China has announced it is banning a deadly synthetic opioid called U-47700 and three other synthetic drugs. In China, U-47700 has until now been a legal alternative to fentanyl and potent derivatives like carfentanil. Its usage has been growing among US opioid addicts. Last year, the US Drug Enforcement Administration listed U-47700 in the category of the most dangerous drugs it regulates, saying it was associated with dozens of fatalities, mostly in New York and North Carolina. Some of the pills taken from Prince's estate after the musician's overdose death last year contained U-47700. Deng Ming, deputy director of the National Narcotics Control Commission, said the drugs would be added to China's list of controlled substances as of July 1.