Cotton fabrics were finished with Ciba-Geigy's Pyrovatex CP flame retardant and stored for 15 years. These fabrics, which initially achieved the FF 3-71 standard, failed flammability tests (after the storage period) with one laundering. The finish degraded during storage, acidifying the fabrics, resulting in a loss of phosphorus and a gain of calcium during laundering with a high phosphate detergent.