Farmers are raising the alarm about the amount of plastic they’re finding in compost and soil made from the island’s green waste and they say Oahu’s main compost provider isn’t doing anything to stop it.

“I’m seeing the plastic probably three, four times a week,” said Tommy Irwin, a landscaper who works with gardeners and farmers across the island. Hawaii Earth Recycling is the island’s largest compost provider, turning more than 140,000 tons of yard clippings, food scraps and wood every year into soil, compost and mulch for plants.

The City and County of Honolulu pays Hawaiian Earth Recycling $866,990 a year to accept green waste from more than 160,000 Honolulu homes. Any leaves, grass clippings or Christmas trees you throw in the green waste bins are taken to Hawaiian Earth Recycling to be composted.

“I walked back in there and I said … so do I get a discount because I’m taking your garbage with it?” Irwin said. “They didn’t give me a response.”

Plastic Is Forever

While composting is an attractive solution for dealing with many types of waste, microbes in a compost pile aren’t able to decompose plastics.

“It’s something an awful lot of people have concerns about and I really understand those concerns,” said Caitlin Youngquist, a compost and soil expert with the University of Wyoming extension. She said plastic pollution is a growing issue for the composting industry.

Instead of disintegrating, plastic just crumbles into smaller and smaller bits. The big pieces Irwin is finding in his soil today will one day be tiny fibers.

“This whole entire area has now been ruined with microplastic,” said Irwin, gesturing to Hawaiian Earth Recycling’s field in Wahiawa where white plastic bags can be seen sticking out of giant piles of compost and dirt.

“They will never be able to get it out now and who’s paying for that? Our grandchildren, our future farmers that need food from this area,” he said.

Hawaiian Earth Recycling canceled a planned tour with Civil Beat and declined multiple interview requests.

Safety Measures

Hawaiian Earth Recycling’s compost is certified by the U.S. Composting Council, and it sends compost samples to a lab for quarterly testing.

Frank Franciosi, executive director of the U.S. Composting Council, said the lab should count the number of plastics it can see in a sample during the initial screening. But the composter is the one sending in the samples.

“And unfortunately microplastics are something that the naked eye can’t see and it is an issue,” he said.

Although you have to have a permit from the Hawaii Department of Health to sell compost in the state, DOH isn’t testing the product or overseeing day-to-day production.

“Our oversight is primarily through education, complaint response, permitting and, if necessary, enforcement,” said Lene Ichinotsubo, chief of the state’s Solid and Hazardous Waste Branch. DOH is primarily focused on water sources being affected by the compost-making process, not on the final compost product, she said.

On its website, Hawaiian Earth Recycling says its the “only licensed facility to make and sell compost on Oahu monitored by the State Department of Health,” which Ichinotsubo said isn’t true. Three other composters on Oahu have permits to sell their products.

Sorting It Out

David Souza’s company, Island Topsoil, creates and sells about 3,000 tons of compost a year in Waianae. It’s a small amount compared to Hawaiian Earth Recycling’s production, but he says he’s able to be picky about what he uses.

“I have someone looking through everything that comes in and we pick out plastics, needles, metal, dead animals — you’d be surprised about what comes in,” he said.

“Although they’re my competition — well, I don’t know if I can call them my competition because they’re so much bigger than I am — but I do wish they wouldn’t grind all that nonsense in their compost because it affects the farmers,” he said.

Cheyenne Lurvey, who cares for an agroforest in Pupukea, said Hawaiian Earth Recycling’s product didn’t used to be this way. A few years ago small transfer stations across the island stopped accepting green waste. Those stations acted as “the first checkpoint,” where staff could ensure plastic wasn’t in the waste, he said.

Now landscapers and tree trimmers must take their green waste to one of Hawaiian Earth Recycling’s facilities in Wahiawa, Waimanalo or Kapolei. Lurvey and Irwin said there’s no longer anyone checking their trucks when they drop off green waste.

Lori Kahikina, director of Honolulu’s Department of Environmental Services, declined Civil Beat’s interview request but said in an email that Hawaiian Earth Recycling does sort plastic out of incoming green waste and completed compost.

Hawaiian Earth Recycling’s website says that individuals dropping off green waste are responsible for ensuring their loads are free of “plastics and other non-compostable materials,” but Natalie McKinney of the Kokua Hawaii Foundation said it’s not landscapers and tree trimmers that are the problem. She said it’s Oahu residents.

“They think they can put leaves from their yard in a plastic bag and put that in a bin. No, they need to empty the garbage bag into the bin and put their bag in the trash bin,” McKinney said.

McKinney has worked with Hawaiian Earth Recycling to inform people living on Oahu about the dangers of putting plastic in their green waste bins, and the county Department of Environmental Services says it educates residents about proper procedures.

Green waste bins in many Oahu neighborhoods only say plastic bags should be avoided “as much as possible.”

“I don’t want to put all the blame on Hawaiian Earth because then our taxes will go up,” said Lurvey. “But they need to figure it out and people can’t just be throwing whatever in the green bins.”

All Around Us

Irwin and Lurvey are on the front lines of what scientists around the world are realizing: our soil is contaminated with a lot of microplastics.

“While we’ve known about microplastics in marine environments, soil is really an emerging field,” said Jo Rochester, a scientist specializing in hormone-mimicking chemicals, like BPA, that are found in plastics.

Rochester pointed to new research showing that very, very small microplastics can make their way from the soil into plants.

“I don’t think it’s crazy to be worried about this because we know toxic chemicals can leach off of microplastics and affect you,” she said. “And the actual physical microplastic itself can do weird things once it gets into your body.”

Rochester said scientists are in the beginning stages of understanding how exactly these microplastics affect human health, and advancements have been slow.

“You can’t really dose an animal with microplastics … all exposure is environmental,” she said.

It’s one of the reasons there isn’t a regulation on how much plastic can be in compost, although there are strict rules on things like heavy metals, salmonella, fecal coliform and pH levels.

While many plastics washing up on Hawaii’s beaches come from other countries, there’s no one to blame but Hawaii residents for plastics in our soil.

“We need to address the problem at the source which is the proliferation of plastics we use every day,” said state Rep. Chris Lee. “Ultimately those costs for cleanup are going to be passed on to local farmers and the agriculture industry because nobody wants to have plastics leaching toxins into fields where food is being grown.”

“Are We Doomed? And Other Burning Environmental Questions” is funded in part by grants from the Environmental Funders Group of the Hawaii Community Foundation and the Frost Family Foundation.