Octinoxate

Oxybenzone (Figure 1), formally 2-hydroxy-4-methoxybenzophenone, is an old-line sunscreen ingredient developed in the 1950s by the now-defunct General Aniline & Film (GAF) Corp. It is marketed today under several tradenames. The compound was first synthesized in 1906 in Germany by chemists B. König and Stanisław Kostanecki.

The US Food and Drug Administration approved the use of oxybenzone in sunscreen products in the 1980s. In 2013, a revised approval allowed concentrations of up to 6%. Oxybenzone absorbs light in the UV-B (280–315 nm) and short-wavelength UV-A (315–355 nm) ranges.

Octinoxate, or octyl methoxycinnamate (Figure 2), is a more recent sunscreen component. It is marketed by Merck under the tradename Eusolex 2292 and by BASF as Uvinul MC80. It absorbs primarily in the UV-B range.

Both compounds are widely used in sunscreens, but this past May, the Hawaii legislature passed a bill that outlaws products that contain them, effective January 2021. The bill is based on studies that show that oxybenzone may harm coral larvae and that both compounds may “bleach” coral, causing it to lose symbiotic algae.

Sunscreen makers, of course, deny that the studies are valid. Nevertheless, Hawaii governor David Ige signed the bill into law earlier this month.