Severely cold (-60° C to -270° C) and pressurized liquids.  They present an explosion hazard due to high pressures and can cause thermal damage to living tissue.

A refrigerated liquefied gas with a boiling point colder than -130*F.

a liquid with a boiling point at atmospheric pressure below -150 degrees Celsius. [SEMI C3-94

Generally, a cryogenic liquid is any liquid with a temperature less than -101.1 degrees C. Liquid oxygen and liquid nitrogen are the most common cryogenic liquids encountered. Some common gases-such as ammonia, natural gas, chlorine and hydrogen chloride-are often shipped as cold liquids but are actually cryogenic liquids. Certain components of chemical protective clothing ensembles, especially elastomeric gloves, can become stiff and brittle when exposed to these liquefied gases.

Cryogenic liquids are liquefied gases that are kept in their liquid state at very low temperatures and have a normal boiling point below -238 degrees Fahrenheit (-150 degrees Celsius). All cryogenic liquids are gases at normal temperatures and pressures. These liquids include methane, oxygen, nitrogen, helium and hydrogen. Cryogens normally are stored at low pressures.