3 dead and first responders rushed to hospital after exposure to mystery substance in New Mexico | 20 May 2026 | Three people have died and 19 others were rushed to hospital after coming into contact with an unknown substance. Authorities were called to a home in Mountainair, New Mexico, on Wednesday to a suspected overdose involving an unidentified substance. According to New Mexico State Police, they arrived to find four people unresponsive inside the home, with three of them having since died. Officials said that during their response 18 first responders were exposed to the substance and transported to hospital. A statement said they are ‘currently being quarantined, evaluated, and monitored’, with two of them listed as being in a serious condition.