I love this site - he has a lot of information about suntanning and what products/chemicals are safe or not! Apparently the jury isn't out on the avobenzone according to this site.
Avobenzone [butyl-methyoxydibenzoylmethane; Parsol 1789] - This is the only chemical sunscreen currently allowed by the European Community. However, its safety is still questionable since it easily penetrates the skin and is a strong free radical generator.
Avobenzone (Parsol 1789) May Not Be Safe Either
In 1997, Europe, Canada, and Australia changed sunscreens to use three specific active sunscreen ingredients - avobenzone (also known as Parsol 1789), titanium dioxide, and zinc oxide - as the basis of sunscreens. In the USA, the cosmetic companies have held off this policy as they try to sell off their stockpiles of cosmetics containing toxic sunscreens banned in other countries.
However, avobenzone is a powerful free radical generator and also should have been banned. Avobenzone is easily absorbed through the epidermis and is still a chemical that absorbs ultraviolet radiation energy. Since it cannot destroy this energy, it has to convert the light energy into chemical energy, which is normally released as free radicals. While it blocks long-wave UVA, it does not effectively UVB or short-wave UVA radiation, and is usually combined with other sunscreen chemicals to produce a "broad-spectrum" product. In sunlight, avobenzone degrades and becomes ineffective within about 1 hour.