A new synthetic drug that is 100 times stronger than fentanyl is causing concern as the battle against the deadly opioid crisis continues.

Carfentanil is a tranquilizer used for large mammals, and it's 10,000 times more potent than morphine. It has already proved deadly in Maryland and New Hampshire.

Just last week, the Queens DA announced the largest seizure of its kind of carfentanil. Officials say they seized 11 pounds of the drug when they busted a trafficking operation that stretched from California to New York. They also seized cocaine, fentanyl and heroin.

Steve Chassman, who is with the Long Island Council on Alcoholism and Drug Dependence, says officials have not yet seen the presence of carfentanil on Long Island.

"Eleven pounds of carfentanil, given the lethality of that opioid, could potentially take out all five boroughs and the population in it," says Chassman.