State officials called for a united effort in battling the negative effect of a common sunscreen ingredient on coral reefs during an afternoon media briefing at the World Conservation Congress at the Hawai‘i Convention Center.

Drawing on a 2015 research initiative led by the Haereticus Environmental Laboratory head Craig Downs, University of Hawaii research professor Robert Richmond explained how oxybenzone has been implicated in coral larvae deformity, bleaching and DNA damage that weakens coral systems’ adaptability to climate change.

As Richmond noted, such negative effects can occur with oxybenzone concentrations at or below what already exists at many sites frequented by ocean users.

The threat is particularly acute in Hawaiian waters, where ongoing coral bleaching is occurring at a historic rate, beginning in 2014 and likely extending into 2017.

“It’s a huge issue because this is the most long-lasting, extensive coral-bleaching series in recorded history,” he said. “When you add other stressors that cause coral bleaching it affects the ability of coral to be resilient.”

Richmond said oxybenzone exposure is just one of many factors that has undercut the health and long-term survival of coral reefs but is one that can be “easily resolved” at the local level with positive benefits to communities worldwide.

“This is a people issue,” he said. “More than 500 million people worldwide rely on coral reefs for their livelihoods, their economy, their culture and the ecological services, which are estimated at $1 trillion in value around the world.”

Alton Miyasaka, an aquatics biologist for the state Department of Land and Natural Resources’ Division of Aquatic Resources, said there are reasonable alternatives to oxybenzone-based sunscreens that will allow ocean users to enjoy the outdoors without compromising their sun protection.

Miyasaka said zinc oxide and titanium dioxide sunscreen offer comparable protection without posing a threat to coral reef health. He advised those who have already purchased oxybenzone sunscreens to limit their use to nonocean activities like hiking.

Jeff Bagshaw, an outreach specialist with the state Division of Forestry and Wildlife and manager of the Ahihi- Kinau Natural Area Reserve on Maui, discussed ongoing efforts to educate visitors to the reserve about oxybenzone, including face-to-face conversations and distribution of fact sheets and shopping advice cards. Bagshaw said he has also worked closely with retailers and dermatologists to disseminate information.

Bagshaw said one of the biggest obstacles to reducing the use of oxybenzone sunscreen use is the so-called “It’s just me, it’s just today” mentality.

Yet, Bagshaw argued, if half of the average number of people who go to beaches on Maui each day used an oxybenzone sunscreen, the amount of the substance entering the ocean would be a cumulative 55 gallons every day.

Bagshaw noted that most visitors purchase their sunscreen after arriving in Hawaii, a fact that bodes well for coral reef preservation efforts — particularly if local legislators are successful in passing a ban on oxybenzone in the state.

Sen. Will Espero reiterated his pledge to introduce such a bill when the Legislature reconvenes in January.

“We hope to be the first state to ban oxybenzone,” he said. “Let’s create this pebble in the pond that will create a ripple effect.”