Some essential oils, especially citrus fruits, are photosensitive or phototoxic. The essential oils in contact with the UV light from the sun can cause skin damage in the form of burn whose consequences may become difficult to remove. The component responsible for the photochemical action are compounds derived from furan.

 There is a classification for potential of photosensitivity  that is measured by time after application which may be exposed to sunlight without photo-reactivity. For example, the Lime has to wait 72 hours while the Tangerine 24 hours. Anyway I do not think this type of information is safety, it is best to avoid using. It also has another nuance, when some citrus distillates of peel are not photosensitive, and when extracted by cold press are. It is best to be conservative and try not to use these essential oils in products in contact with skin and they are directly exposed to the sun.

In this picture is a severe burn caused by lemon juice. Certainly was preparing a lemonade or … a caipirinha! Did not wash hands and exposed to the sun!