Abstract

The expansion of the plastics industry during the last few years has introduced the possibility of hazards from new polymers and from modifications to old products. The first two sections of this paper deal with the diminishing incidence of dermatitis in synthetic resin plants using formaldehyde and with the toxic properties of some chemicals added during the manufacture of polyvinyl chloride compositions. After a brief reference to the hazards of catalysts used in the manufacture of new polymers in the polythene series, an account is given of the dangers of polytetrafluoroethylene. At high temperatures this important new polymer gives rise to decomposition products that may be harmful when inhaled, and smoking contaminated tobacco is one of the commonest ways in practice by which workmen may be affected. Animal experiments have confirmed the dangers of excessive heating of this polymer although the symptoms differ from those in human beings so that it is still not possible to incriminate any one of the products evolved at these temperatures. In a description of the hazards of manufacture of copolymers of butadiene that are new to this country the toxic properties of the monomers are given in some detail since some of these could prove harmful to the factory worker unless adequate precautions are taken, although the final materials are inert and free from danger.

There is an increasing demand for the use of plastics by the general public and in specialized fields. They are widely used in the food industry and for domestic articles so that it is important that both the raw materials and the final article will not contaminate food or beverages. None of the constituents of the plastics should be capable of being extracted by the food or drink with which they come into contact, but in order to ensure this it is more convenient in practice to submit them in the first place to the action of a few selected solvents. Depending on the results of these initial experiments the materials may subsequently have to be submitted to pharmacological tests which may take several weeks to be completed. Three unusual problems in this field are described.

The most difficult application in which to ensure freedom from danger is probably in the surgical use of plastics. Surgeons already have wide experience of the technique of handling and using plastics. Although the effects of a few selected plastics have been investigated and described, the response of living tissues to these materials is often unpredictable. The results of implantation in many patients will not be available for several years and it is suggested that the misuse of plastics in this field presents dangers that may not always be appreciated.