Sivan Multi-Color Interlocking Exercise Mats

Are these EVA foam mats formamide free?

It might be a slightly different product, but I bought the grey ones a few weeks ago and thus far have been excellent at protecting my floor during work out.
Only take a couple minutes to piece together and take a apart. In the most violent of motions they do slide a bit, but thus far I’ve been ok taking care of that by putting a weight I’m not using at the moment on a couple of the other corners. Granted I also use a total of 12, so the extra friction might help as well.
Any of the jumping motions I’ve done, these mats seem to really dampen the landing from a noise and vibration stand point, which is a big plus in apartment living.
I’d buy again if I had to do all over thus far, but I’ve also only been using every other day for a couple weeks.

I wonder out loud if they would work as an impromptu flooring for a basement?

Yes, it does have Formamide, but the contents are considered safe since its less than 2000PP.