Bartholomew County Sheriff Matt Myers is warning about a new, even more lethal form of heroin that is being seen on Indiana streets. Authorities are calling it “gray death.”

A Greenwood woman reportedly overdosed on the new mix earlier this week — the first in Indiana.

The heroin mix contains a very powerful animal tranquilizer called carfentanil and a new synthetic opioid called Pink or U-4 that is so powerful that even a grain of it can kill you. Police are warned to be on the look out for the drug as it can be absorbed through the skin, putting rescue workers at risk.

Myers says the drug looks like concrete mix and it could range from chunky material to a fine powder.