Under the Clean Air Act, states are generally preempted from adopting state emission standards for mobile source emissions, except that California is afforded a special exemption due to its unique air quality problems. Other states may elect to adopt the more stringent California vehicle emission standards, rather than rely on the federal standards. If a state adopts California’s emissions standards, they must do so identically.
Delaware is one of the states that has adopted the California standards, see 7 Del. Admin. C. 1140, but it has not yet adopted California’s zero-emission vehicle standards, known as “Advanced Clean Car II,” which seek to restrict and later ban the sale of most new vehicles powered by gasoline and diesel. In March 2022, Governor Carney directed DNREC to begin the process of adopting the Advanced Clean Car II standards.
In November and December 2022, DNREC received public input and comment regarding the adoption of these standards, including holding several public workshops. Under these regulations, the sale of traditionally fueled light-duty passenger cars, trucks, and SUVs would be rapidly scaled down in Delaware starting in late 2025, culminating with a total ban on the sale of new gasoline and diesel-powered vehicles by model year 2035. Once the proposed regulatory language is finalized, DNREC will promulgate the draft proposed regulatory language and hold a public hearing, likely in early 2023. DNREC expects that the Secretary’s decision/order regarding the adoption of the new regulations will be issued in mid-2023.