"Chemical-free" is an abbreviation of "dangerous chemical free," or in some cases (for car seats, not so much food), "chemically inert." Nobody would ever have a reason to specify that something should contain no chemicals at all, so the word "dangerous" is dropped in what is essentially an application of Huffman coding. ;)
Artificial toxin/poison/dye/fragrance-free. You can shove as much naturally occurring toxins in the product as you like, and both marketers and regular people will agree it's "chemical-free".
And that's side-stepping the whole "artificial" vs. "natural" nonsense. 'spacehome may be pedantic in this context, but in general, he's right - regular people have their model of the world ridiculously out of sync with reality. Which is of course readily exploited by advertisers selling "chemical free", "natural", "organic" products, which are no better (and sometimes worse) than the "artificial" ones, but still command a premium price.
The types of mommy-bloggers and non-a-list celebs who would think dihydrogen monoxide is a caustic toxin. It's a certain type. You'll know them when you see/read them. ;)
Well it actually is both of those things, if you sit in it long enough you'll melt, if you breathe it in you'll die, so maybe they're smarter than you think :)
Are they selling a vacuum? What could that phrase possibly mean with regards to baryonic matter?