Volatile substances are those that easily transform from a liquid or solid state to a gas or vapor. Many terms can be used as synonyms for volatile substances, including flammable, evaporative, unstable, explosive, and fuming. Other less common synonyms include mercurial, ethereal, and labile. These substances can pose a significant risk to human health and the environment, making proper handling and storage procedures critical. Common examples of volatile substances include cleaning solvents, gasoline, paint thinner, and propane. It is important to note that not all volatile substances are necessarily hazardous, but they all share the characteristic of being prone to vaporization.