A truck leaves the U.S. Postal Service's sorting facility in Scarborough in this 2015 file photo. Credit: Troy R. Bennett / BDN

Tens of thousands of pieces of mail were delayed in getting to Mainers in more than a dozen towns Monday amid a policy shift within the U.S. Postal Service.

The Portland Press Herald reports that as much as 80,400 letters and other pieces of mail were left behind at the Postal Service’s Scarborough distribution center on Monday because a new policy prohibits any late trips.

A union president told the Portland newspaper that the mail was already sorted and just needed to be loaded onto trucks. But rather than wait 10 minutes, they left without the mail.

The Scarborough distribution center processes about 1 millions pieces of mail on Sunday nights, according to the Press Herald.

A Postal Service spokesperson disputed that account, telling the Press Herald that the mail wasn’t held until Tuesday but shipped out on the next scheduled run to the 10 affected Post Offices.

That news comes after Postmaster General Louis DeJoy issued new rules to postal workers that prohibit late or extra trips.

“If the plants run late, they will keep the mail for the next day,” according to a memo obtained by the Washington Post. In another document circulated among postal ranks, postal workers were told it may be “difficult” to see mail left behind, but that “We will address root causes of these delays and adjust the very next day,” the Washington Post reports.

The memo stated the policy change was to reduce transportation costs, saying that extra and late trips cost the agency $200 million a year.

The Postal Service has come under added strain during the coronavirus pandemic as first-class mail volumes declined 15 percent to 20 percent in April and May, while marketing mail took a steeper hit, with 30 percent to 50 percent declines over the same period, according to the Washington Post.

But the Postal Service also has seen a jump in package deliveries — 60 percent to 80 percent — as most of the nation sheltered at home during the early weeks of the coronavirus pandemic, which helped to offset those other losses, according to the Washington Post.

Just last month, Portland’s postmaster, James Thurston, was accused of intentionally delaying the delivery of mail in favor of prioritizing the delivery of Amazon packages ― a possible violation of federal law.