If you want to keep up with the latest advances in sunscreens — an essential health precaution in Hawaii — you need to ask yourself a few questions.

What kind of sunscreen do you use? Is it mineral- based? Does it contain zinc oxide and/or titanium dioxide? Is the zinc oxide nano or non-nano? Or is it chemical-based? Does it contain oxybenzone and octinoxate?

Those are the easy questions. The harder ones relate to how those ultraviolet (UV) filter ingredients, shed by millions of swimmers at the beach, affect the health of the coral reefs and marine life in Hawaii’s nearshore waters.

Research suggests a danger may exist; but the nature of the problem is extremely complex, and conclusive evidence remains elusive. Still, that has not stopped the state and two counties from acting decisively, motivated by calls from environmentalists to protect Hawaii’s fragile marine environment.

In 2018, Gov. David Ige signed a bill banning the sale of sunscreens containing oxybenzone and octinoxate, two chemicals linked to damage to the marine ecosystem.

“By signing this measure,” Ige said, “we will become the first in the world to enact this type of strong legislation to actively protect our marine ecosystem from toxic chemicals.”

In Maui and Hawaii counties, sales of nonmineral sunscreens are banned as of Oct. 1 and Dec. 1 respectively, essentially leaving only products containing zinc oxide or titanium dioxide available for sale.

Will these measures help?

Some studies suggest that chemical-based sunscreens indeed can cause serious damage to corals; other find that zinc oxide containing nanoparticles can have a similar effect. Skeptics say that research in a lab may not reflect real-world conditions, in which introduced UV filters can be an insignificant drop in the vast ocean. A new report by the National Academies of Sciences, Engineering, and Medicine says more research is needed. That’s certainly true.

Meanwhile, dermatologists fear that further restrictions could limit the availability of effective sunscreens that consumers prefer — such as chemical- based ones that are easy to rub in — thus leading to a reduction in use overall. In Hawaii, 97% of melanomas come from UV exposure, so it’s a real health concern.

Without more definitive answers, what is a consumer to do? Mineral-based sunscreens containing non-nano zinc oxide and titanium dioxide seem the smartest bet for now; but any FDA-approved sunscreen is better than none, as is clothing that protects against UV radiation. Choose wisely, with the environment in mind.