East Chicago, Indiana residents are taking steps to open a fifth lawsuit over lead and arsenic contamination. Residents allege city and state officials knew about the pollution as far back as 1972, when the West Calumet Housing Complex was built.

More than 250 current and former residents, including 187 children, filed notices last week that they intend to sue the city of East Chicago.

“The governmental agencies and personnel, including mayors and governors, knew that more than 1,000 people were being exposed to these chemicals everyday, but they did absolutely nothing about it,” Pavlack said in a statement.

Currently, there are at least six lawsuits and administrative complaints pending against a lot of people—the City of East Chicago; local, state and federal agencies; and private companies. Indiana University law professor Anthony Page says this might be a good strategy.

“I would go in and sue as many people as I could. And in the long process of litigation and discovery, it would come out as to who in fact was most likely to be liable,” says Page.

The other lawsuits and complaints have been filed over the past two months. Some are seeking to be named class action lawsuits.

Page says the lawsuits could take at least five years and result in billions of dollars in liabilities.