While most standard oxygen scavengers contain ferrous carbonate and a metal halide catalyst, there are several non-ferrous variants, such as ascorbate, sodium hydrogen carbonate, citrus and others available [REF].
Typical reasons to use a non-ferrous variant would include the packaging of products intended for international shipping where metal detection would pose a problem; a desire to reduce the odor associated with ferrous carbonate; or dietary products where contact with iron should be avoided [REF].