So which of the following count as "man made" chemicals?
Alcohol or vinegar from humans intentionally fermenting things?
A metallic aluminum alloy?
Sulfuric acid (which sometimes occurs naturally)?
Turpentine?
Soda-lime glass?
I get that it generally refers to substances that are more on the very artificial side, requiring advanced knowledge of chemistry to produce, and to have a connotation of harmfulness / toxicity. But it's not at all obvious what the speaker would consider to be a "chemical" because that varies from speaker to speaker.
Alcohol or vinegar from humans intentionally fermenting things?
A metallic aluminum alloy?
Sulfuric acid (which sometimes occurs naturally)?
Turpentine?
Soda-lime glass?
I get that it generally refers to substances that are more on the very artificial side, requiring advanced knowledge of chemistry to produce, and to have a connotation of harmfulness / toxicity. But it's not at all obvious what the speaker would consider to be a "chemical" because that varies from speaker to speaker.