SEATTLE (AP) – Public health officials in Washington state have issued a warning about an increasing number of overdoses caused by fentanyl found in black tar heroin.

KOMO-TV reported that the King County medical examiner’s office has identified two fatal overdoses since March where either black tar heroin or a fake black tar substance contained fentanyl.

County health officials say the mix of fentanyl and heroin has not been seen in King County until recently, but has contributed to overdoses in other parts of the country.

Officials say the combination is concerning because people may not know the drug they are taking is laced with fentanyl.

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