A man died and four other people were taken to hospitals Sunday morning in a possible drug overdose in a room at the Outrigger Reef Waikiki Beach Resort.

Officials familiar with the case said they are looking at fentanyl as the probable cause of the death and illnesses.

Honolulu Emergency Medical Services said paramedics responded to a call regarding five patients at a hotel on Kalia Road at 6:30 a.m. EMS said it assisted with the death pronouncement of an adult male.

Paramedics also treated two men in critical condition and two women in serious condition, and transported them to hospitals.

Honolulu Police Department officers also responded to the incident.

Outrigger spokesperson Monica Salter said the case is an active investigation and the resort is working with authorities. She said the resort is not permitted to share guest information due to its privacy policy.

Fentanyl and other lab-produced synthetic opioids are driving an overdose crisis deadlier than any the U.S. has ever seen.

Since 2020, drug overdoses are now linked to more than 100,000 deaths a year nationally, with about two-thirds of them fentanyl-related. That’s more than 10 times as many drug deaths as in 1988, at the height of the crack epidemic.

Fentanyl mostly arrives in the U.S. from Mexico and is mixed into supplies of other drugs, including cocaine, heroin, methamphetamine and counterfeit oxycodone pills. Some users seek it out. Others don’t know they’re taking it.

Ingesting 2 milligrams of fentanyl can be fatal, meaning 1 gram — about the same as a paper clip — could contain 500 lethal doses.

That’s driving lawmakers across the country to crack down with harsh penalties, along with adopting measures such as legalizing materials to test drug supplies for fentanyl and distributing naloxone, a drug that can reverse overdoses.

Senate Bill 671, which decriminalizes fentanyl test strips, was passed by the Hawaii Legislature this session and was sent to Gov. Josh Green on April 18.

The Associated Press contributed to this report.