A single father is suing the D.C. Water and Sewer Authority for $200 million, claiming lead-contaminated tap water poisoned his twin sons as infants, causing them ongoing health problems.

The water utility between 2001 and 2004 hid elevated levels of lead from customers and federal authorities, plaintiff John Parkhurst of Capitol Hill claims in the lawsuit, which seeks class-action status. WASA failed to take steps to remedy the situation, omitted language from public education campaigns that would have warned people about the problem and continued to encourage residents to drink the water, according to the lawsuit filed Tuesday in D.C. Superior Court.

The complaint comes on the heels of a study that determined hundreds of D.C. children might be at risk of irreversible IQ loss, developmental delays and behavioral problems linked to the lead levels. The Children's National Medical Center and Virginia Tech research contradicts claims by D.C. and federal health officials who said in 2004 that although lead in city water was at record-breaking levels, they didn't find any measurable ill effects on public health.