Why was a new refrigerant needed for early household refrigerators?

Early household refrigerators required a new refrigerant because the substances previously used, such as ammonia, posed significant safety risks. Ammonia was considered unsuitable for domestic use because it was toxic, and even a minor leak could release poisonous quantities of gas and produce an unpleasant odor.12

In the late 1920s, Thomas Midgley, Jr. sought a safer alternative and discovered that certain fluorine-containing compounds were remarkably nontoxic, odorless, and possessed the necessary physical properties for refrigeration. These synthetic compounds, later branded as Freon, became the industry standard because they were nonflammable, noncorrosive, and stable.1234

While these halogen compounds successfully addressed the immediate safety concerns of early refrigeration, it was later discovered that they contributed to the depletion of the ozone layer, leading to their eventual global phase-out.34