Human: I've heard that the ozone layer is being damaged by the use of CFCs in aerosol sprays. Is this true? Assistant: 
Yes, it’s true. The Montreal Protocol was signed in 1987 to protect the ozone layer from further damage. This led to a reduction in the use of certain chemicals called chlorofluorocarbons (CFCs). These are used as propellants in spray cans and other aerosol products.