Toxic and noxious were among our top lookups on August 31st, following the appearance of both words in a video posted online. In the video a bevy of reporters are heard querying an executive from a chemical company which had a fire as a result of flooding from hurricane Harvey, and are attempting to get him to commit to whether the smoke from the fire is toxic or not. He seems more interested in referring to the smoke as noxious than as toxic.
Texas chemical plant: Smoke from the fire is “noxious.” Toxicity is “a relative thing” https://t.co/UrPiq2OAKp pic.twitter.com/HZ3dSoQGB7
— CNN (@CNN) August 31, 2017
We provide four distinct senses for meanings of toxic:
1. containing or being poisonous material especially when capable of causing death or serious debilitation
2. exhibiting symptoms of infection or toxicosis
3. extremely harsh, malicious, or harmful
4. relating to or being an asset that has lost so much value that it cannot be sold on the market
Toxic and noxious mean very similar things, but toxic has a connotation of severe harm or lethality more than noxious does. The reporters in the video are clearly asking whether the smoke from the fire is toxic in the sense of our first definition provided above, and the spokesman for the chemical company is apparently choosing the word which carries a less dramatic implication of harm.
Obnoxious and noxious share a Latin root, noxa ("harm"). The earliest meaning of obnoxious was "exposed to something harmful."