First responders were exposed to fentanyl and sickened after arriving at a rural New Mexico home Wednesday to investigate a possible overdose that left three people dead, officials said Friday.

Four people were found unconscious at a home in Mountainair, east of Albuquerque and two were declared dead at the scene, officials said.

A third died enroute to the University of New Mexico Hospital, officials said.

The fourth survived. Both the survivor and one of the deceased had been administered the overdose medication Narcan.

More than a dozen first responders were quarantined following the call after exposure to an unknown substance, with some reporting nausea and dizziness, officials said.

“Preliminary findings indicate this incident is tied to the exposure to a powdered opioid substance within the home and on scene DEA laboratory analysis has confirmed the presence of fentanyl, methamphetamine, and para-fluorofentanyl, also called P4 fentanyl. It’s a more illicit form or version of fentanyl,” New Mexico State Police Chief Matt Broom told reporters.

The fentanyl was in powder form, police said.

“These men and women responded to a dangerous situation while working to protect lives and secure the scene,” Broom said. “We especially recognize the first responders who became sick while carrying out their duties.”

Mountainair EMS Chief Josh Lewis was among those exposed. Mayor Peter Nieto had previously said Lewis was likely the hardest hit.

“He’s one of the first that went into the residence,” Nieto said. “That’s what we’re thinking — he was the one that got the most of it.”

Five dogs from the home were also placed in quarantine at Mountainair Animal Control.

This is a developing story. Please check back for updates.