A mass drug overdose at a home in Chico, California, Saturday morning left one person dead and 12 others hospitalized, according to news reports.

>> Read more trending news

The emergency call came in just after 9 a.m., KHSL-TV reported.

Investigators believe fentanyl or a fentanyl-like substance caused the mass casualty event, according to the news station.

Chico Fire Department Division Chief Jesse Alexander told KHSL that he hasn't seen such a large mass overdose incident in years, and said he saw first responders working on six people at once.

Two police officers who responded to the scene were among those treated after experiencing the effects of the drug. They were treated and released from the hospital, according to KHSL.

Authorities are treating the scene as a hazardous materials site as the investigation continues.