The heads of major pharmaceutical distributors testified during a hearing on Capitol Hill about their companies’ roles in the opioid epidemic currently sweeping the nation. The pharmaceutical distributors are accused of flooding small U.S. towns with prescription painkillers. “We want to know what these companies knew about the rise of the opioid epidemic, when they knew it, and if it informed their distribution practices,” said Rep. Diana DeGette (D-Colo.)

A House Energy and Commerce Committee oversight panel has spent the past year investigating pill dumping in West Virginia. West Virginia has the nation’s highest rate of opioid overdose death. A single pharmacy in Kermit, W. Va., a town of about 400 people, received nearly 9 million hydrocodone pills over two years.

One company executive apologized for not doing more to stop millions of powerful prescription opioids from being shipped to pharmacies in two small West Virginia towns. Cardinal Health, along with McKesson Corp. shipped 12.3 million doses of prescription opioids to the Family Discount Pharmacy in Mount Gay-Shamrock, W.Va. from 2006 to 2014. The Hurley Drug Company in Williamson, W.Va. received more than 10.5 million pills from Cardinal Health during that same time period.

Cardinal said it has not sent the drugs to Mt. Gay-Shamrock since 2012 and to Williamson since 2014. Cardinal Health Executive Chairman George Barrett said, “With the benefit of hindsight, I wish we had moved faster and asked a different set of questions. I am deeply sorry we did not. Today, I am confident we would reach different conclusions about those two pharmacies.”

Only one of the industry leaders admitted that his company contributed to the nation’s opioid crisis. Joseph Mastandrea said during the hearing that he believes his company, Miami-Luken, contributed to the opioid crisis. The other companies involved in the hearing said they do not believe their companies contributed to the crisis.

In their arguments, the companies say that distributors are not responsible for overprescribing medications because only fulfill orders from pharmacies. They also claimed that opioid painkillers account for only a small portion of their overall business. McKesson chief executive John Hammergren said the company distributed about 151 million doses of oxycodone and hydrocodone in West Virginia between 2007 and 2012. For all prescription medicines, McKesson distributed nearly 2 billion doses in the state during that time frame.