Abstract: An indicator tag is provided for visually indicating the remaining effectiveness of a protective chemical treatment agent on a textile article. The tag is made from a fabric dyed with at least one dye to impart to the piece of fabric a predetermined initial color which indicates that the chemical treatment agent on the textile article is effective. The dye has a chromophore which is susceptible to degradation by reagents which would destroy the effectiveness of the chemical treatment agent so that exposure of the indicator tag to such reagents causes the indicator tag to change from its predetermined initial color to another color, thereby indicating that the textile article with which the indicator tag is used has been exposed to reagents which may cause a loss in the effectiveness of the protective chemical treatment agent on the textile article.