Hanauma Bay Nature Preserve attracts nearly 1 million visitors a year from around the world, and supporters of a bill making its way through the state Legislature say the preserve’s coral reefs need protection from harmful chemicals found in popular sunscreens.

Senate Bill 2571, introduced by Sen. Mike Gabbard, seeks to prohibit the sale and distribution of over-the-counter sunscreens containing the more commonly mentioned oxybenzone as well as octinoxate. They held a sunscreen swap and rally Wednesday at the state Capitol, hoping to garner enough support to push the bill through this session.

“There’s more and more scientific research coming out about the dangers that oxybenzone and octinoxate pose to our coral reefs, marine life and human health,” Gabbard said in an email.

Leading up to the session, Gabbard said a coalition of concerned parties formed Hawai‘i Reef and Ocean Coalition, and this is one of their top priorities.

With their input, he introduced the bill, which crossed over to the House and now heads to conference committee.

“There is a clear and present threat to the coral reefs that tourists love the most,” said Craig Downs, executive director of the Haereticus Environmental Laboratory, a nonprofit based in Virginia. “Hanauma Bay, ‘Ahihi Bay, Honolua Bay, Kapalua Bay. Now the West Coast of Maui. Most of the reefs are gone.”

Downs recently conducted a study at Hanauma Bay, where he and volunteers sampled water on Nov. 17, 2017, examining levels of oxybenzone, which can make coral more susceptible to bleaching.

A total of 10 water samples were collected representing the coral reef closest to the beach. The average concentration of oxybenzone in Hanauma Bay was was 4,661 nanograms per liter of seawater. The lowest was 30, and the highest, 27,880 nanograms per liter of seawater.

His conclusion was that Hanauma Bay “is experiencing intolerable levels of oxybenzone sunscreen pollution.” If nothing is done to reduce this, he said, the bay will degrade to the point where it no longer will be a sought-after resource for locals and tourists alike.

All one has to do, he said, is look at coral reefs in West Maui or the Florida Keys.

Supporters of the bill include Friends of Hanauma Bay, Sustainable Coastlines Hawaii and the Office of Hawaiian Affairs. Supporters said alternative, mineral-based sunscreens, which feature zinc oxide and titanium dioxide, are available on the market.

Lisa Bishop, president of the Friends of Hanauma Bay, said she is deeply concerned about the survival of the inner coral reef at the “crown jewel of Oahu.”

“It is the No. 1 environmental tourist destination, so it has suffered the greatest effects from oxybenzone pollution and we can fix that,” she said. “There’s a lot of the inner reef already dead over the last 30 years, and if we don’t take care of this, within the next 15, 20 years, the inner reef will be dead.”

The gift shop at Hanauma Bay voluntarily stopped selling sunscreens containing oxybenzone, she said, and is working on plans to expand outreach and education to visitors.

Testimony in opposition to the bill came from Bayer, which manufactures Coppertone sunscreens; the Hawaii Medical Association; Hawaii Food Industry Association; Personal Care Products Council; and American Chemistry Council.

Bayer said there are limited, active ingredients available within the U.S. with the same proven effectiveness as oxybenzone for sunscreens over SPF 50. The Hawaii Medical Association said it wanted the issue to be studied more deeply because there was a lack of peer-reviewed evidence suggesting sunscreen is a cause of coral bleaching, and overwhelming evidence that not wearing sunscreen increases cancer rates.

The HFIA, which represents distributors of food and beverage products, said “higher standards of review” were needed to “ensure that taking this action would indeed improve outcomes for reefs.”

Some private companies, such as Hawaiian Airlines, are taking initiative on their own, without legislation.

This month the airline announced it would be offering free samples of Raw Elements’ reef-friendly sunscreen to passengers on flights from North America to Hawaii and airing an in-flight video, “Reefs at Risk.” Aqua-­Aston Hospitality and Outrigger Resorts also support reef-safe sunscreen initiatives.

Robert Richmond, a research professor and director of Kewalo Marine Laboratory run by the University of Hawaii at Manoa, was at the rally Wednesday to support the bill.

“It’s not to say if we stop using oxybenzone, reefs are going to live happily every after,” said Richmond. “For me it’s death by a thousand cuts. If we can stop several hundred cuts today, that’s how we can buy time to deal with these other compelling issues in the future.”