Why oxybenzone and octinoxate are banned in Hawaii, Palau, and Key West — and which mineral filters are reef-friendlier.
Lab studies have linked oxybenzone (BP-3) and octinoxate to coral bleaching at low concentrations (Downs et al., 2016). Several jurisdictions have banned both filters in over-the-counter sunscreens.
Where bans apply
Hawaii (since 2021): oxybenzone, octinoxate
Palau (since 2020): 10 'reef-toxic' ingredients
Key West, FL: oxybenzone, octinoxate
Bonaire, Aruba, US Virgin Islands: similar restrictions
Reef-friendlier filters
Non-nano zinc oxide and non-nano titanium dioxide are the standard 'reef-safe' choices. 'Non-nano' means particle size >100nm — less likely to be ingested by coral.
What to look for on labels
Avoid: oxybenzone, octinoxate, octocrylene, homosalate, parabens. Prefer: 'non-nano zinc oxide' as the active ingredient. Note: 'reef-safe' is not regulated — read the active-ingredient panel.
Key takeaways
Oxybenzone and octinoxate are restricted in several reef regions.
Non-nano zinc is the safest active.
'Reef-safe' isn't a regulated term — check actives.
What to do with this Reef-Safe Sunscreen: What's Banned, What's Better data
Sunscreen labels are tested at 2 mg/cm². Typical real-world application is closer to half that, so DermUV assumes about half the labelled SPF when it estimates protected time.
The UV index is a measure of erythemal (skin-reddening) irradiance, where each whole point equals 25 mW/m² of UV energy reaching the surface. That is why burn-time estimates fall roughly by half when the index doubles.
Cumulative dose drives photoaging and long-term skin damage more than any single day. Small daily exposures on commutes, walks, and driving add up across a season.
Reapplication matters more than the SPF number. Reapply roughly every two hours outdoors and immediately after swimming, heavy sweating, or towelling, regardless of what the bottle claims.
Cloud cover is not protection. Thin or broken cloud can still pass most incoming UV, and light cloud edges can briefly scatter more UV toward the ground than a clear sky.
UV scale reference
The WHO scale groups UV 1-2 as low, 3-5 as moderate, 6-7 as high, 8-10 as very high, and 11 or above as extreme. Protection is recommended from UV 3 upward, and shade during the middle of the day becomes the priority from UV 8 upward.
A practical routine at moderate-to-high UV is roughly one ounce of broad-spectrum sunscreen for full-body coverage, applied 15 minutes before going out, then reapplied on schedule. Clothing, hats, and shade carry the rest of the load, especially for children and anyone with a history of easy burning.
Keep exploring DermUV
These pages give more depth around reef-safe sunscreen: what's banned, what's better, from UV-scale reference material to calculators and city forecasts.