A postman drives a United States Postal Service mail delivery truck through Washington, DC, on August 13, 2021.
CNN  — 

The US Postal Service is moving ahead with a plan to replace its current fleet with 90% gas-powered trucks and 10% battery electric vehicles, after the Environmental Protection Agency and White House objected to the move and asked for further study of the impact of emissions.

Postmaster General Louis DeJoy reiterated that the Postal Service currently doesn’t have the funding available to increase the number of electric vehicles in its fleet.

“As we have reiterated throughout this process, our commitment to an electric fleet remains ambitious given the pressing vehicle and safety needs of our aging fleet as well as our fragile financial condition,” DeJoy, who was selected for the Postmaster General role during the Trump administration, said in a statement. “The process needs to keep moving forward.”

In a letter sent earlier this month, EPA associate administrator Vicki Arroyo said the USPS plan was “inconsistent” with clean-energy policies at state, federal and international levels, and called it a “crucial lost opportunity to more rapidly reduce the carbon footprint of one of the largest government fleets in the world.”

Brenda Mallory, chair of the White House Council of Environmental Quality, penned a separate letter urging USPS to improve its environmental review in accordance with the National Environmental Policy Act and adding that the agency could face repercussions from Congress or the courts if it failed to do so.

Despite their objections, the EPA and the White House can’t stop the USPS plan from happening; the USPS is an independent agency responsible for funding itself.

In a statement, Mark Guilfoil, vice president for supply management at USPS, said the agency “determined that EPA’s request for a supplemental [environmental impact statement] and public hearing would not add value to the Postal Service’s already year-long review,” adding that neither were legally required.

USPS said it will leave some flexibility to increase the number of EVs in the fleet “as financial resources become available.”

Adrian Martinez, a senior attorney at the environmental law group Earthjustice, said environmental groups would pursue litigation to get USPS to reverse course.

“DeJoy’s environmental review is rickety, founded on suspect calculations, and fails to meet the standards of the law,” Martinez said. “We’re not done fighting this reckless decision.”

CORRECTION: This story has been updated to correct DeJoy’s connection to Trump. He was selected by the USPS Board of Governors for the Postmaster General role during the Trump administration.