In a disturbing new development in the addiction and overdose crisis, forensic analysts in Washington, D.C., have identified a new form of synthetic opioid in the city’s illicit drug supply that is even more powerful than fentanyl, which has been driving a spike in fatalities. The new opioids, known as “nitazenes” and found on syringes, are estimated to be at least several times more potent than fentanyl, and therefore pose a dire threat to substance users. The District saw nearly 500 fatal overdoses over the past 12 months, eclipsing the city’s high homicide toll—which reflects a nationwide surge in overdose deaths to a record 100,000 in the 12-month period ending in April, due largely to the growing presence of fentanyl. It’s not clear yet how widespread the new opioids are, and fentanyl remains the number one killer, as it is now found in contaminated counterfeit medications sold by street dealers as well as sprayed on marijuana. Still, the new opioids carry significant risks because they may not be detected by fentanyl testing strips used to determine the presence of the drug, and might require several doses of overdose reversal drugs to be effective to revive a patient. In addition to Washington, the new drugs have already surfaced in the Midwest, the South, as well as on the Eastern Seaboard, officials say.