An Old Orchard Beach woman was arrested after a Tuesday traffic stop turned up a half pound of fentanyl in her car.

Cassandra Gasbarro, 33, was charged with aggravated trafficking in schedule W drugs, a Class A crime, according to the Maine Drug Enforcement Agency.

Gasbarro was driving on the Maine Turnpike in Wells on Tuesday evening when she was stopped by state troopers and drug agents, who suspected her of purchasing large quantities of fentanyl in Massachusetts and bringing it into Maine, where she allegedly sold it throughout York County.

A subsequent search of her vehicle turned up half a pound of fentanyl, worth an estimated $45,000, the Maine Drug Enforcement Agency said.

Fentanyl, a powerful synthetic opioid, is up to 100 times more potent than morphine, according to the U.S. Centers for Disease Control and Prevention. Just 3 milligrams can cause a fatal overdose. There are nearly 265,000 milligrams in a half pound.

Gasbarro was being held on $10,000 bail at the York County Jail in Alfred. She was scheduled to make her first appearance in court on those charges on Friday.

A Class A crime is punishable by up to 30 years in prison and up to a $50,000 fine.