Textile products bearing the Oeko-Tex 100 certification mark:
Do not contain allergenic dye-stuffs and dye stuffs that form carcinogenic arylamines.
Have been tested for pesticides and chlorinated phenoles.
Have been tested for the release of heavy metals under artificial perspiration conditions.
Formaldehyde is banned; other aldehyde limits are significantly lower than the required legal limits.
Have a skin friendly pH.
Are free from chloro-organic carriers.
Are free from biologically active finishes. (Thanks to the Two Sisters Ecotextiles blog for this information)