Sunscreen can prevent the most common types of skin cancer — basal cell and squamous cell carcinomas — but it does not protect against melanoma, a more rare but deadly type of skin cancer, according to a researcher from Memorial Sloan-Kettering Cancer Center in New York.
Those who used sunscreen did not have a lower risk of melanoma, even though it has been theorized that preventing sunburns in childhood with sunscreen might lower the risk of cancer.
There are now some researchers who believe that the skin exposure to chlorine that we have through bathing and swimming in chlorinated pools is the main reason we have an increased incidence of melanoma. It is NOT the ozone.
The chlorine exposure in combination with excessive sunshine probably contribute to the increase rate of melanoma that is seen.