There are currently 16 active ingredients used in sunscreens in the US, and 14 of them are under scrutiny by the FDA! The two that have proven to be safe and effective are zinc oxide and non-nano titanium dioxide, which are used in mineral sunscreens. In fact, two of the most common chemical sunscreen ingredients, oxybenzone and octinoxate have been banned in several states because of their negative effect on the environment and ocean wildlife.
A groundbreaking new law in Hawaii was passed in 2018 to ban the sale of any sunscreen that contains chemicals that can harm coral reefs. This is the first bill of its kind to be passed in the United States and will hopefully be followed by a ban in Key West on February 5, 2019.
The Hawaii ban of chemical sunscreens will go into effect in 2021 and will specifically target the chemicals oxybenzone and octinoxate. Studies have found these chemicals can lead to coral bleaching (a process that causes coral to turn white and even kill it) when washed off in the ocean. Our coral reefs are vital to help our marine life grow and live.
The only way to know if your sunscreen is reef-safe is to read the listed ingredients. Look for zinc oxide or titanium dioxide sunscreens with the term "non-nano" on the label. Some also specifically say "reef-safe," although it's a safer bet to just look for the ingredients yourself to be sure.
**Referenced from Women's Health Magazine
Nanoparticles are incredibly tiny particles of a given substance. Nanoparticles are less than 100 nanometers thick. To give some perspective, a nanometer is 1000 times smaller than the thickness of one strand of hair.
The terms "nano" and "micronized" are synonymous. So, sunscreen bearing a "micronized zinc oxide" or "micronized titanium dioxide" label contains nanoparticles.