Oxybenzone and octinoxate are probably bad for reefs.

Yes, but the science is messy and the real damage might be smaller than you think.

The studies that got everyone worried were done in lab settings with concentrations way higher than what you’d find in the ocean. In real seawater, UV filters from sunscreen are present but usually at levels below what caused coral bleaching in those experiments. Other factors—rising ocean temps, pollution, overfishing—are way bigger threats.

That said, I’d still avoid them. The precautionary principle is worth applying here. Mineral sunscreens (zinc oxide, titanium dioxide) work fine and don’t have this controversy. Just don’t fall for “reef-safe” labels—that’s largely unregulated marketing. Look at the ingredients yourself.

The real practical answer: use a mineral sunscreen if you can, but don’t beat yourself up if you forget. The coral’s bigger problem is climate change, not your beach day.