This is likely carfentanil. It is being imported cheaply from other areas and is being used to mix with other drugs such as heroin or fentanyl. If you come in contact with it, you have a pretty good chance of dying just by touching it or getting it on your skin. Multiple doses of naloxone may be needed to reverse its effects. It is a big problem for police officers and first responders.
This is what they used (in an aerosolized form) in Russia during the theater hostage crisis several years back. It killed the terrorists, but also killed most of the hostages.