Fact Check: How Deadly Is Fentanyl?

Fact Check: How Deadly Is Fentanyl?
Fact Check: How Deadly Is Fentanyl?

Right now, one of the biggest public health threats the US faces is an epidemic of opioid abuse. Too many Americans are using powerful painkillers, and some of them are dying because of it. The most prolific killer is fentanyl, a synthetic opioid that’s a hundred times as strong as morphine. Of course, all medications can be dangerous if abused, but some people are saying fentanyl is uniquely lethal. Last month, Senator Ed Markey (D-MA) claimed that 118 pounds of fentanyl could kill over 26 million people, and warned of the risks of it being used as a weapon of mass destruction. Is this accurate? Could a painkiller become a terrorist superweapon?


  • Fentanyl was first produced in Belgium in 1959 and quickly became a popular drug. It’s used as both an anesthetic and an analgesic, and is very effective — many doctors see it as the drug of choice for the most painful cancers. Medical fentanyl can be administered as tablets, transdermal patches, nasal sprays or even flavored lollipops.
  • Unfortunately, as a powerful opiate, fentanyl has also become popular with illegal drug users. Since the 1970s, it’s been widely abused, either on its own or mixed with heroin or other drugs. Addicts use both stolen medical fentanyl and illegally produced variations.
  • Although it’s an effective medicine, fentanyl is also a dangerous one. It’s produced a steady string of deaths since it came into use. High-profile casualties include musicians Tom Petty and Prince, who both died from accidental fentanyl overdoses.
  • The reason it’s so easy to overdose is that it’s so powerful. That’s medically useful — it doesn’t take much to treat even severe pain — but it doesn’t leave much margin for error. Take too much of any opioid and you’ll stop breathing and die; with fentanyl, “too much” isn’t much at all.
  • According to the FDA, the LD50 of fentanyl — the amount that will kill half the people who take it — is just 0.03 milligrams per kilogram of body weight. That works out at 2.1mg for a 155-pound person — less than a ten-thousandth of an ounce.
  • By comparison, hydrogen cyanide — a potent chemical weapon — has an LD50 of 3 milligrams per kilogram of body weight. It takes 210 milligrams to kill a 155-pound person, and hydrogen cyanide is a very lethal substance. Fentanyl is a hundred times as deadly.
  • Senator Markey’s figures aren’t actually correct, but they’re not a million miles from the truth either. A 118 pounds of fentanyl works out as the LD50 for 26.8 million people who weigh 155 pounds or less, so if it was evenly distributed among 26.8 million people, approximately half of them would die.
  • In reality, it would be impossible to distribute it so evenly, but an attack with fentanyl could still potentially kill tens of thousands of people. For example, if a few pounds of it was sprayed over the crowd at a sporting event there would be mass casualties.
  • Fentanyl has already been used as a weapon. When Russian special forces stormed a Moscow theater during a hostage rescue operation in 2002, they pumped in a fentanyl-based gas first to immobilize the terrorists. It worked — but it also killed 130 of the 850 hostages.
  • There definitely is a risk of terrorists weaponizing fentanyl to use against us. That makes it even more important that we close our borders against drug smugglers and criminals before it does happen.