A review of available information shows that R30 (also known as methylene chloride or dichloromethane, CH2Cl2) has desirable properties as a non-flammable natural refrigerant suitable for use in low-pressure centrifugal chillers. R30 is already used as a non-ozone-depleting substitute for CFCs and HCFCs for many applications, including solvents and foam blowing. Studies show that it is a naturally occurring substance with sources that include oceans, biomass burning, and mangrove swamps. Global environmental properties are favourable with a 100-year GWP of 9 compared to carbon dioxide and an atmospheric life of 0.4 years. Historically, R30 was successfully used in centrifugal chillers and in home refrigerators before the introduction of CFCs. Current handling requirements are similar to those for R123. A thermodynamic analysis indicates that R30 has high cycle efficiency at typical water-cooled chiller conditions. These advantages may allow R30 to compete successfully with synthetic refrigerants in centrifugal chillers.