Cryogenic Liquids and Dry Ice

Cryogens, such as liquid nitrogen and helium, are liquefied gases that are kept in their liquid state at very low temperatures.   Dry ice is solidified carbon dioxide.  Both items can present unique hazards due to the low temperatures and potential for rapid expansion to the gaseous state.  This SOP describes the main hazards, ways to mitigate these, and safe work practices.