I’m not sure how you define poison. I’ve been involved in a massive freon leak aboard a submarine, and it was handled as a “Poison Gas” event. Many of the crew inhaled enough of the freon to make them very sick. Fortunately, none of us died in the incident.
“I’m not sure how you define poison.”
“The dose makes the poison” - Paracelsus, in the 16th century (or so).
This is a point which has always defied the understanding of Al Gore (and most of the enviro-whackos). Even water (if ingested at high enough volumes - and I don’t mean drowning) and oxygen (at high enough concentrations) are toxic to humans.