Not sure but maybe concrete is a drug imported & or manufactured in the US?
The drug looks like concrete mix and varies in consistency from a hard, chunky material to a fine powder. It's a combination of several opioids that are tied to thousands of fatal overdoses in the U.S., including heroin, fentanyl, carfentanil (sometimes used to tranquilize large animals, including elephants) and a synthetic opioid called U-47700.
https://www.google.com/amp/s/www.cbsnews.com/amp/news/gray-death-opioid-dangerous-drug-combination/