The aerosol container has enjoyed com. success in a wide variety of product categories.Insecticide aerosols were introduced in the late 1940s, and shave foams, hair sprays, deodorants, paints, perfumes, whipped cream, and automotive products followed in the 1950s.Medicinal metered-dose aerosol products have also been developed for use in the treatment of asthma, migraine headaches, and angina.Aerosol products are hermetically sealed, ensuring that the contents cannot leak, spill, or be contaminated.The packages can be considered to be tamper-proof.They deliver the product in an efficient manner, generating little waste, often to sites of difficult access.By control of particle size, spray pattern, and volume delivered per s, the product can be applied directly without contact by the user.All aerosols consist of product concentrate, propellant, container, and valve (including an actuator and dip tube).The propellant, said to be the heart of an aerosol system, maintains a suitable pressure within the container and expels the product once the valve is opened.Propellants may be either a liquefied halocarbon, hydrocarbon, or halocarbon-hydrocarbon blend, or a compressed gas such as carbon dioxide, nitrogen, or nitrous oxide.Worldwide, use of CFC propellants, designated as Propellants 11, 12, and 114, is strictly limited to specialized medicinal aerosol products such as metered-dose inhalers.The most popular aerosol containers are the three-piece, tin-plated steel container and the aluminum container.All aerosols are produced by either a cold-filling or pressure-filling process.Barrier packs utilize a plastic bag or piston to sep. the product from the propellant.