Once released from containment there is no way to return cryogenic materials to their containers. The cryogenic liquid will absorb heat from its surroundings, enabling gas to form or boil. High concentrations of gas can lead to depleted or enriched oxygen atmospheres and flammable vapours at hazardous concentrations.
The only options to re-establish a safe atmosphere are to disperse or contain the gases that have already evaporated and/or prevent the release of any further cryogenic liquid.
See Hazard – Flammable vapours (unignited) for further information.