Poisoning from mines is also a possibility. When the family was found Tuesday, first responders treated the scene as a hazmat site because carbon monoxide may have leaked out from nearby mines. But the hazmat declaration was lifted Wednesday, and the cause is looking less likely, Mariposa County Sheriff Jeremy Briese told the Fresno Bee. The closest mine Briese told the paper he knew of was three miles from where the family was found.

Source: Washington Post August 23, 2021 11:51 UTC