The legal drug that killed Prince was 50 times stronger than heroin - and overdose deaths are creating an 'unprecedented' epidemic

Although the deadly drug is legal with a doctor's prescription, it's also being made illegally in underground labs and traded across the US.

A new CDC report, released August 25, found that from 2013-2014:

• Incidents of law enforcement officers finding drugs containing fentanyl jumped 426%.
• Deaths from synthetic opioids like fentanyl rose by 79%.

"In contrast to the 2005-2007 fentanyl overdose outbreak, when deaths were confined to several states, the current epidemic is unprecedented in scope," the report states.

Here's what you need to know about it: