How is hardwood flooring toxic?

The hardwood floors are not all "natural wood" (unless you buy the solid wood. which is in most cases is not what people buy. They buy engineered hardwood) as you might know. It has a core, stains, glues, finishes, etc. All could contain toxic materials. I'd advise you to google for more info.

" All could contain toxic materials. I'd advise you to google for more info. "

I am well aware but you did not say "engineered hardwood". So you are looking for prefinished or site finished engineered wood flooring?

pre finished