Here is what I have learned about hardwoods.

Many woods do cause allergic reactions, mostly from the dust when cut. Certain woods can cause allergic reactions when handles green and a couple when dry. All those allergies are specific to the person. Some people are affected, many are not affected.

Interior wood flooring needs to have a finish applied. For protection of the wood and for protection of people and allergies.

All of the wood finishes of which I am aware are safe when dried/cured. The problems with finishes are those created when the finish is applied and those problems are caused by the material used to liquify the finish material. This is driving the change over from oil based finishes to water based types. Water based finished are much less toxic when applied/curing.

A good example of this is shellac. While not a really long lasting or desirable floor finish, shellac was used as a finish for trim in houses for many years. The material used to liquify shellac is alcohol. Usually denatured, but vodka or whisky would also work. If denatured alcohol is used, the shellac mix is poisonous---because of the denatured alcohol. Once dry, the same shellac is edible. And, if mixed with vodka(or other drinkable alcohol) it could be consumed with only the hangover as an aftereffect(I would probably not like the taste, however!). Shellac is used as a finish on some candy.

If those companies use a factory applied finish, it will be safe for pets/people---unless consumed.

There is a Flooring Forum in Gardenweb. You could also try posting your questions there. I saw this thread that gives several company names for hardwood flooring with low VOCs. One company they mention is Mercier, but they mention a few others. The thread is from 2015, so not sure the information is still accurate.

Thread about hardwood flooring companies and chemicals/VOCs

If you are concerned about chemicals, have you looked into buying unfinished flooring then having it finished on site?

How did we all live this long without worrying about what kind of wood and the chemical composition of the finish? Once the wood and finish are dry, what possible difference could it make? The finish is a jillionth of an inch thick how much of anything could it contain?

Yes--look at warranties and quality, but anyone who drives a car (or worse, lets their 9-year old son ride in a car) yet worries excessively about danger from these finishes does not understand the concept of risk.

What do you think wood is made of if not chemicals?

Thank you all for your input and suggestions. Richfield95, that's a good idea, and we are going to look into that tomorrow. Our contractor had said prefinished because of time, but I like the idea of unfinished so as to pick our finish and also avoid dust-collecting bevels. :) Thanks!

And you go down yet another rabbit hole with even more VOCs emitting inside your house for weeks.