The scientists investigated what can make flammable refrigerants explode and how to prevent it. They found that different methods for measuring these explosions have limitations. Flammable refrigerants can explode when they reach specific concentrations in the air. By testing mixtures of nonflammable and flammable refrigerants, they figured out that adding a certain type of refrigerant can make explosions less likely. They created models to predict the safe concentration levels for mixtures that won't explode: one model used two flammable ingredients and one nonflammable one, while the other had one flammable ingredient and two nonflammable ones.