 Samples have been found to contain the designer drug U-47700, heroin, fentanyl, and carfentanil .
<clarity>  Samples have been found to contain the designer drug U-47700, heroin, fentanyl, and carfentanil .
 Samples have been found to contain the designer drug U-47700, heroin, fentanyl, carfentanil, and the designer drug U-47700 .