mephitic vs nontoxic

mephitic

adj

  • Foul-smelling or noxious, particularly of a gas or atmosphere. 

nontoxic

noun

  • A substance that is not toxic. 

adj

  • Not toxic; not poisonous. 

How often have the words mephitic and nontoxic occurred in a corpus of books? (source: Google Ngram Viewer )