Researchers have been studying new refrigerants for the past 15 years to find safer options than older ones like hydrocarbons and CO2. They've discovered that even though some refrigerants can be toxic, using flammable ones can be safe if handled properly. By looking at how fast a substance burns and its minimum ignition energy, scientists can classify refrigerants by their flammability levels. An upcoming international system will help differentiate between different levels of flammability for safer use. This classification is crucial for reducing the risks of using flammable substances in refrigeration systems. In the future, low-GWP refrigerants will need to prioritize safety in relation to either toxicity (especially for ammonia) or flammability, to be used more safely based on the amount of refrigerant and cooling capacity needed.