State lawmakers on Wednesday approved a bill criminalizing the trafficking of fentanyl, a synthetic opioid dealers add to heroin to make the drug more potent. Attorney General Maura Healey has pushed for the legislation, which would impose prison sentences of up to 20 years. "Today, Massachusetts took an important step in the fight against heroin and prescription drug abuse," said Healey, in a statement. "Fentanyl is the most powerful opioid painkiller available – it is up to 50 times stronger than heroin. Drug cartels have figured out how to manufacture it, and they are mixing it with heroin and taking lives across our state." The state already outlaws possession of fentanyl with the intent to distribute, but that is a lesser crime that comes with lesser penalties.