The city of Newark, N.J. will test about 17,000 children for lead poisoning after finding lead in the drinking water at 30 schools in the district. About 2,000 toddlers at early childhood centers in those schools will be the first to be tested, Hanaa Hamdi, director of the Department of Health, told the City Council on Tuesday, nj.com reported.

The Early Childhood School on Montgomery Street, was chosen by the district as the first site for tests because young children like the 3-, 4- and 5-year-olds enrolled there face the greatest risk of developing the learning disabilities and behavioral problems associated with lead poisoning.

The action comes after testing revealed that nearly half the district's schools had issues with elevated lead levels in water, according to the Newark Public School system. Of 66 schools, 30 locations have tested positive for lead exposure over the federal legal limit of 15 parts per billion. Lead levels as high as 558 parts per billion were measured, but most results were below 100 parts per billion.

The issue of lead contamination has spread beyond the schools. Newark officials announced on Wednesday that testing for the presence of lead in the water would be expanded to include all public housing complexes. The announcement came as court documents showed that federal prosecutors are conducting a broad investigation into environmental health and safety conditions, including elevated blood lead levels, in New York City’s public housing and homeless shelters.