Residents sued Formosa on Monday to force it to comply with the Clean Water Act.
They say Formosa is discharging plastic into waterways and it has been found in fish guts.
Bob Lindsey, one of the residents who brought the lawsuit, said some of the plastic resembles fish eggs.
He said anglers do not typically cut open their catch when cleaning it, so people might consume the plastic without knowing it.
"There's no doubt in my mind that it is certainly not good for the environment or the people who eat the fish," Lindsey said. "Enough is enough."
As of Monday afternoon, Formosa had not been served with the lawsuit, which asks a judge to fine the company $57.45 million.
That money would go to the federal government.
Although both the Environmental Protection Agency and the Texas Commission on Environmental Quality have investigated complaints about Formosa discharging plastic for more than a decade, neither agency has fined the company or its parent company, which is worth billions.
Because of that, residents are able to bring suit on their own.
The residents say they've collected more than 1,600 samples of plastic from the shorelines of Lavaca and Matagorda bays as well as Cox Creek and surrounding wetlands and beaches.
Earlier this year, after the TCEQ's latest plastic investigation, Formosa said employees would vacuum it up every month or whenever it rained.
Diane Wilson, one the plaintiffs, said the problem is persistent and a vacuum would have little effect.
The Advocate asked Formosa spokesman Bill Harvey whether employees were still vacuuming or whether Formosa had taken additional steps, such as changing the way its stormwater or wastewater outfalls are laid out. The company had earlier suspected that was how the plastic was leaving the plant. Harvey did not respond by deadline.
The plaintiffs are part of the San Antonio Bay Estuarine Waterkeeper, an unincorporated association that monitors Lavaca, Matagorda and San Antonio bays and reports its findings to authorities. It was started in 2012 as a project of the Calhoun County Research Watch, a 501(c)(3) nonprofit founded in 1989. Texas Rio Grande Legal Aid's Erin Gaines represents them.
Gaines said studies have shown low-income communities bear the brunt of pollution from industry. She said this lawsuit is a last resort and similar suits have gotten results for residents when regulatory agencies fail to do so.
For example, in April, a federal judge ordered ExxonMobil to pay $20 million after he found it had violated the Clean Air Act at its plant about 25 miles east of Houston, according to the Texas Tribune.
Lindsey returned to Seadrift four years ago after living abroad for decades. When he was a kid, Formosa wasn't his neighbor, and one of the main industries in the area was shrimping. Now, that industry is almost nonexistent.
"That's not completely due to pollution, but it's part of it," he said. "Now there are areas of Lavaca Bay that are restricted from fishing. It's a gradual change that's taken place over such a period that many people don't quite realize how significant it has been. As generations change, they see that as the new normal."
Lindsey said he hopes the lawsuit will change that and allow residents to get back to using the bays as Mother Nature intended.