The free formaldehyde content, both in parts per million (ppm) and in percentage, was determined by quantitative analysis on 112 fabrics obtained from American textile manufacturers and distributors. This fabric sampling included textiles of 39 different types of composition. All 112 samples, regardless of composition, contained some free formaldehyde. In an analysis of 15 samples of 100% polyester knit and eight samples of 100% polyacrylonitrile (Orlon), it appears that these fabrics, in general, contain less free formaldehyde than those made up of 100% rayon, 100% cotton, 50% polyester and 50% cotton, and fabric composed of 65% synthetic polyester fiber (Dacron) and 35% cotton. Formaldehyde content in this study of clothing samples ranged from 1 to 3,517 ppm.
Schorr WF, Keran E, Plotka E. Formaldehyde AllergyThe Quantitative Analysis of American Clothing for Free Formaldehyde and its Relevance in Clinical Practice. Arch Dermatol. 1974;110(1):73-76. doi:10.1001/archderm.1974.01630070041007