BALTIMORE (AP) _ Health officials are warning Baltimore residents that drug overdose deaths linked to a highly potent chemical commonly used to lace heroin are up 178 percent from last year.

Officials say there were 39 overdose deaths in Baltimore associated with fentanyl in the first three months of 2015, compared to 14 fentanyl-related deaths in the same time period last year.

City Health Commissioner Dr. Leana Wen called the rapidly increasing rate of fentanyl-related overdose deaths “a public health emergency.”

As part of an overdose education campaign, the health department is circulating a flier that advises drug users to never use alone, and to carry Naloxone, which counters the effects of an overdose.