An alarming 66,000 people died in the U.S. in 2016 from opiate drug overdoses. That number of fatalities is higher than the death tolls in the worst years for HIV/AIDS, gun violence and the Vietnam war.

Those alarming numbers were part of a presentation on opioid addiction given by Robert Pennal, former task force commander of the Central Valley High Intensity Drug Traffic Area (HIDTA).

Opiates are substances that act on brain receptors to release chemicals that produce euphoria and pain relief. They can be highly addictive. Pennal’s presentation at Fresno State last week detailed the rampant abuse of opiates in the U.S. and California.

He said the abuse of these substances is the single greatest drug epidemic in the history of the U.S.

“We have never seen anything like this in America,” he said.

To illustrate the concerns, Pennal turned to news clips that shed light on the opiate crisis. He showed a clip from “60 Minutes” that documented how the pharmaceutical industry has pushed doctors to overprescribe painkillers to patients, leading to the addiction.

“The pharmaceutical companies are so powerful and have so much money. It’s all about making money,” Pennal said. “This world of synthetics is a nightmare, and we are not sure what we are going to do about it.”

Pennal said some experts estimate heroin made from poppy plants will not exist in five years because most of the drugs being abused are becoming synthetic.

And although OxyContin has become the most commonly abused prescription pain medication in the country, the most powerful medications include Fentanyl and Carfentanil, Pennal said.

Fentanyl is an opioid that is 50 times more powerful than heroin. Carfentanil is 50 to 100 times more powerful than Fentanyl, Pennal said.

Carfentanil is especially dangerous, Pennal explained, because it is not made for humans — rather, it is a tranquilizer made for large animals typically found in zoos, like elephants.

And when people overdose on Carfentanil, it is difficult to revive them because of the potency of the drug.

“We’re talking about amounts as little as grains of salt that can kill you,” Pennal said.

Pennal pointed to the Mexican and Chinese drug cartels as sources that have brought the drugs into the U.S. and led to purchase by American consumers.

The drugs are mostly bought on what is called the Dark Web, the seedy underbelly of the internet in which most illegal and illicit business activities take place.

The Dark Web is so widely used for criminal activities because it offers anonymity through Virtual Private Networks (VPNs), which bounce a computer’s internet provider address through dozens of networks across the globe — making it impossible for law enforcement agencies to trace the original computer’s location.

“Once a drug is purchased through the Dark Web, it is typically shipped from Mexico in commercial trucks to disguise what is being transported,” Pennal said.