Until someone with more knowhow replies-- I haven't found MSDS for either, but XPE is a closed-cell cross-linked polyethylene, so of course a petrochemical, made usually from high-density polyethene. In itself it probably doesn't outgas, my guess.

I have no idea what glue seals it to bamboo, but it's been suggested that (perhaps under proper mfg conditions) it self-seals to nearly anything, so the glue may be insurance.

Re foam - it's all toxic and outgasses unless it states it is nontoxic. I would suggest you buy flooring without MDF, without glue, and without foam. Costco has a bamboo floor that is "low VOC." I think the near future will bring more of that and eventually "No VOC". Then, go to www.greenBuildingSupply and find out the brand of foam underlayment they use. If you can find it in your area, great, if not, they will ship it to you. All their products are non-toxic, but their wooden floors are very expensive. Check their brands and then you can look for them in your area. Joanne's sewing supplies has a non toxic foam that you can purchase for pillows and reupholstering. Foam pillows and mattresses cause many problems. There are sites that sell non-toxic pillows. The only mattress that doesn't outgas is made from natural latex, but it's very expensive, but very comfortable. Or, you can get a topper for an existing mattress. Barbara P.