Development and implementation of a safety evaluation program for chemical fibers.

Polyester and acrylic fibers often have prolonged contact with human skin: the sucking of childrens' toys may lead to ingestion. During manufacture, occupational exposure to fiber components may occur. An evaluation of these possible hazards was undertaken by data appraisal, chemical analyses, and animal plus human testing. Occupational exposure limits have already been set for the chemicals used in polymer manufacture. Finishing agents (applied to the fibers) were examined in bacterial mutation and rat acute oral toxicity tests. Finished fibers were tested for acute toxicity and then for sensitizing potential (on guinea pig skin). Human volunteer trials for skin irritance and sensitization followed. No adverse reactions were seen. Only when fibers were burnt was toxicity seen: smoke from acrylic fiber proved more toxic than that from polyester fiber (due principally to hydrogen cyanide release). Migration tests showed that little material leached out from the fibers: < 1 mg/dm2 surface area in saline, 0.4 mg/dm2 from acrylic fibers in methanol, 3.6 mg/dm2 from polyester fibers in chloroform. Analysis showed only fiber polymer components and finish in saline and methanol leachates. Whilst further testing may be required for areas of special concern, since only a limited range of biological endpoints have been addressed, it is concluded that current and foreseeable future uses of these chemical fibers pose little or no toxicological hazard.