Biddeford police say a batch of what people thought was heroin has tested positive for fentanyl, a powerful opiate that can be extremely dangerous if mixed with heroin. They say that two people were hospitalized after showing symptoms of opiate overdose.

Deputy Police Chief JoAnne Fisk said Wednesday that an investigation by the police department’s Street Crimes Unit led to a drug trafficking arrest. Edward Estes, 24, of 45 South Street in Biddeford was arrested Wednesday and charged with trafficking in scheduled drugs. He was held without bail Wednesday night in the York County Jail.

Members of Biddeford’s Street Crimes Unit, the Maine Violent Crimes Task Force and the Maine Drug Enforcement Agency went to the home at 137 South St. and found two people with overdose symptoms. They were taken to Southern Maine Health Care for treatment.

“Of great concern is the fact that the individuals who overdosed believed that they had purchased heroin when in fact they purchased what was mostly fentanyl,” Fisk said in a press release. “There is no safe amount of fentanyl, or for that matter any opiate purchased on the street.”

Mixing fentanyl with heroin or cocaine markedly amplifies their potency and potential dangers, according to the National Institute on Drug Abuse.