MOUNTAINAIR, NEW MEXICO — New Mexico State Police responded around 11:00 a.m. Wednesday to a suspected drug overdose at a rural home in Mountainair, where three of four people found unresponsive died and the fourth was transported to a hospital in Albuquerque. More than a dozen first responders were quarantined and assessed for possible exposure to an unidentified substance at the residence east of Albuquerque.

State police arrived at the home to assist the Torrance County Sheriff's Office. Eighteen first responders were exposed to the substance and began experiencing symptoms including nausea and dizziness, and all were transported to the University of New Mexico Hospital for monitoring. Officials at the hospital confirmed that 23 patients exposed to an unknown substance were assessed and decontaminated after being transported there.

Most of the 23 patients were first responders who were asymptomatic and were later discharged, hospital officials said. Medical teams continued to monitor three symptomatic patients Wednesday evening. Two first responders were listed in serious condition, Officer Wilson Silver said.

Mountainair EMS Chief Josh Lewis, who was the first to enter the residence, was hospitalized overnight for observation, Mountainair Mayor Peter Nieto said. EMTs from Torrance County and nurses from University of New Mexico Hospital experienced symptoms after coming into contact with individuals at the scene, he said.

Albuquerque Fire Rescue HazMat teams assisted at the scene to identify the substance. Investigators believe the substance may be transmitted through contact and not be airborne, Silver said. A perimeter had been set up around the home to keep the public away, he said. Yellow police tape surrounded the home on a dirt road in a rural subdivision, and several cars, trucks and vans were parked in the driveway.

Nieto said the health issues were not related to carbon monoxide or natural gas exposure, and that indications were pointing toward narcotics as a possible factor in the deaths. "They don't know if it's narcotics. They don't know if it's something else. They don't know if it's a mixture of the two," he said. He said he was considering closing town hall the next day because of the emotional toll on employees.

Firefighter Antonette Alguire said EMTs and firefighters at the heliport began coughing, vomiting and becoming dizzy after exposure to the substance. "It's getting to that point where we just have to live in fear, even saving lives," she said.