Synonyms for Nontoxic:

adj.

safe (adjective)
nonpoisonous, harmless.

n.

nontoxic (noun)
nonpoisonous, atoxic, edible, nonvenomous, antitoxic, eatable, harmless, comestible.

Other synonyms:

adj.
harmless.
n.
atoxic, nonpoisonous.