n Breakdown of a plastic caused by too long exposure to radiation, or to radiation of too high energy levels, or both. The radiation may be X-ray, electron, gamma, or neutron beams. The mechanism is ionization and chain scission (Mark JE (ed) Physical properties of polymers handbook. Springer, New York; Zaiko GE (ed) (1995) Degradation and stabilization of polymers. Nova Science Publishers, New York; Dissado LA, Fothergill CJ (eds) (1992) Electrical degradation and breakdown of polymers. Institution of Electrical Engineering (IEE), London).