– At this spring’s “ContaminationFest 2018” in Tacoma, Wash., recycling advocates displayed the kinds of trash that some people mistakenly toss into their blue curbside bins.

“It was everything from dead cats to diapers,” said Alli Kingfisher, recycling and materials management policy coordinator for the state of Washington’s Department of Ecology.

She calls it “wishful” recycling; people imagine that their trash might have some value and should be re-purposed.

Organizers at the Tacoma event, held at LeMay Pierce County Refuse, were trying to educate the community on what’s acceptable and what’s not, based on new recycling restrictions from China. Until Jan. 1 of this year, that’s where a good portion of the recyclable trash exported by the U.S. ended up.

Make no mistake: Animal carcasses and used diapers have never been recyclable materials. But China’s crackdown — banning some items and tightening restrictions on others, including recycling staples like cardboard, scrap metal and plastic — has sent many communities across Washington and elsewhere scrambling to adapt, as trash that once was welcomed by China now could end up in local dumps.

China, which announced last summer that it would no longer accept “foreign garbage” as part of its broader antipollution campaign, initially blocked 24 types of solid waste and added 32 more varieties in April. Those will take effect by the end of next year.

“The Chinese waste import restrictions have disrupted recycling programs throughout the United States and affected tens of millions of tons of scrap and recyclables since they were imposed,” said David Biderman, executive director of the Solid Waste Association of North America. “They are the most important change to these programs in at least a decade.”

Americans recycle around 66 million tons of material each year, according to the Environmental Protection Agency.

Although recycling actually goes back thousands of years, the modern movement took shape in 1970 with the first Earth Day celebration. It’s a multistep process from curbside to recycling plant, where it is sorted — glass, paper, cardboard, plastic, metal — then baled and sent to a mill, which converts the materials into other products.

In Tacoma, the city’s recycling costs have gone up. Additionally, “the costs to market the sorted materials has increased due to the imbalance in supply and demand,” said Megan Snow, a spokeswoman for the city of Tacoma. “Many commodities that previously generated revenues now are a negative revenue stream. And the costs to ship the materials to the alternate markets has increased — shipping rates to China were very low because of the volume of empty containers going back to China. In the short term, the City can absorb these increased costs, but if the markets do not adjust this will not be sustainable longer term with the current rate structure.”

Translation: Consumers could at some point take a hit.

Perhaps a more-pressing question: With China narrowing its doors, where is all this stuff going to go?

The volume will be enormous — 111 million metric tons of plastic waste will accumulate by 2030, with 37 million metric tons of that here in the U.S., according to a new study by researchers at the University of Georgia. (One metric ton equals 2204.6 pounds.)

In 2015, China imported nearly 60 percent of all plastic scrap around the globe; 31 percent of all nonferrous metal scrap (metal that was neither iron nor steel); and 51 percent of all paper scrap, according Global Trade Magazine.

The impact of China’s new policy has been dramatic. In January 2017, the U.S. exported to China more than 208,000 metric tons of mixed paper and nearly 75,000 metric tons of scrap plastics, according to the Solid Waste Association of North America, using data compiled by the U.S. Census Bureau and the U.S. International Trade Commission.

A year later, those numbers plummeted. In January of this year, China accepted just over 11,000 metric tons of mixed paper and 5,000 metric tons of plastic scrap.

Mixed paper, which covers junk mail, magazines, telephone books and more, poses a particular problem.

“There has been a glut,” said Anne Piacentino, director of the Washington State Recycling Association. “Paper bales have been sitting in the Pacific Northwest. That’s not great when you have a lot of rain. That material is not marketable.”

Last year recycling companies, which separate the paper, metals and plastic, then send them to processing plants, earned between $95 and $100 per ton.

This year? Five dollars per ton, according to Brad Lovaas, director of the Washington Refuse and Recycling Association.

“We went through the floor,” he said. “We have to pay people to take it.”

Recyclable scrap had been the United States’ biggest export to China by volume, and was valued at $5.6 billion last year. With a population of nearly 1.4 billion, China had a voracious appetite. American recyclables served as the raw material for manufacturing new products.

But grappling with long-standing environmental problems, China last year decided to ban, as of Jan. 1, 2018, “the import of solid wastes that are highly polluted.”

China only will accept materials such as cardboard, plastic, glass and scrap metal with an impurity level of 0.5 percent, a degree most domestic operations so far can’t achieve. In other words, no grease-stained pizza boxes. They can contaminate an entire batch of recyclables.

“It is very clear they don’t want material that still has to go through another recycling process,” said Adina Renee Adler, senior director for government relations and international affairs for the Institute of Scrap Recycling Industries, Inc. “They don’t want the water bottle. They want a plastic pellet that has been cleaned, separated by color, uniform in shape and in a size that can go straight through to the smelter and that can be melted straight in some new plastic product.”

In addition to educating the public, developing a domestic market for recyclables also is urgent, said Kingfisher, the Washington state recycling policy coordinator.

“We’re a little behind in the game,” she said.