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Continuous studies into the effects of Ketracel-Whites on the Jem'Hadar have uncovered a way to take away one of their advantages in a controlled environment. A certain gaseous agent, namely dihydro-lithium-tricarbon-quadoxide (affectionately nicknamed "Ketracel-Black") interacts with one of the chemicals in Ketracel-Whites and causes a small but dense cloud of black gas to form continuously. This not only allows the Jem'Hadar to be tracked, but also to be visually detected while shrouded.
This can be incorporated into a ship design such that as soon as any Jem'Hadar comes aboard, this chemical is released into the atmosphere on all decks. Although essentially harmless, prolonged exposure (about 6 hours for another 10 hours.
~Jeremy Lennert, Simon Dark of the 7th Fleet