Operational changes implemented at the United States Postal Service are posing potentially “serious health risks” to Americans who rely on prescription drug deliveries, according to a new report from Sens. Elizabeth Warren (D-Mass.) and Bob Casey (D-Pa.).

The 10-page report looking into how changes at the Postal Service have impacted mail-order prescription deliveries, released on Wednesday, found that Americans may have seen “significant” delays in the delivery of prescription drugs in recent months.

In addition to the health risks, the delays in service could increase costs for consumers and the federal government, the senators wrote. The Washington Post first reported on the findings of their probe. 

The findings come as Postmaster General Louis DeJoy faces persistent scrutiny from Democrats over the operational and organizational changes he imposed after being appointed to the post in May. New policies reducing overtime and removing some mail-sorting machines helped cause delays in service nationwide.

“We know that Louis DeJoy is sabotaging the Postal Service, and our report is more evidence that his tenure has been a failure,”  Warren said in a statement. “He needs to resign — and if he won’t, the Board of Governors must remove him.”

The Postal Service did not immediately return a request for comment from The Hill. 

Warren said she and Casey began asking pharmacies about mail-order delivery problems in mid-August. The senators wrote to five of the largest pharmacies and pharmacy benefit managers and received indications from the majority of them that delays were “significant” and “increasing.” The companies who were contacted included Walgreens Boots Alliance, CVS Health, Humana, United Health and Cigna.

According to the report, mail-order pharmacies reliant on the Postal Service have reported between an 18 and 32 percent increase in delivery times for mail-order drugs in recent months. Deliveries that generally take between two and three days were instead taking three to four days.

One unnamed company said it saw a “marked increase in July in the number of patients experiencing shipment delays of seven days or more.” Only one respondent said it did not see any unusual delays in deliveries, though the company noted it is more reliant on private-sector carriers than the Postal Service.

The report indicates that some of the delivery service delays were being experienced before DeJoy took over as the head of the Postal Service. But it also included several examples from companies regarding an increase in consumer inquiries and shipment delays in July and August. They note the delays are made more problematic by the coronavirus pandemic and an increased reliance on mail-order prescription drug deliveries. 

Mail-order prescriptions grew by 21 percent in March when compared to the same time period in 2019, the senators wrote. 

Warren and Casey zeroed in on public testimony from DeJoy in which he said that the new changes at Postal Service should not have "impacted anybody," arguing they've instead put "the health of Americans in danger."

DeJoy's short tenure leading the Postal Service has been marked by criticism from Democrats and other state officials, who have voiced fears about whether changes at the agency are leaving it poorly equipped to handle a rise in mail-in ballots in this year's election. 

The House last month passed legislation that would prevent the Postal Service from carrying out the operational changes, but it is unlikely to be approved by the Senate. 

The House Energy and Commerce Committee last month also launched a probe into how the Postal Service changes were affecting prescription drug deliveries. The committee's leadership said at the time they would be contacting online pharmacies, pharmacy benefit managers and the relevant trade associations.