In 2014, the Pittsburgh Water and Sewer Authority changed the treatment chemical used to prevent the corrosion of lead pipes, which keeps the toxic metal from leaching into drinking water.
The Pennsylvania Department of Environmental Protection said the switch—from soda ash to caustic soda—posed no threat to public health, but the DEP has cited PWSA for not clearing the change with the agency first, as is required by the state's safe drinking water regulations.