The Department of Justice announced Thursday the Drug Enforcement Administration is expanding how fentanyl-related substances are scheduled, thus bringing them to the same illegality and charging level as heroin and marijuana.

A DEA official told reporters that the agency is temporarily scheduling any type of illicit fentanyl analogue as a Schedule I drug — putting it on the same level as heroin and marijuana.

This new scheduling will make it easier for federal prosecutors and agents to criminally prosecute "anyone who possesses, imports, distributes or manufactures any illicit fentanyl analogue" like they already do other controlled Schedule I substances.

According to the DEA official, drug manufacturers are making “tweaks” to the chemical structure of legal fentanyl and other opioid drugs, which allows them to skirt U.S. scheduling laws when importing the drugs.

When the drug manufacturer is caught, prosecutors have to convict under the Analogue Act, a cumbersome process in which the federal government has to prove the drug similar to one in Schedule I or II should be categorized as such, despite molecular alterations.

Fentanyl on its own is a Schedule II drug, meaning it has a high potential for abuse and dependence, but can be prescribed medically. However, altered versions of fentanyl — i.e. an illicit fentanyl analogue — has no legal medical purpose in the United States, and has been linked to more than half of opioid overdose deaths reported in the second half of 2016.

“By scheduling all fentanyls, we empower our law enforcement officers and prosecutors to take swift and necessary action against those spreading these deadly poisons. I also urge the many members of Congress who clearly share our concern and alarm over fentanyl’s role in our opioid overdose epidemic to do their part by permanently scheduling these lethal substances,” Attorney General Jeff Sessions said in a statement.