A class-action lawsuit filed against the city of Chicago claims that it knowingly started construction projects that have created “elevated and unsafe” levels of lead in the city’s drinking water.

The lawsuit, filed on Thursday in the Circuit Court of Cook County Illinois, claims the city has been aware for years that lead has contaminated the water as a result of street work, water meter installations and plumbing repairs. The suit also alleges the city failed to warn residents about the risk of lead contamination.

The lawsuit comes amid the water crisis in Flint, Michigan, with officials still unable to guarantee that that city’s drinking water is safe.

The complaint says that although the city uses anti-corrosive coatings, the treatments can fail when disturbed by construction or repairs. Additionally, the complaint cites a 2013 study by the U.S. Environmental Protection Agency reporting that homes saw higher levels of lead in their drinking water after construction projects tampered with lead service lines.

“We believe the city of Chicago knew well the risks and dangers of toxic lead contamination associated with these construction projects but chose to turn a blind eye to its own, allowing this mounting problem to become a widespread public health issue across the city of Chicago,” said Steve Berman, managing partner of Hagens Berman, the firm representing residents behind the lawsuit.

The city’s department of water management said in an emailed statement it has not yet reviewed the lawsuit, but added “Chicago's water is safe and exceeds federal, state and industry standards.”

“The Department of Water Management provides the cleanest, best tasting water possible; aggressive programs that protect our water supply from lead and thorough testing methods allow us to continually achieve this goal,” said Gary Litherland, a spokesperson for the DWM.

The DWM said Chicago has a robust anti-corrosion program in which phosphate is used to coat pipes to prevent lead or other materials from entering the water. Residents can also call 311 to request additional, free water testing if they have concerns about the water.

Residents have long been advised to flush their service lines after a new water main installation, in line with U.S. EPA standards, the DWM said. When a water meter is installed, the city performs the flushing for the resident. The city also advises residents to run their water for a few minutes to flush their pipes if water has gone unused for several hours. This can be performed through a shower, laundry, or by flushing toilets.