WASHINGTON (WGNO) —The Drug Enforcement Administration sent a letter to federal, state and local law enforcement Wednesday to warn of the potential spike in fentanyl-related mass-overdose events.

According to the U.S. Department of Justice, a fentanyl-related mass overdose event is described as three or more overdoses occurring close in time and at the same location. The agency says it has already happened in at least seven American cities in the past few months.

Cities impacted include Wilton Manors, Florida; Austin, Texas; Cortez, Colorado; Commerce City, Colorado; Omaha, Nebraska; St. Louis, Missouri; and Washington, D.C.

Fentanyl can be found in all 50 states, according to the DEA.

“Fentanyl is killing Americans at an unprecedented rate,” DEA Administrator Anne Milgram said.

The CDC estimated that each year more than 105,000 Americans died of drug overdoses, with 66% of those deaths related to synthetic opioids like fentanyl.

To find out more about fentanyl and other synthetic opioids, visit DEA.gov.