It turns out that the primary ingredient in sunscreen is highly toxic to coral. According to a new study published this week, oxybenzone, which is the key UV ray-blocking ingredient in sunscreen, is toxic to all types of coral and is very likely a factor is the global coral die offs of the last dew decades.

Of note, oxybenzone is used today in more than 3,500 sunscreen products, including in very popular brands such as Coppertone, Hawaiian Tropic and Banana Boat.

Sunscreen Killing Global Coral Reefs: Study

More on sunscreen and coral die offs

The new study was published on Tuesday in the October 2015 edition of the Archives of Environmental Contamination and Toxicology, and was was conducted in the U.S. Virgin Islands and Hawaii.

Of interest, the idea for the study came from a random encounter between a group of researchers at Caribbean beach of Trunk Bay and a vendor waiting for the daily horse of tourists. “Just wait to see what they’d leave behind,” he said, “a long oil slick.” That chance comment led to the idea for the research on the impact of sunscreen on coral.

This ground-breaking study came to the conclusion that a very small amount of sunscreen is all it takes to damage the extremely delicate corals. In fact, as little as a drop of sunscreen in a half-dozen Olympic-sized swimming pools, can have a negative impact on corals.

The study also demonstrated three separate mechanisms by which oxybenzone damages coral, preventing the uptake of life-giving nutrients and eventually turning the spectacularly colorful corals into a bleached white.

Of note, the study recorded levels of oxybenzone in seawater around coral reefs in Hawaii and the U.S. Virgin Islands at concentrations  from 800 parts per trillion to 1.4 parts per million, over 12 times the concentrations where coral starts to be damaged.

Also keep in mind that coral reefs are much more than just exotic displays of color on the sea floor. According to the he National Marine Fisheries Service, coral reefs are worth at least $100 million to U.S. fishermen. Coral reefs provide the habitat for much of the fish humans eat worldwide, and offer invaluable protection to hundreds of miles of coastal land from storm surges.

Statements from researchers

“The most direct evidence we have is from beaches with a large amount of people in the water,” noted John Fauth, a co-author of the paper and an associate professor of biology at the University of Central Florida in Orlando. “But another way is through the wastewater streams. People come inside and step into the shower. People forget it goes somewhere.”

Fauth worked on the research project with Craig Downs of the nonprofit Haereticus Environmental Laboratory in Clifford, Va., and Esti Kramarsky-Winter, a researcher from the Department of Zoology at Tel Aviv University in Israel, on the research.

“The use of oxybenzone-containing products needs to be seriously deliberated in islands and areas where coral reef conservation is a critical issue,” Downs explains. “We have lost at least 80 percent of the coral reefs in the Caribbean. Any small effort to reduce oxybenzone pollution could mean that a coral reef survives a long, hot summer, or that a degraded area recovers.”