The letter comes ahead of the annual general meeting of Daimler Truck, the biggest truck manufacturer in the U.S. market, where it will face investor countermotions about competitive risk from the Tesla Semi and its role in pushing back regulations on electric trucks.

A court granted the EMA permission to intervene in the Endangerment Finding lawsuit, which Sierra Club, Public Citizen, Green Latinos and 16 other groups have slammed as “a poor business decision” in the letter.

The letter adds: “This repeal has already created regulatory whiplash and added uncertainty around future emissions standards, making it harder for manufacturers to plan investments, manage supply chains, and allocate capital with confidence.”

The groups call on the truck manufacturers to push the EMA to withdraw from the court case “or failing that, publicly distance themselves from EMA’s litigation efforts”. They add: “If EMA continues down its current path, we believe your companies should withdraw your membership.”

Daimler Truck, Volvo Group, other truck manufacturers and their lobby groups have taken several actions to stall or stop truck electrification, including a lawsuit against California over an agreement to advance zero emission trucking goals. But truck manufacturers risk ceding market share as new entrants including the Tesla Semi enter the market, beating existing models on price, range and charging speed. Last week Tesla announced it had began production of the Semi on a “high volume line”.

Juan Roberto Madrid, GreenLatinos Sustainable Communities Program Manager

“Latino truck drivers are already being crushed by diesel prices that have surged over 40% because of Trump’s Iran war — the largest oil supply disruption in history. Now EMA and Daimler want to pile on by intervening to gut the very clean truck standards that would reduce our dependence on that dirty, expensive diesel. This is a double betrayal of the Latino workers and communities who make this industry run. These companies are not protecting American workers — they are protecting their profit margins while our people choke on diesel exhaust and go broke at the pump. We will not stand by while our communities are used as sacrifice zones.”

Craig Segall, former Deputy Executive Officer and Assistant Chief Counsel of the California Air Resources Board

“The truck cartel just sided in court with Donald Trump to blow up climate progress. As diesel prices spike, truck makers feebly announced it is too hard to bring US drivers the same kinds of affordable electric trucks that are zooming down every port street in China — so they won’t try. If I had a single dollar invested in one of these companies, I’d demand the leadership be fired if they don’t disavow this anti-customer lawsuit.”

Katherine Garcia, Sierra Club’s Clean Transportation for All Campaign Director

“The Truck and Engine Manufacturers Association’s support of EPA’s repeal of life-saving clean truck standards is appalling. Truck manufacturers like Daimler and Volvo have slow-walked clean trucks for years and now want to throw them under the bus altogether, undermining American competitiveness and thumbing their nose at truck drivers and communities who demand the health and climate benefits of clean trucks. At a time when diesel is skyrocketing, truck manufacturers can no longer afford to cling to the past—they must invest in a cleaner, more resilient future and support the policies needed to accelerate truck electrification.”