Weapons-grade chemical carfentanil surges as dangerous substitute for fentanyl in U.S.

Kelley Nalewaja stands by a memorial for her son, Michael Nalewaja, seen in the photo, who died after unknowingly taking a lethal cocktail of fentanyl and carfentanil in November 2025, at her home in El Dorado Hills, Calif., Thursday, April 16, 2026. (AP Photo/Rich Pedroncelli)

Nearly two decades after drug addiction sent him to rehab as a teenager, 36-year-old Michael Nalewaja had settled into a quiet life in Alaska where he worked as an electrician.

That all came crashing down days before Thanksgiving 2025, when he and a mutual friend unknowingly took a lethal cocktail of fentanyl and carfentanil they may have mistaken for cocaine.

“I heard the word ‘autopsy’ and I literally just collapsed to the floor,” his mother, Kelley Nalewaja said, recalling the call she received from his wife. “Even if somebody had been there prepared with Narcan — even if somebody had called 911 in time — he was not going to survive.”

Carfentanil, a weapons-grade chemical that authorities say is 10,000 times more potent than morphine and 100 times stronger than fentanyl, has seen a drastic resurgence across the U.S., killing hundreds of unsuspecting drug users.

The rise coincides with a recent crackdown by the Chinese government on the sale of precursors used to make fentanyl. Those regulations are likely prompting traffickers in Mexico to use carfentanil to boost the potency of a weakened version of fentanyl, according to U.S. Drug Enforcement Administration intelligence bulletins reviewed by The Associated Press.

The surge of a drug so deadly that less than a poppy seed-sized amount can kill a person comes as fentanyl seizures and overall drug overdose deaths continue a multiyear decline.

“You’re talking about not even a grain of salt that could be potentially lethal,” said Frank Tarentino, the DEA’s chief of operations for its northeast region, which stretches from Maine to Virginia. “This presents an extremely frightening proposition for substance abuse dependent people who seek opioids on the street today.”

Carfentanil surge

A decade ago, carfentanil exploded into the North American drug supply, causing hundreds of unsuspecting drug users to overdose, only to see a major dip after China banned it, closing a key regulatory loophole in the U.S.

But the situation has shifted dramatically in recent years.

In 2025, DEA labs identified carfentanil 1,400 times in U.S. drug seizures, compared with 145 in 2023 and only 54 in 2022, according to DEA records viewed by AP.

Traffickers in Mexico may be experimenting with producing carfentanil themselves, authorities say, while others could be procuring it from China-based vendors skirting the country’s regulations by spamming online forums in other countries with ads for the drug.

Complicating matters for the cartels are the extreme dangers associated with manufacturing carfentanil, Tarentino said.

“You can’t just dabble in this,” he said. “This is not some mad scientist on Reddit you’re going to get to go out to a rudimentary laboratory in Mexico to make carfentanil.”

Dip in overdose deaths and fentanyl seizures

U.S. overdose deaths have fallen for more than two years — the longest drop in decades. Experts point to several possible explanations, including the overdose-reversing drug naloxone being more widely available and the expansion of addiction treatment. Some have also tied it to the regulatory changes the U.S. has pressed for in China.

Experts say that even multiple high doses of naloxone might not be enough to reverse an overdose when carfentanil is involved.

Fentanyl seizures, along with several other illicit drugs, have also dipped. U.S. Customs and Border Protection reported that fentanyl seizures plunged to about 12,000 pounds (5,443 kilograms) in 2025 — less than half the amount seized in 2023.

But even as fentanyl numbers fall, it remains a major focus of the DEA. Just recently, the agency’s proposed budget included a $362 million increase centered on cartel-driven fentanyl trafficking.

“Anyone who takes a pill that is not prescribed to them by their doctor is playing a game of Russian roulette with their life,” said Sara Carter, President Donald Trump’s drug czar. “But if those terrorists think they can continue this chemical warfare without consequences, they are wrong.”

Researched as a chemical weapon

While the prevalence of carfentanil still pales in comparison to fentanyl, experts are nevertheless alarmed by the increase of a substance researched for years as a chemical weapon and deployed by Russian forces on Chechen separatists in 2002.

The DEA’s annual quota for lawfully manufactured carfentanil — veterinarians use it to tranquilize elephants and other large animals — is just 20 grams, an amount that can fit in the palm of your hand.

“It’s like a biological weapon,” said Michael King Jr., founder of the Opioid Awareness Foundation. “If the world thinks we had a problem with fentanyl, that’s minute compared to what we’re going to be dealing with with carfentanil.”

In 2024, overdose deaths involving carfentanil nearly tripled compared to the previous year, with 413 deaths across 42 states and Washington, D.C., according to the most recent data available by the Centers for Disease Control and Prevention.

“Carfentanil definitely has that potential of spreading throughout the United States unless law enforcement really focuses in on carfentanil and they develop intelligence as to how these drug addicts are getting it,” said Mike Vigil, a former chief of international operations at the DEA.

In recent months, the DEA has documented several large seizures of carfentanil. In October, the DEA Los Angeles Field Division found 628,000 pills containing carfentanil, while in September, officials seized more than 50,000 counterfeit M30 pills from a person at a gas station in Washington state that turned out to be a mixture of carfentanil and acetaminophen.

‘All about money’

In some cases, frequent drug users have become tolerant to fentanyl and are seeking out carfentanil, despite the danger, because of the sudden euphoria it promises, explained Rob Tanguay, senior medical lead for addiction services with Recovery Alberta, a health agency in Canada. It appeals to the drug market, he said, because so little of it goes such a long way toward supply.

“The toughest part about all of this,” he said, “is that this is all about money.”

After Michael Nalewaja’s death, his mother decided against a large funeral.

Instead, she organized a town hall in her hometown of El Dorado Hills, California, bringing together local officials along with mothers who had gone through something similar.

As she grieves her son, an adept salesman full of charisma who had recently gotten a national award by the electrical union, she’s pushing for major legislative and judicial changes so others don’t go through what she did because of a drug she said was never meant for humans.

“It’s not an OD; it’s not an overdose,” she said. “It’s a murder weapon.”

Associated Press writer Joshua Goodman in Miami contributed.

Hallie Golden And Jim Mustian, The Associated Press