An Associated Press investigation has found Chinese companies offering to export a powerful chemical that has been killing drug users and is so lethal it presents a potential terrorism threat.

The AP identified 12 Chinese businesses that said they would export carfentanil, a synthetic opioid, to the U.S., Europe and elsewhere for as little as $2,750 a kilogram (2.2 pounds), no questions asked.

Carfentanil is the latest scourge in an epidemic of opioid abuse that has killed tens of thousands of people. Dealers have been cutting carfentanil into heroin and other illicit drugs to boost profit margins.

Despite the dangers, carfentanil is not a controlled substance in China, where it is legally manufactured and sold online. The U.S. is pressing China to blacklist carfentanil, but Beijing has yet to act.