JEFFERSON CITY — The Missouri House on Wednesday gave first-round approval to a measure that would make trafficking fentanyl punishable by at least five years in prison.

The proposal would make it a class B felony to knowingly distribute, manufacture, or attempt to distribute or manufacture more than 10 milligrams of fentanyl or any of its derivatives.

A class B felony carries a prison sentence of five to 15 years.

Under the measure, distributing or manufacturing 20 or more milligrams of fentanyl, or attempting to do so, would be a class A felony, which carries a prison sentence of 10-30 years.

Fentanyl, a synthetic opioid pain reliever, is a powerful painkiller used legally for treating pain caused by advanced cancer, according to the U.S. Centers for Disease Control and Prevention. But the drug is also used illegally, and can be mixed with heroin without a user’s knowledge.

“What we are dealing with is an incredibly deadly drug,” said Rep. Nick Schroer, R-O’Fallon, the sponsor of the legislation.

Schroer said fentanyl trafficking is illegal under federal law, but not state law.

“The feds are the only option to deal with the traffickers,” he said.

Schroer called his measure “another tool in the toolbox for prosecutors to use.”

Rep. Peter Merideth, D-St. Louis, wondered whether someone trafficking fentanyl would be deterred by the Legislature’s action.

“Did we come here to keep locking people up for long times?” Merideth asked.

Rep. Shamed Dogan, R-Ballwin, said he was concerned the amount of fentanyl described in the law would be used by prosecutors to sweep up drug users instead of traffickers.

“We’re here to talk about the amounts,” Dogan said. “We have to get this right.”

In 2018, 930 people in the St. Louis metro area died from drug overdoses, up from more than 700 in 2017, according to the National Council on Alcoholism and Drug Abuse.

Fentanyl was involved in the “overwhelming majority” of the deaths, NCADA spokesman Brandon Costerison said in December.

The legislation requires one more vote in the House before moving to the Senate for consideration.

The legislation is House Bill 1450.