A second lawsuit has been filed against a gas supplier in connection with a 2016 gas leak in central Illinois that contained private wells.

The lawsuit filed in Champaign County Circuit Court accuses Peoples Gas of contaminating drinking water when a large amount of natural gas was leaked into the Mahomet Aquifer.

The action Monday by 21 residents brings to 38 the number of people who are suing Peoples Gas because of the leak from Manlove Field, an underground natural gas storage facility. The situation came to light when residents in the Mahomet area began noticing issues with their well water.

People’s Gas spokesman Brian Manthey said in a statement the company is reviewing the lawsuit and “doesn’t have any substantive comments on the lawsuit at this time.”

More than 500,000 residents rely on the Mahomet Aquifer in Central Illinois.