A Senate panel advanced legislation Thursday that would permanently put fentanyl and its chemical cousins on the Schedule I list of controlled substances, instead of leaving it there temporarily.

The Senate Judiciary Committee voted 16-5 to report the HALT Fentanyl Act to the full chamber, putting it on course for President Trump’s signature and enactment after the House passed a similar bill this month.

Fentanyl is a synthetic opioid that is fueling the U.S. drug overdose crisis, though Congress has struggled for years to pass legislation that would keep it on the schedule of the most dangerous drugs.

“Permanent class scheduling has been in the works for about seven years now. We’ve had countless debates and discussions over the years, and the end result of those debates and discussions is the HALT Fentanyl Act,” committee Chairman Charles E. Grassley, Iowa Republican, said. “It has already passed the House, and now it needs to pass the Senate.”

Experts say permanent scheduling would result in efficient prosecutions and consistent penalties under guidelines from the U.S. Sentencing Commission while sending a signal to China and Mexico that America is serious about tackling the fentanyl problem as it pressures those nations to do more.

Attorney General Pam Bondi supports the bill.

“This is vital legislation in our fight against the drug traffickers who prey on addiction and profit from Americans’ despair. I urge the Senate to pass the HALT Fentanyl Act, which will empower President Trump and the DOJ to Make America Safe Again,” she wrote on X.

Illicit fentanyl is made in clandestine labs and has an array of chemical analogs. It’s tough for U.S. laws to keep up with every form, so the HALT Fentanyl Act seeks to cover all of the illicit supply and make it easier for prosecutors to win cases.

Some Democrats are leery of the move. They say the legislation could result in overincarceration of drug offenders instead of attacking the root causes of drug addiction.

Yet the House easily passed the HALT Fentanyl Act on a bipartisan vote this month, giving the effort momentum.

The committee advanced the Senate version of the bill, so as a clerical matter Senate Majority Leader John Thune must decide whether to hold a vote on that bill and send it back to the House or simply take up the House-passed version, according to a person familiar with the process. There is no meaningful difference between the House and Senate bills.

During the Senate markup, Mr. Grassley said he wanted to clear up misconceptions about the legislation. The bill would underscore existing penalties for fentanyl offenses and ease burdens on researchers who seek licenses to research legitimate applications for fentanyl and its analogs.

“Patients will have the same access they’ve always had to fentanyl for medical treatment,” Mr. Grassley said. “The legislation does not increase the mandatory minimums or throw up barriers to research.”

Fentanyl started to flood the heroin supply in the middle of the past decade, resulting in an uptick in overdose deaths.

The powerful opioid has shown up in a variety of drugs and counterfeit pills since then, killing Americans of all ages and backgrounds and bedeviling the Obama, Trump and Biden administrations.

The drug still causes tens of thousands of American deaths per year.

“In just a decade, fentanyl has emerged as the deadliest drug in American history,” Sen. Richard J. Durbin, Illinois Democrat, said. “All it takes is 2 milligrams, the fraction of the size of a penny, to cause an overdose.”

Mexican cartels import precursor chemicals, often from China, and manufacture fentanyl. Traffickers press the drug into fake pills, causing unsuspecting Americans to take them and die.

Mr. Trump plans to impose a 25% tariff on Canada and Mexico, saying they haven’t done enough to crack down on illegal immigration and drug trafficking. He agreed to a one-month pause after both countries agreed to stiffer border and drug measures but on Thursday said the tariffs will take effect on Tuesday.

The Centers for Disease Control and Prevention reports provisional data on overdose deaths each month, though the figures lag by nearly half a year.

The rate of U.S. overdose deaths steadily climbed during the COVID-19 pandemic that spanned the last year of the Trump administration and the first years of former President Joe Biden’s term — often topping 100,000 on an annual basis — before turning sharply downward in 2024.

More than 84,000 people died from U.S. overdoses during the 12 months that ended in September, the most recent yearlong data available.

Mr. Durbin encouraged the Senate to promote an array of measures that contributed to the decrease, including counseling and treatment and the prevalence of overdose-reversing drugs such as naloxone.

During committee debate, some senators said they want to work on legislation that targets social media websites that facilitate drug sales. They also want to increase the availability of testing strips that let drug users figure out if the substance they are ingesting contains fentanyl.

• Tom Howell Jr. can be reached at thowell@washingtontimes.com.