Although the performance of oxygen-absorbing sachets was quite satisfactory for a wide range of food storage condition, a number of limitations to their use in practice were recognized. The esthetics of inserts, coupled with a concern about possible ingestion or rupture, as well as their unsuitability for use with beverages, drove researchers to seek package-based solutions. The approach of using the packaging material as the medium for the oxygen-scavenging chemistry was developed independently in several laboratories and countries. Not surprisingly, the reactions were initially the same as used in sachet technologies, but eventually it was recognized that the restrictions applying to package inserts need not apply to the package. This has allowed a multiplicity of oxygen access problems, arising from quite disparate packaging factors, to be addressed, thus permitting targeting of problems at their source rather than waiting for the oxygen to enter the package to be absorbed by an insert, such as a sachet. Some of the chemistries and reaction media used in packaging-material-based systems are summarized in Table 8.1