Triggering of oxygen-absorbing sachets was an essential feature present from the time they were initially introduced commercially. In that case the trigger was the water necessary for the rusting or iron by the oxygen. In general, this water came from the food and the sachets were not prematurely activated unless exposed to the air for too long. The concept of triggering an otherwise unreaction plastic system was also demonstrated in the 1970s in the singlet oxygen approach to oxygen scavenging (Rooney and Holland, 1979). Around the same time, Rabek and Ranby (1975) showed that the oxidative degradation of a plastic in sunlight was substantial if a photosensitizer and a transition concept of single-dose triggering has been developed and introduced commercially. Speer et al. (1993) were the first to claim that films of unsaturated polymers, such as poly(1,2-butadiene),could very effectively scavenge ground-state oxygen provided they contained a transition metal catalyst and a photosensitizer. The use of pendant C=C double bond was designed to minimize rupture of the polymer backbone during oxidation. This overcame one of the significant drawbacks of the process of Rooney (1982). Speer’s process has been developed with a large number of patent, and has been marketed by the Cryovac division of Sealand Air Corporation under the trade name OS 〖1000〗^TM.