Henderson should be pristine. It is uninhabited. Tourists don’t go there. There’s no one around to drop any litter. The whole place was declared a World Heritage Site by the United Nations in 1988. The nearest settlement is 71 miles away, and has just 40 people on it. And yet, seafaring plastic has turned it into yet another of humanity’s scrapheaps. “It’s truly one of the last paradises left on earth, and one of the least visited but heavily protected bits of land on the planet,” Lavers says. “But I don’t think I’ve stood somewhere and been so utterly and completely surrounded by plastic.”

The team found several purple hermit crabs that had taken to shoving their junk in junk, using bottle caps and other detritus in lieu of seashells. Other island residents weren’t so lucky; at least one sea turtle had become fatally entangled in fishing line. And the team themselves struggled to cope. “After a while, your brain has to shut off,” says Lavers. “You focus on things like a toy solider or some dice—something that reminds you of something fun from your childhood. That’s the coping mechanism.”

A purple hermit crab on Henderson Island. Credit: Jennifer Lavers

Lavers, a researcher at the University of Hobart, has been documenting the extent of plastic pollution on the world’s far-flung islands for years. She and her colleagues, including Alexander Bond from the Royal Society for the Protection of Birds, arrived on Henderson in 2015, and spent three months counting its junk.

It was not an easy experience. Sure, there were sandy beaches, swaying palm trees, and breathtaking vistas. But the island has no fresh water, and it’s frequently hit by storms that would launch coconuts—or entire trees—onto the team’s tents in the middle of the night. Also, Henderson is a coral atoll, which means that most of its land consists of razor-sharp rocks that sliced their way through the team’s shoes. They ended up scavenging rope from the beach to lash their disintegrating footwear together. “Except for some narrow stretches of sandy beach, the rest of the island wants to kill you,” says Lavers.

On those beaches, the team ended up finding more than 53,000 pieces of human-made debris. By their estimate, the island’s 14 square miles are home to more than 37 million pieces of junk, weighing a total of 17,000 kilograms. Every square meter of Henderson’s beaches has between 20 and 670 pieces of plastic on the surface and between 50 and 4,500 pieces buried in the topmost 10 centimeters. Also, the junk keeps on coming. Lavers estimates that every day, at least 3,750 fresh pieces of litter wash up on the island’s north beach—an accumulation rate that’s 100,000 times greater than what’s been reported at other places.

If these estimates are right, parts of Henderson have the highest densities of plastic debris reported anywhere in the world. But Jenna Jambeck, from the University of Georgia, notes that the data are incredibly variable. And Denise Hardesty, from CSIRO, Australia’s federal research agency, says that it’s hard to compare across sites because different sampling methods can produce vastly different results. Still, whether the numbers break records or not, it’s clear from the photos alone that Henderson is home to an ungodly amount of garbage—as are other supposedly pristine islands.