Recreational sun exposure in Puerto Rico: trends and cancer risk awareness. Persons who sunbathe or engage in other activities at the beach are exposed to large amounts of UV radiation. Four hundred seven adults who visited the beaches of Puerto Rico were surveyed to determine their knowledge about the risks of sun exposure and to evaluate sunscreen use. The group consisted of 195 year-round Puerto Rican residents and 212 tourists. Ninety-five percent believed that the sun can cause skin cancer, although only half of the subset who lived all year in Puerto Rico believed that they personally received enough exposure to be at risk. The majority of the group (83%) understood the meaning of the sun protection factor numbers, although 35% used either nothing or a nonscreening oil. Half of Puerto Rican residents rarely or never used sunscreen protection while sunbathing. When sunscreen was used, the most important factor sought was given as sun protection factor (64%), followed by a perceived ability to aid in tanning (26%). 