So deadly a touch can kill: What is fentanyl?

KNOXVILLE, Tenn. (WVLT) -- While drugs like methemphetamine have upended families and destroyed lives around the state, the Tennessee Bureau of Investigation said agents have been forced to eye a new substance that has silently made its deadly debut: fentanyl.

So, what exactly is it?

Law enforcement officers in Tennessee fixed their focus on heroin after they began seeing an increase in the drug's presence across the state. However, the influx of heroin has given rise to an even bigger problem concerning what the drug could be laced with.

Law enforcement agencies have increasingly seen heroin laced with fentanyl, according to the TBI. Fentanyl was defined as a synthetic opioid that is used for severe pain and is exponentially more potent than heroin. Officials said fentanyl in its purest form is so deadly, just absorbing it through the skin can be fatal. Those who have overdosed on fentanyl could experience symptoms that range from breathing problems to death.

However, drug users haven't been the only people affected by the dangers of the substance. Law enforcement professionals have also been victims. In Tennessee, TBI crime labs have received several samples of heroin laced with fentanyl, as well as pure fentanyl packaged as heroin.

In 2014, the TBI was forced to launch a program that would provide handheld auto-injectors to agents and forensic scientists in the labs that may come into contact with the substance.

The new drug has been the cause behind dangerous situations faced by law enforcement in the field. For example, agents recently recovered what looked like oxycodone pills during a traffic stop, with the same size, appearance and stamp of oxycodone. However, lab analysis found the pills were counterfeit and actually contained fentanyl.

If you encounter a substance that could contain fentanyl, do not attempt to touch or move it. Call law enforcement so officials who have received specialized training and are able to analyze and dispose of the substance in the safest manner possible.

For more information about the drug, including a fact sheet, the threat to law enforcement and trade names, visit the U.S. Drug Enforcement Agency website.