Iran has developed chemical weapons based on synthetic opioids such as fentanyl, warns a US expert, powerful agents that could incapacitate soldiers or civilians when added to grenades or artillery.

Pharmaceutical-based agents, or PBA, are essentially weaponized medicines that incapacitate or kill their victims depending on the exposure. Iran may have given PBA to its proxies such as Hezbollah, which could use them to kidnap Israeli troops and civilians.

“At a time of growing regional instability in the Middle East, largely the result of the militancy of Iranian proxies, the threats posed by Iran’s weaponized PBA program can no longer be overlooked,” wrote Matthew Levitt in an article for the Combatting Terrorism Center at West Point.

The U.S. Government Accountability Office defines PBAs as “chemicals based on pharmaceutical compounds, which may or may not have legitimate medical uses, and can cause severe illness or death when misused.” They include opioids such as fentanyl and tranquilizers for animals.