Health officials say deaths from the powerful opioid fentanyl and fentanyl -related drugs appear to be on the rise in Washington state.
An investigation by several state agencies released Wednesday found at least 70 people died from the synthetic opioid in 2016.
Fentanyl is up to 50 times stronger than heroin and is often mixed with heroin or made to look like other painkillers that fetch a higher street price.
An analysis found that most of the overdoses involved fentanyl sources that were illicit or unknown.
State officials say that direct comparisons between 2015 and 2016 aren't possible because the state's toxicology lab changed its testing protocol last year.
In 2015, using the older method, the lab identified 28 fentanyl-related deaths. That same protocol would have identified 53 fentanyl-related deaths in 2016.
The newer testing protocol found an additional 17 deaths last year.
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