For months, a major recycling facility for the greater Baltimore-Washington area has been facing a big problem: it has to pay to get rid of huge amounts of paper and plastic it would normally sell to China.
Beijing is no longer buying, claiming the recycled materials are "contaminated."
For sure, the 900 tonnes of trash dumped at all hours of the day and night, five days a week, on the conveyor belts at the plant in Elkridge, Maryland — an hour's drive from the US capital — are not clean.
Amid the nerve-shattering din and clouds of brown dust, dozens of workers in gloves and masks — most of them women — nimbly pluck a diverse array of objects from the piles that could count as "contaminants."
That could be anything from clothes to cables to tree branches to the bane of all recyclers: plastic bags, which are not supposed to go in recycling bins because they snarl up the machinery.
"We've had to slow our machinery, and hire more people" to clean up the waste, says Michael Taylor, the head of recycling operations for Waste Management, the company that runs the plant.
At the end of the sorting line is the end product — huge bales of compacted waste containing paper, cardboard or plastics.
These have been bought up for decades by businesses, most of them based in China, which clean them up, crush them and transform them into raw materials for industrial plants.
Last year, China bought up more than half of the scrap materials exported by the United States.
Globally, since 1992, 72 percent of plastic waste has ended up in China and Hong Kong, according to a study in the journal Science Advances.
But since January, China has closed its borders to most paper and plastic waste in line with a new environmental policy pushed by Beijing, which no longer wants to be the world's trash can, or even its recycle bin.
For other waste products such as cardboard and metal, China has set a contamination level of 0.5 percent — a threshold too low for most current US technology to handle.
US waste handlers say they expect China will close its doors to all recycled materials by 2020 — an impossibly short deadline.
"There is no single and frankly, probably not even a group of countries, that can take in the volume that China used to take," warns Adina Renee Adler of the Washington-based Institute of Scrap Recycling Industries.
The Waste Management facility in Elkridge manages to sell its plastic bottles to a buyer in South Carolina and ships its cardboard abroad.
But its haul of mixed paper and mixed plastics is effectively worthless, and the plant pays subcontractors to haul it away.
Other US recycling plants have broken a major taboo and no longer bother sorting plastic and paper, and instead simply send it straight to landfills.
"Nobody wants to say it out loud, because nobody likes the fact that they're having to do it," said Bill Caesar, the head of waste company WCA in Houston.
Waste Management and Republic Services, another industry heavyweight, have admitted doing it under limited circumstances, while some small towns, particularly in Florida, have simply stopped collecting recyclable waste.
Other scrap importer countries such as Indonesia, Vietnam or India are incapable of absorbing the tens of millions of tons that China had previously taken.
And few American industries possess the ability to treat the waste.
"The biggest issue here is that China just gave very little time for the industry to transition," said Adler.
Darrell Smith, president of the National Waste and Recycling Association, added: "Eventually we will have such a large backup that more and more will have to start being diverted to landfills if we don't find new markets and new uses for the recycled materials."
The messy problem is starting to get punted down the line to cities and towns during the renegotiation of municipal contracts.
That is compounded by the fact that many cities already have ambitious recycling targets: Washington wants to see 80 percent of household waste recycled, up from the current 23 percent.
The US capital already pays $75 a ton for recycling, compared to $46 for waste that is burned to generate electricity.
"There was a time a few years ago when it was cheaper to recycle. It's just not the case anymore," said Christopher Shorter, director of public works for the city of Washington.
"It will be more and more expensive for us to recycle," he said.
To avoid mounting costs, according to Shorter, the city wants to "better educate our residents about what should and should not be recycled" — especially about not putting plastic bags in the blue recycling bin.
And to further reduce the amount of waste being recycled or burned, Washington is considering offering a third trash can to residents for organic waste, and building a facility to compost it.
And the city is thinking of making residents pay based on the weight of the waste they produce.
In Houston, WCA's Caesar has a warning for Americans: "They're going to have to start paying more for the privilege of recycling."