Video, Test Shows Oxygen Levels Drop into the DANGER ZONE FIVE SECONDS After Putting on a Mask h/t crazy_horse https://www.youtube.com/watch?v=zA9gpF1RNOw&feature=share&fbclid=IwAR01edzSEsP1V4TBM2Bob8if3tVazxjK-cszS200JsopNhRYyQi5MCzBY-k