[1] Decon foam has been found to make numerous chemical and biological agents harmless.
It is also intended for use in areas where large numbers of people have possibly been contaminated (e.g. at conventions, airports, concerts).
[1] [2] The composition of decontamination foams is essentially water and a surfactant, creating an aqueous film forming foam that various reactive chemicals are then added, diminishing the amount of contaminants adhering to a surface and forming less hazardous products.
Decon foam often comes in multiple bottles, that, when mixed, combine to form the decontamination solution.
This high ratio also allows a small amount of liquid to cover a relatively large area in the event of a major contamination.