Tiny pellets called 'nurdles' are leeching into the ocean. A new Shell plant could produce 80 trillion of them a year.

When heavy winds swept through Hong Kong during a storm in July 2012, hundreds of millions of tiny, plastic pellets — each one no bigger than a lentil — fell off a freight ship.

The particles, known as "nurdles," spread through the water around Hong Kong and blanketed the shore. A local cleanup volunteer told the New York Times that she'd waded through knee-deep piles of plastic.

The incident was a stark reminder of this common, yet little known, form of pollution. Each year, around 250,000 tons of nurdles leach into the ocean. Researchers are concerned that marine animals could mistake these particles for food sources like fish eggs. Scientists have found nurdles in the digestive tracts of birds and fish, though they're still working to determine the health risks for these species.

Nurdles can spill on their way to becoming 'virgin' plastic

Manufacturing companies use nurdles to make virgin plastic — plastic that hasn't previously been recycled. The particles are deliberately small (around 2 to 5 millimeters in diameter), which makes them easier to transport and mold into plastic products like food packaging, containers, phone cases, or car parts. These virgin-plastic items are generally cheaper to make and sell than recycled plastic, and they aren't as vulnerable to degrading over time the way recycled plastic products are.

But during transit, there's always a risk that nurdles could fall from railroad cars or spill out of production facilities and make their way into nearby waterways. 

In 2018, thousands of pounds of nurdles wound up in a stream in Pennsylvania after a semi-truck that was carrying them crashed along a highway. The following year, piles of nurdles washed up on Sullivan's Island beach near Charleston, South Carolina. The state's Department of Health and Environmental Control later attributed the pollution to a spill from a local shipping company. 

After the nurdle spill in Hong Kong, the government warned people to wash their fish thoroughly in case the animals had ingested the particles, which led to a dip in fish prices. The plastic also washed up during the spawning season of green sea turtles, whose environment was supposed to be protected from June to October. 

Read more: Scientists have created magnetic coils thinner than a human hair that could break down plastic in the ocean

Shell is building a new 'nurdle' plant in Pittsburgh

In the US, oil and gas companies have plans to build more than a dozen new facilities that support the virgin plastic industry. That includes a new Shell facility north of Pittsburgh, which President Donald Trump recently visited. (The facility gained national attention after the Pittsburgh Post-Gazette reported that its contractors were required to attend a Trump speech in August in order to receive their paychecks.)

Construction on that facility could take another 8 years, but once complete, the plant is slated to produce around 1.8 million tons of plastic, or around 80 trillion nurdles.

It is also slated to have its own rail system, with 3,300 freight cars to transport the pellets to manufacturing centers. Production facilities like Shell's typically use vacuum-like hoses to carry the pellets to these cars. But Miriam Gordon, the director of the advocacy group Upstream, told Quartz that process can result in spills at the attachment point between the hose and the freight car.

If nurdles were to be released into the environment in Pittsburgh, there's a risk that they could travel to nearby waterways like the Ohio River. (Shell has organized yearly cleanups there to remove litter.)

"When we start producing product, we will commit to zero pellet, flake, or powder loss into the environment from handling operations," Shell said in a statement to Business Insider. The company added that it is collaborating with local groups in the Pennsylvania community to encourage more plastics collection and recycling. 

California is the only state with a law that identifies nurdles as a pollutant, which allows it to penalize nurdle producers under the Clean Water Act, a federal law that makes it illegal to discharge pollutants into waterways.

However, as researchers learn more about how nurdles affect human health and marine life, that information could inform how states decide to target such pollution in the future.

For now, scientists suspect that the small bits of plastic that people ingest through food or drink could carry toxic chemicals like phthalates and bisphenol A (BPA) into our bodies. Nurdles can also absorb contaminants like mercury or the insecticide DDT from rivers and oceans. But the risks to human health are still unknown.