a method and apparatus for using liquid nitrogen to render crises safe , as in circumstances of hostage crises , entering methamphetamine labs , purging the accumulating toxic or flammable gases , ending the dispersal of substances from aerosols and capturing the material dispersed by condensing it and sealing it in containers for disposal , picking up spills by solidifying them or gelling the material and containing it for disposal — this includes mercury spills , sealing and repairing broken pipes and dikes and dams , enabling a combustion engine to quit running , changing the conditions in a weather system to counter funnel formation in a tornado threat , strengthening levee structures by freezing the core for the length of the levee when severe crises occur , rapid cooling lava flows to structure the solid lava formation to something useful in that location , purging the coalmine fire environment of oxygen to quell the long - term blaze , and treating industrial stack gas to useful soot , water and carbon dioxide components . these methods can apply in wider circumstances and are enabled by either aperture dispersal of liquid nitrogen or in pipe evaporation for rapid cooling as the nitrogen gas emerges and is released safely into the atmosphere .