The U.S. Department of Justice announced a lawsuit today accusing pharmacy chain CVS of filling illegal opioid prescriptions and billing federal health insurance programs, contributing to a nationwide epidemic of opioid addiction and overdose.

The newly unsealed complaint in Providence, Rhode Island federal court alleges that, from October 2013 to the present, CVS violated the federal Controlled Substances Act by filling prescriptions for dangerous quantities of opioids and dangerous combinations of drugs.

It said the company regularly filled prescriptions from doctors running so-called pill mills, dispensing large quantities of opioids without legitimate medical reason.

The Justice Department said the violations were driven by company-mandated performance metrics that led to red flags being ignored, and that in some cases patients died of overdoses shortly after filling illegal prescriptions.

“We have cooperated with the DOJ’s investigation for more than four years, and we strongly disagree with the allegations and false narrative within this complaint,” CVS said in a statement. CVS agreed in 2022 to pay close to $5 billion over 10 years to settle thousands of similar claims by state, local and Native American tribal governments. It did not admit wrongdoing under the deal, which was one of a series of nationwide settlements by pharmacies, drugmakers and distributors totaling about $46 billion.

The Justice Department’s lawsuit unsealed on Wednesday began as a whistleblower complaint brought by a former CVS employee.

According to the lawsuit, CVS maintained inadequate staffing and pushed its pharmacists to fill prescriptions as quickly as possible without investigating whether they were legitimate, and ignored warnings from its own employees.

“Safety issues arise when one is dealing with medication and also being rushed to fulfill an order like McDonald’s,” one employee allegedly wrote. “CVS has concocted an assembly-line style of medication preparation and only cares about profits.”

The company continued to fill hundreds of prescriptions for one Alabama doctor even after multiple internal notes warned in 2015 that he was under investigation, the complaint said. That doctor was arrested in 2016.

It filled thousands of prescriptions for a Pennsylvania doctor despite internal warnings and online patient reviews saying he “writes scripts without seeing the patient” and is “a pill pusher, and a drunk,” the Justice Department said.

The complaint described 10 individual patients who died, allegedly after filling illegal prescriptions for opioids and other drugs at CVS. More than 800,000 people in the United States died of opioid overdoses from 1999 through 2023, according to data from the U.S. Centers for Disease Control and Prevention. Preliminary data shows overdoses began to decrease last year.