Chemical sunscreens are absorbed by the skin and are not effective until 30 minutes after application. The UV rays are then transformed by the chemical sunscreens resulting in potentially allergenic and phototoxic substances. Also sun care products that contain chemical sunscreens are one of the factors responsible for the destruction of corals.
Indeed these sunscreens promote the propagation of viruses that kill corals. Increasingly certain regions prohibit the use of chemicalbased sun care products on their beaches*

