Their liquid bomb recipe started with mixing a "piranha bath" - a mixture of sulfuric acid and hydrogen peroxide - that needs to be kept *extremely cold* for a *long* time, or it will turn into instantly lethal gas. If the liquid bomb plot had gone ahead, the near-certain outcome would have been the eventual discovery of an asphyxiated terrorist in the bathroom, lips blue and lungs burned away, face down in a shallow sink filled with melting ice-cubes:
https://en.wikipedia.org/wiki/2006_transatlantic_aircraft_plot
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