As everyone knows, the Montreal Protocol created a sea change in a number of industries, including air-conditioning, refrigeration, and foam insulation, as manufacturers in those segments had to scramble for alternatives to the chlorofluorocarbons (CFCs) being used for refrigerants and blowing agents.
Montreal also engendered two other effects. One, it permanently wedded those segments to new externalities. Companies must now weigh technology decisions in the context of how climatology and politics may interact to produce new regulations.
In the old days, most companies used the same methods for the same applications. Today, companies head off into different directions with their alternative technologies, sometimes as a result of internal preferences, sometimes as a result of regional market imperatives.
Exhibit A for the splintering effect is blown polyurethane foam insulation, where most companies used CFC-11 in the pre-Montreal era. When that proved challenging to quickly replace, many shifted to HCFC-141b, which was approved as a temporarily acceptable, interim blowing agent.