A deadly drug that is 5,000 times more potent than heroin has been appearing in Casper, causing the near-deaths of at three people this week alone. That's according to Casper Police Chief Keith McPheeters, who says that some of the local drug users are coming into contact with carfentanil.

According to the U.S. Drug Enforcement Administration, carfentanil is a synthetic opioid that is 10,000 times more potent than morphine, 5000 times more potent than heroin, and 100 times more potent than fentanyl. It's classified as a Schedule II substance under the Controlled Substances Act and is used as a tranquilizing agent for elephants and other large mammals.

"it's so powerful and so strong that our local addicts or the people who would be given to using that type of drugs, they're not used to it and so we've had three near death experiences here this week alone, " says Chief McPheeters.

He says it's a completely different substance. "They may not be aware of what they've purchased, it could be completely something they're not expecting and it's so strong it will cease their breathing almost immediately."

It's not only extremely dangerous to the user, but the DEA says carfentanil and other fentanyl-related compounds are a serious danger to public safety, first responders, and medical, treatment, and laboratory personnel. These substances can come in several forms, including powder, tablets, blotter paper, and spray, and they can be absorbed through the skin or by accidentally inhaling airborne powder.

The Department of Health and Human Services last year declared the "opioid epidemic" to be a public health emergency.