The opioid epidemic sweeping America has become a hot-button political issue in the U.S. Senate race between Marsha Blackburn and Phil Bredesen.

Now, a former top investigator for the U.S. Drug Enforcement Administration is taking sides.

Jim Geldhof recently recorded a television ad for the Bredesen campaign in which he accuses Blackburn of introducing legislation in the middle of the opioid crisis "that's going to make it more difficult for DEA to do their job."

The Williamson County Republican has said that putting handcuffs on the DEA's enforcement ability was "an unintended consequence" of her legislation.

"I can assure you there were no unintended consequences by the industry -- they got exactly what they wanted," Geldhof said in an exclusive interview with NewsChannel 5 Investigates.

For more than 40 years, Geldhof was on the front lines of the DEA's battle against illegal drugs.

As an investigator, he watched as a the drug Oxycontin created a new generation of addicts in the 90s. He was stunned by the dramatic rise in internet pharmacies, followed by a sharp uptick in pain clinics across the country.

"When I saw the amount of pills that the legitimate industry was shipping to these doctors and pharmacies, it was outrageous," Geldhof said. "That's when I was, like, this can't go on."

Our NewsChannel 5 investigations have revealed how users from across the country would flock to clinics that seemingly popped up overnight.

"Some of these pharmacies were going through seven or eight million hydrocodone within a year - and that's just the hydrocodone, not including the Xanax or the Valium," the retired investigator said.

"So the numbers were off the charts."

Geldhof's job was to try to stem the flood of opioids to questionable operators.

Yet, he insisted the pharmaceutical industry itself knew exactly what was going on.

"They knew where these drugs were going, they knew the quantities they were going into, and it was all about bucks -- it's as simple as that."

Last year, a "60 Minutes" investigation profiled efforts by the pharmaceutical industry to pass a bill in 2016 that was touted as a way to help patients.

It also made it more difficult for the DEA to go after distributors involved in shady shipments of opioids.

Blackburn co-sponsored the legislation.

NewsChannel 5 Investigates asked Geldhof, "Surely, you're not suggesting that members of Congress intended for this to happen, are you?"

"I don't know what's worse," he answered, "whether they intended it to happen or they passed legislation and they don't even know what they are passing."

In a recent debate with Bredesen, Blackburn insisted that "the opioid epidemic is one that affects everybody."

She argued that "the bill was voted on and passed unanimously in both the House and the Senate."

We checked, and Blackburn's right.

The DEA ultimately signed off on the bill. It passed Congress with no debate, and a Democratic president signed it into law.

NewsChannel 5 Investigates noted to Geldhof, "Democrats went along with it. President Obama signed it into law. Is it fair to blame one person?"

"I blame them all," he answered, quickly adding: "She sponsored the legislation."

In response, Blackburn campaign spokesperson Abbi Sigler accused Bredesen's team of politicizing a public health crisis.

Here is her statement: