(HCFCs) is one of a class of fluorocarbon
compounds that are used primarily as chlorofluorocarbon
(CFC) substitutes. Work on CFC alternatives began in the late 1970s
after the first warnings of CFC damage to stratospheric ozone
. By adding hydrogen
to the chemical formulation, chemists made CFCs less stable in the lower atmosphere enabling them to break down before reaching the ozone layer. However, HCFCs do release chlorine and have contributed more to atmospheric chlorine buildup than originally predicted. Development of non-chlorine
based chemical compounds as a substitute for CFCs and HCFCs continues.