"During an audit last year, federal authorities found an industrial plant had flushed pollutants into Columbia’s sewer system without making sure the contaminants were at legal levels.
But in their investigation, federal officials identified a potentially bigger concern: the city had failed several times to keep track of the industry’s discharges for lead, a toxic metal. Without the proper checks, it was harder for Columbia to know if the plant had released unpermitted levels of lead pollution.
While the city later improved its oversight and the industrial plant promised to improve, Columbia’s misstep highlights the challenges utilities face overseeing a little-known, but important environmental program.
Known as the pre-treatment program, it is intended to limit the amount of industrial waste that can be dumped in public sewers that discharge to rivers, lakes and creeks. But cities and counties don’t always run the program smoothly."