Apparently, certain people who should know better have asserted that "not toxic" does NOT connote safety. They implausibly argue that it's "not the same thing". In other words, the argument goes that if you were to contend that something is "not toxic", it is somehow different than saying that it's "safe". I beg to differ. Certain people apparently think I don't "get it".
We should check that out, don't you think?
I am pretty sure these certain people are native speakers of English, so we can't go there.
Mr. Dictionary stepped up to resolve this difficulty. Here are some definitions that may help sort this out. Some dictionaries do not define "non-toxic", relying instead on the definition of the root word "toxic". I hope you, too, can make this leap.
a. American Heritage Dictionary (Official Edition): This is on my desk for just such an occasion. "Toxic" is defined as "Of or caused by a toxin or poison". The definition of a "toxin" is (in relevant part) "a substance, produced by a plant, animal or microorganism that . . . is capable of producing poisoning when introduced into the body . . . ." A "poison" is "a substance that causes injury, illness or death, esp. by chemical means". So I derive that "not toxic" means that the substance in question will NOT cause "injury, illness or death". I think you might call such a thing "safe".
b. The Free Dictionary: Two definitions of "nontoxic": (i) not producing or resulting from poison, and (ii) safe to eat. So according to this dictionary, "not toxic" means you can eat it safely. Not sure I'd recommend that for, say, a painted glass, but perhaps other people would.
c. Wikipedia: "Toxicity" is defined as "the degree to which a substance is able to damage an exposed organism." So something that is "not toxic" is something that has NO ability to damage an exposed organism. Another word for such a thing is "safe".
d. Thesaurus.com: Perhaps most pertinently, the primary synonym for "non-toxic" is "harmless" and the short definition is "not injurious or dangerous". The full list of synonyms is "controllable, disarmed, gentle, guiltless, hurtless, innocent, innocuous, innoxious, inoffensive, inoperative, kind, manageable, naive, nonirritating, nontoxic, painless, paper-tiger, powerless, pussycat, reliable, safe, sanitary, simple, soft, softie, sound, sure, trustworthy, unobjectionable, unoffensive". [Emphasis added] The antonyms are "bad, destructive, evil, harmful, hurtful, injurious, sinful, wicked".
So, just to be clear, when someone, anyone says something is "not toxic", what they mean is that it is SAFE. This is always the case, even if they flap their arms wildly about . . . for reasons that only they can provide.
Always happy to help.