It's one of the most powerful painkillers on the market, now being made illicitly and sold on the streets.
"It's potency is so much greater than anything we have out there," said Kathleen Rebbert-Franklin, Deputy Director of Population-Based Behavioral Health for the State.
The synthetic opioid is flooding the area, but it's being cut with, and marketed as other drugs.
"You have no idea what you're getting when you take that and snort it or inject it," Captain Lee Dunbar with the Harford County Narcotics Task Force said.
The drug fentanyl is a best seller for dealers, and a prolific killer. It delivers a quick and powerful high that is easy to overdose on. Experts say the synthetic opioid can be 100-times stronger than morphine and 50-times more potent than heroin. Far too often, fentanyl kills.
"It's being mass produced in places like China and Mexico in clan labs by people who are far from educated to be chemists," said Dunbar.
"And it is being shipped in, either internet or through the usual traditional methods, through Mexico and other ports," Rebbert-Franklin said.
The highly controlled narcotic is on the radar of local law enforcement, and law makers in the state because of a recent spike of deadly doses. From 2013 to 2014 the number of people who died and had fentanyl in their blood more than tripled. A total of 185, up from just 58.
"The numbers are going up overall,” said Rebbert-Franklin. “We're seeing more heroin mixed with fentanyl, and we're seeing fentanyl by itself, which is a newer phenomenon."
Heroin has a strong hold here in Maryland. Since 2012, opioids have been responsible for more then 80 percent of all overdose deaths. In 2014 when we saw a steep surge in fentanyl-related deaths, the highly potent drug was laced with heroin in more than half the cases.
The white powder is being mixed to boost the high, but dealers are pushing it, saying its heroin. So users have no idea what drug they're really putting in their bodies.
"You're just playing Russian roulette every time you're sticking that needle in your arm or you're shooting that capsule of what you think might be heroin, that could be heroin and fentanyl or straight fentanyl," said Dunbar.
Micrograms of fentanyl can make the difference between life and death. The drug is so strong, an overdose comes on fast, and the opioid stays in your system longer than others.
Officials say the death toll would be greater if it wasn't for naloxone, the drug that reverses the effects of opioid overdoses.
"It needs to be administered even more quickly than those who are using heroin,” Rebbert-Franklin said. “Death can happen more quickly, and it's more likely when one uses fentanyl."
Sometimes naloxone has to be given more the once to counter the fentanyl.
Still, people keep dying. The final numbers aren't out for 2015, but in just the first nine-months of the year, the fentanyl casualty count is has already matched the total for the year before.
"Now in 2015, our numbers are showing that there's an even greater spike,” said Rebbert-Franklin. “And we're worried for 2016."