Carnauba wax comes from the leaves of the Copernicia cerifera palm (also know as 'The Tree of Life') which grows only in Brazil. It is a food grade product. The Food and Drug Administration (FDA) includes carnauba wax in its list of substances considered 'Generally Recognized as Safe' (GRAS) for direct addition to food. It is also PCPC listed (Personal Care products Council).
Although it is part of the emulsifying system, its primary function is to significantly increase water resistance, thus enabling the avoidance of synthetic polymers used in most sunscreens for which water resistance is claimed.