harmless vs nontoxic

harmless

adj

  • Not intended to harm; inoffensive. 

  • Incapable of causing harm or danger; safe. 

nontoxic

adj

  • Not toxic; not poisonous. 

noun

  • A substance that is not toxic. 

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