In a creek next to the facility, where the small white beads stand out against the darkness of the sediment, nurdle pollution is obvious. “I think a lot of the pellets or ‘the nurdles’ get caught in the vegetation,” Wilson says. When she bends down to grab a sample of soil—used as evidence in the lawsuit—hundreds of nurdles come up with it.

Wilson’s suit went to trial in March, and last week, a federal judge ruled that “Formosa had historically and continues to violate” the Clean Water Act and its discharge permit. As The Texas Tribune reported, the judge also said that Formosa has failed to report violations to authorities since 2016, which is a separate violation, and that TCEQ has failed to bring Formosa into compliance.

Attorneys will argue in July how much Formosa should be fined, and Wilson says a decision will be announced in August or September.

Often, however, there are few repercussions for polluters, given the challenges of tracing the nurdles back to their origin and tracking down offenders. There is also no database of manufacturers who make plastic pellets and where they ship.

Even so, researchers can generally tell if nurdles are from a new spill. Resin, the core ingredient of plastic, turns yellow in the sun over time, so dark, dingy pellets are typically older than white ones. This can help determine whether a new spill has occurred or whether nurdles that have been out in the ocean for a while are simply washing up on shore.

Evidence can be tricky to gather, however, depending on where the pollution takes place. Within days of the arrival of white-colored nurdles in September on Mustang and Padre Island beaches, which are drivable and also regularly graded, most had been covered up or pushed up against the dunes. And even when nurdles can be traced to a single spill, manufacturer, or location, there is seemingly little to no legal framework for regulating plastic-pellet production.

In 2007, California passed a law intended to prevent the discharge of nurdles into waterways across the state. But more typically, laws that regulate pollutant discharge apply to pollutants like solid waste in general, not nurdles specifically.

Under the federal Clean Water Act, manufacturers can still discharge a certain amount of pollutants into waterways as long as they have a permit. Even that “actually allows them to release a reasonable amount,” Tunnell says.

Read: We’re missing most of the plastic in the ocean

In addition, it is often unclear who is responsible when pollution crosses international borders. In 2017, for example, a storm caused containers filled with roughly 54 tons of nurdles to fall from a ship in Durban, South Africa. By the time the South African authorities began their cleanup attempts, the nurdles had already begun making their way to Australia, and were estimated to arrive about 450 days after the spill, according to Harriet Paterson, a professor at the University of Western Australia who is studying plastics in the aquatic environment.