (natural resources and environment).