Two environmental nonprofits are suing Taiwanese plastics company Formosa, claiming the company is restricting access to a burial site.

Inclusive Louisiana and The Descendants Project filed suit in federal court on July 9, alleging the company is inhibiting community access to a pre-Civil War site that holds the remains of five enslaved people, according to Verite News.

Formosa in 2018 purchased land in St. James Parish, part of a heavily industrialized area long the Mississippi River known as Cancer Alley, to build a $9.4 billion plastics facility. Its plans have faced significant backlash from residents citing environmental justice concerns over the proposed facility’s air emissions and Formosa’s poor track record of pollution.