WASHINGTON — A U.S. Postal Service plan to replace its huge fleet of mail-delivery trucks has too few electric vehicles and falls short of President Joe Biden’s goals to address climate change, the Environmental Protection Agency said.

In a sharply worded letter last week, the EPA said the Postal Service plan to make 10% of its next-generation fleet electric “underestimates greenhouse gas emissions, fails to consider more environmentally protective feasible alternatives and inadequately considers impacts on communities with environmental justice concerns.”

EPA called for a new environmental review, saying the current proposal is a “crucial lost opportunity to more rapidly reduce the carbon footprint of one of the largest government fleets in the world.”

The EPA also asked the Postal Service to hold a public hearing on the fleet modernization plan.

A 10% commitment to clean vehicles, “with virtually no fuel efficiency gains for the other 90%, is plainly inconsistent with” Biden’s plan to “move with deliberate speed toward clean, zero-emitting vehicles,” Associate EPA Administrator Vicki Arroyo wrote in a five-page letter.

A Postal Service spokeswoman said the agency was reviewing the EPA letter.

“While we can understand why some who are not responsible for the financial sustainability of the Postal Service might prefer that we acquire more electric vehicles, the law requires us to be self-sufficient” and consider costs, spokeswoman Kim Frum said.

“The Postal Service is certainly willing to accelerate the pace of electrification of our delivery fleet if a solution can be found to do so that is not financially detrimental” to the agency, she added.

In a document submitted to EPA, the Postal Service said full electrification of the 230,000-vehicle fleet would cost an additional $3.3 billion over the current plan. Money for a 100% EV fleet is included in Biden’s $2 trillion Build Back Better plan, but the proposal remains stalled in Congress because of objections by Republicans and Sen. Joe Manchin, D-W.Va.

Biden has set a goal to slash planet-warming greenhouse gas emissions by at least 50% below 2005 levels by 2030, with a goal to achieve net-zero emissions by 2050.

Postmaster General Louis DeJoy, a political ally of former President Donald Trump, oversaw the agency’s decision to award the contract to Wisconsin-based Oshkosh Defense. DeJoy, whose leadership of the mail service has come under fire because of delivery delays and other problems, told Congress last year that the agency could only afford to make 10% of the new fleet electric.

Brenda Mallory, chair of the White House Council on Environmental Quality, told DeJoy in a letter last week that she has “grave concerns” about the environmental review his agency conducted. As an independent agency, USPS is subject to the National Environmental Policy Act and could face legal recourse from Congress or the courts if it makes a decision that is not “grounded on sound legal footing,” Mallory said.

The EPA, in its letter, said the Postal Service plan to replace its fleet of mail trucks and other delivery vehicles represents “the single largest federal vehicle procurement in the foreseeable future.”

The postal fleet is likely to stay in service for decades, making the decision of how to replace it an “unparalleled opportunity for the federal government to lead by example on climate and clean energy innovation,” Arroyo wrote.

The Postal Service awarded Oshkosh Defense $482 million as an initial investment to assemble 50,000 to 165,000 Next Generation Delivery Vehicles. The company has said it will make the vehicles at a warehouse in South Carolina, creating 1,000 new jobs.

The new vehicle is greener than current models, which date to the 1990s, but most still will be powered by gasoline. The fleet will have climate control, air bags, backup cameras and collision avoidance. USPS described the deal as the first part of a 10-year effort to replace its fleet.