Oregon’s attempts to curtail diesel emissions are in jeopardy following a state decision to delay enforcement of the Advanced Clean Trucks (ACT) rule until 2027. 

The ACT rule, which was approved by the Oregon Department of Environmental Quality (DEQ) Commission in 2021, seeks to reduce greenhouse gas emissions from high-polluting diesel engines by requiring truck manufacturers to sell a certain number of zero-emission electric vehicles each year. It went into effect at the beginning of this year, but faced significant pushback from truck manufacturers, who said they were unable to meet the requirements. 

The rules vary by truck size and capacity. For example, manufacturers are required to ensure electric vehicles make up a quarter of their heavy duty tractor truck sales by 2029. 

Earlier this year, two Republican state representatives introduced a bill that would prohibit the DEQ from implementing the ACT rule until 2027. The bill found bipartisan support in the Oregon House, but died in committee. Still, the effort to delay the rule found support elsewhere, including in Governor Tina Kotek’s office. In March, Kotek asked DEQ Director Leah Feldon to find a way to accommodate manufacturer concerns with the rule while “maintaining the integrity” of the policy for those who are able to comply. 

Now, the agency is delaying the rule requirements, which environmental advocates say will create problems well beyond 2027. The ACT was intended to help reduce Oregon’s greenhouse gas emissions from diesel pollution and improve public health outcomes. People exposed to diesel particulate matter are more likely to develop serious health problems, including cancer and cardiovascular issues.  

In a May 15 DEQ memo, Feldon wrote that although the agency attempted to amend the ACT to make compliance easier for manufacturers, the state was in a tough position and had to act fast. Feldon said this is in part due to uncertainty on the federal level, as the Trump administration aims to roll back investments in electric vehicle charging infrastructure and incentives to purchase zero-emission cars. Federal action on tariffs has also created chaos in the manufacturing industry, and Congress is considering action to entirely override state regulations like the ACT rule. 

Feldon also wrote that the delay was necessary because some manufacturers—notably, the Portland-based Daimler Truck company—have decided to limit all truck sales in order to meet ACT standards, in an act of protest against the rule. 

“The new truck market dynamics in Oregon are not functioning properly. In particular, the preferred compliance strategy of manufacturers not delivering internal combustion engine trucks to Oregon’s market to avoid accruing any deficits is failing to meet the needs of dealers and fleets,” Feldon wrote. “The current lack of available vehicles, as well as federal activities that threaten incentives and investments, are creating more urgency than the current rulemaking timeline can accommodate.” 

Kotek also blamed the feds for the delay, saying the Trump administration isn’t delivering obligated funds that would make it easier to develop electric truck charging infrastructure, among other investments. 

To ACT supporters, this looks like capitulation to the trucking industry. 

“With federal rollbacks already threatening climate progress, Oregon must stand firm—not retreat. Truck manufacturers and Big Oil have spent months spreading disinformation to fabricate a crisis, and unfortunately, some Oregon leaders are now echoing their talking points,” Lindsey Scholten, executive director of the Oregon League of Conservation Voters, said in a press release. “This is a massive step backward that harms Oregonians and puts polluter profits over public health.” 

According to Feldon’s memo, manufacturers will be exempt from ACT rule enforcement as long as they don’t limit their internal combustion engine vehicle supply, as Daimler said it would do late last year. Manufacturers also must put up “good faith efforts” to comply with the rule, and continue to submit sales reports to the DEQ to “ensure transparency and facilitate future assessments.” 

Truck manufacturers who griped about the rule claimed it’s unreasonable to expect compliance given the state of the electric truck market. During a January legislative hearing on the subject, a representative from Daimler said while the company is ready to meet electric truck demand, “the demand isn’t there today.” They cite a lack of charging infrastructure and the high cost of manufacturing electric trucks as primary impediments. 

But not all electric trucks would require specialized, public charging infrastructure. The majority of trucks sold in Oregon belong to the medium-duty class, which can be charged using standard electric car infrastructure. And manufacturers who specialize in making those trucks—like the electric car brand Rivian—support the ACT rule and say its delay will punish their companies. However, the DEQ can’t change its requirements for heavy duty trucks alone, as states are mandated by the Clean Air Act to align exactly with California’s adopted standards. 

 

While the DEQ says the delay is just that—a temporary pause—critics of the decision are skeptical. The pause in enforcement is confusing to the market and reduces demand for investments in charging infrastructure, making manufacturers’ current problems worse. Many environmental advocates have believed “delaying the ACT is setting the stage to kill it” permanently, as Mary Peveto from Neighbors for Clean Air said about the DEQ’s decision. 

“Delaying Oregon’s clean truck rules is not just a policy decision - it’s a public health failure. Diesel pollution is a proven threat to heart and lung health, particularly for children, seniors, and communities living near highways and freight corridors,” Peveto said. “The oil and gas lobby and national truck manufacturers are exploiting this moment of federal overreach to push their agenda in Oregon. And unfortunately, some state leaders appear ready to go along with it.” 

Feldon’s memo said the DEQ director “may revise or rescind [the delay] in the event that the exceptional circumstances no longer exist or other unforeseen and relevant factors have changed.” 

Brett Morgan, transportation policy director at Climate Solutions, said state legislators could help create the environment for the DEQ to retract its decision through its major transportation package, which is currently in development. 

“The transportation package can allow Oregon to enact solutions to the problems they espouse on ACT, but to solve problems we need action and funding for these key programs, not complaints,” Morgan said. “Legislators still have the chance to be the heroes here.”