Motion picture films were the worst, with the highest affinity and the lowest rate of desorption. Fifteen air changes brought it down only to about 100 ppm. The authors recommend sampling the air in the chamber several hours after fumigation is completed. The debate over plastic vs. metal cans for storing film was continued at this meeting, with some enlightenment from relevant research. All of them are problematical because they contain the gases evolved during the process of degradation, which can go on even when oxygen is sealed out.
Metal cans can catalyse reactions in the film that result in release of acids.
Nitrate film frequently corrodes the cans it is stored in, for this reason. She may not have said this explicitly, but some people are recommending that containers be dispensed with altogether, and the vault kept at a low temperature and RH instead. Others are using cans with sensors built into the sides that change color visibly when acids build up above a certain level. Gamma radiation, properly performed on materials, is not a health hazard and does not make the materials radioactive or produce offgassing like EtO. It is used routinely in some Eastern Europe institutions. The problem is that it degrades the materials to a certain extent, and since it does not have a lasting effect, in practice it would have to be repeated on the same materials every time there was an infestation.