A surge in overdose deaths related to fentanyl, an opioid 30 to 50 times more potent than heroin, has prompted Baltimore health officials to launch a public health campaign to raise awareness among drug users. Hundreds of people have overdosed on fentanyl across the nation since 2013, often as a result of using heroin that has been laced with the much stronger substance. A quarter of drug overdose deaths in Maryland now involve fentanyl, up from 4 percent in 2013. Opioid overdose can stop a person's respiration, and fentanyl can have this effect very quickly. Other parts of the country such as Detroit and surrounding suburbs are also seeing major surges in fentanyl use and fentanyl-related deaths. In some cases users are unknowingly taking fentanyl in what they believe to be pure heroin, but a growing number of opioid users are deliberately taking fentanyl.