Intermountain Healthcare will pay the federal government $1 million to settle allegations that a lack of oversight allowed a former employee to divert tens of thousands of pills for personal use, officials announced Friday.

It is thought to be the largest settlement related to drug diversion in Utah history, the U.S. attorney’s office said in a statement. Court documents were never filed in the case, which was investigated by the U.S. Drug Enforcement Administration (DEA), a U.S. attorney’s office spokeswoman said.

“Under the law, healthcare networks such as IHC have a responsibility to ensure that controlled substances are used for patient care and are not diverted for non-medical purposes,” U.S. Attorney John Huber said in the statement, adding that such drug diversion “fuels the opioids epidemic” in Utah.

As part of the settlement, Intermountain agreed to a “comprehensive corrective action plan” to prevent future drug diversions, according to the statement. An Intermountain spokesman, Daron Cowley, said new oversight and control systems have been implemented, but he declined to explain what those changes entail.

“This settlement resolves an issue that occurred at one clinic [North Ogden Clinic] stemming from illegal behavior of one former employee who perpetrated a sophisticated drug diversion scheme starting in 2007,” Cowley said in an emailed statement. “When the scheme was brought to light, we fully cooperated with authorities, and the employee was terminated and criminally prosecuted.”

From 2007 to 2015, federal authorities say, a former medical assistant at North Ogden Clinic allegedly used a DEA doctor’s registration number to issue prescriptions to herself and two family members — including opioid pain-relief medications, anti-anxiety medicine and a weight-loss drug. The clinic’s pharmacy filled the prescriptions for the medical assistant, whom the company and the attorney’s office did not identify.