How can a nontoxic, nonflammable refrigerant be dangerous?
a. most common refrigerants decompose on contact with air to form flammable substances.
b. the refrigerant can replace all the air in a space, depriving occupants of oxygen.
c. most common refrigerants decompose on contact with air to form toxic substances.
d. concentrated refrigerant can cause euphoric highs that lead to irrational and dangerous behavior

I think the correct answer would be option D. A nontoxic, nonflammable refrigerant can be dangerous because concentrated refrigerant can cause euphoric highs that lead to irrational and dangerous behavior. For example, the refrigerant Freon. Although, it is nontoxic and nonflammable, overexposure to this substance would cause someone to be dizzy and suffer from confusion. Also, it can cause illnesses linked to the central nervous system and the cardiovascular system. This refrigerant is commonly used air conditioning systems and in refrigerators. It is classified as a halocarbon which means it contains halogens. It is a volatile gas with a sweet smell.