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California’s top air quality agency today called on the Biden administration’s Environmental Protection Agency to “immediately” approve the state’s order to phase out diesel trucks.

Air Resources Board Chair Liane Randolph was one of more than 250 people registered for a virtual hearing today on whether the EPA should grant California a waiver allowing the state to implement its regulation. The hearing was scheduled to last 12 hours.

California’s law, passed in 2023, is the first in the world to ban new diesel trucks and require a shift to zero-emissions semi-trailers, garbage trucks, delivery trucks and other medium- and heavy-duty vehicles. Starting in 2036, no new medium- and heavy-duty fossil-fuel trucks will be allowed to be sold in the state. Large trucking companies must convert their fleets to electric or hydrogen models by 2042.

The diesel ban is one of the most far-reaching and controversial measures that California has adopted in recent years to reduce air pollution and greenhouse gases.

Trucking companies, agricultural groups and others told the EPA today that the rules would hurt the economy and the deadlines would be difficult to meet. Environmental and civic groups, clean energy companies and at least one major retailer, Ikea, spoke in favor of the measure.

For more than 50 years, California has had the authority under the Clean Air Act to set its own emissions standards for trucks, cars and other vehicles, but the EPA must grant a waiver for each individual rule California enacts before it can be implemented.

One of the state’s deadlines – regulating trucks operating in ports – was supposed to take effect this year, but the aviation agency has delayed implementation of the measure until it receives an exemption from the EPA.

An EPA spokesman declined to say when a decision on the exemption would be made.

The waiver request is one of several that California regulators hope the EPA will decide on before the November election. Supporters of California’s climate rules fear that a return of former President Donald Trump to the White House could block future approvals.

Randolph told the EPA that diesel trucks contribute “significantly” to the state’s air pollution and greenhouse gas emissions, so transitioning California’s fleets from diesel to electric or other zero-emission options is critical to improving public health and meeting the state’s climate goals.

Andrea Vidaurre, co-founder of the People’s Collective for Environmental Justice, a San Bernardino-based citizens’ group, says zero-emission trucks are needed to eliminate air pollution in the Inland Empire, where warehouses and trucking companies are located.

“This is the only way we can actually provide some relief to the communities that live in some of the … deadliest air pollution areas in the country,” she said. “We don’t see any other way.”

But trucking companies point out that zero-emissions semi-trucks can be twice as expensive as the diesel version, take hours to charge, don’t have the range many companies need and don’t have an adequate network of charging stations across the state.

Matt Schrap, executive director of the Harbor Trucking Association, which represents truck operators at California’s major ports, called the rule “unprecedented” and “ill-conceived.” The rule would hit truck drivers hard and would be impossible to implement, Schrap said, because the state does not have the charging network needed to meet demand for electric trucks.

“It’s not that anyone in our industry is against advanced technologies,” Schrap said. “But we are very concerned about how this regulation is implemented because it has real implications, not only for companies but also for the end consumer.”

Under the Clean Air Act, the EPA must follow certain rules when denying a California exemption: California’s decision would have to be “arbitrary and capricious” in its determination that its standards protect public health, or the state does not need the rules to “satisfy compelling and extraordinary conditions,” or they violate the Clean Air Act’s technical feasibility provisions.

For decades, the EPA has granted California waivers to set its own ambitious, technology-leading standards for cars, trucks and other fuels. Only one waiver was initially rejected – a 2008 rule setting greenhouse gas emissions limits for cars – and that decision was quickly reversed and the waiver approved.