BOSTON >> The number of opioid-related deaths in Massachusetts continues to climb, fueled by the use of fentanyl, a powerful synthetic opiate that's often mixed with heroin, according to statistics released Monday by the state Department of Public Health.
There were 1,379 unintentional, opioid-related deaths in 2015, a seven percent increase from 2014.
As recently as 2012, there were fewer than 700 opioid-related deaths in the state.
State health officials said that for the first time the data included information about fentanyl and what they called its disturbing relationship to opioid-related deaths.
Officials said more than half of last year's confirmed opioid-related overdose deaths with a toxicology screen had a positive screen for fentanyl.
Estimates for the first three months of 2016 suggest that the opioid death rate is comparable to the first quarter of 2015.
Republican Gov. Charlie Baker called the data "a key component and tool in continuing to fight this crisis."
The data also appeared to validate the life-saving importance of the overdose reversal drug naloxone — also known as Narcan.
In 2015, state health officials estimated that emergency medical services responded to at least 11,884 opioid-related incidents and administered naloxone 12,982 times.
Official said the data on emergency naloxone treatment closely mirrors trends in the state's opioid-related death data.
Secretary of Health and Human Services Marylou Sudders said the inclusion of data on fentanyl "allows us to have a more honest and transparent analysis of the rising trend of opioid-related deaths that have inundated the Commonwealth in recent years."
In March, Baker signed what he called the most comprehensive law in the nation to combat an opioid addiction scourge, including a seven-day limit on first-time prescriptions for opiate painkillers. Supporters of the limit say most heroin addicts first become hooked on painkillers that were either prescribed or obtained illegally.
Another state law that took effect earlier this year creates the crime of trafficking in fentanyl for amounts greater than 10 grams with punishment of up to 20 years in state prison.
Officials describe the synthetic opioid as 50 to 100 times more potent than morphine and 30 to 50 times more powerful than heroin.
Democratic Attorney General Maura Healey has said the law will help police target traffickers who mix fentanyl with heroin, often without the knowledge of the buyer.
She said fentanyl can be deadly even in very low doses.