The potent opiate behind surging drug overdose deaths across the U.S. is now cropping up in the marijuana supply, according to officials in Ohio.

Hamilton County Coroner Dr. Lakshmi Sammarco confirmed Monday that fentanyl, a synthetic opiate roughly 30 to 50 times more powerful than heroin, has been found in marijuana.

The deadly chemical is often cut into heroin supplies to increase the potency and even put into knock-off painkillers. The Drug Enforcement Agency recently warned about fentanyl being increasingly cut into cocaine supplies, reports WLWT.

Sammarco did not specify how many cases she has seen involving fentanyl-laced marijuana and the Hamilton County Corners Office has not reported any deaths linked to the combination.

“We have seen fentanyl mixed with cocaine, we have also seen fentanyl mixed with marijuana,” Sammarco said during a joint press conference with Republican Sen. Rob Portman, according to WLWT. “Essentially, the message we’ve tried to get out there, is if you are using any form of street drugs, count on them having some form of synthetic opioid mixed in.”

There are no confirmed cases of fentanyl-laced marijuana deaths anywhere in the country, but law enforcement officials in Ohio, which is suffering from rampant opioid addiction, have issued recent warnings about the risk. Dave Frisone, director of the Lake County Narcotics Agency in Ohio said June 14 they have had several false alarms regarding laced heroin, but say they “are aware that there is a potential.”

“In regard to marijuana, I’m not familiar with that,” Melvin Patterson, a spokesman for the Drug Enforcement Administration, told Cincinnati.com Monday, regarding fentanyl and pot. “There could be.”

A used needle sits on the ground in a park in Lawrence Thomson Reuters Fentanyl is infiltrating drug supplies across the country because of how cheap the substance is compared to standard narcotics.

While a kilogram of heroin from a Mexican cartel will cost a domestic supplier roughly $64,000, they can order a kilogram of fentanyl through the mail from China for as little as $2,000.

It can also be used to create roughly 20 times more doses than heroin, providing dealers with huge profits.

Officials are particularly alarmed by the increasing presence of fentanyl in cocaine supplies. Police note that, unlike heroin, cocaine is more widely used as a social drug.

They fear that users are largely unaware of fentanyl being cut up with cocaine and say it will have deadly consequences. Less than half a teaspoon of pure fentanyl is enough to kill 10 people.

The New York Times recently culled through data from state health departments and county medical examiners and coroners, predicting there were between 59,000 and 65,000 drug deaths in 2016.