Switching to the Flint River as the city’s primary water source was an attempt to save around $5 million over the course of two years in Flint, Michigan.

Instead it has cost $458 million.

That’s according to calculations from analyst Peter Muennig at Columbia University's Mailman School of Public Health. Only $58 million of that is expenditure by the state on medical care and unleaded water. The bulk of the number includes the social costs: Exposures leaking IQ points from children and disposing them to aggression and violence later in life, which leads to lower economic productivity, greater dependence on welfare programs, and greater costs to the criminal justice system.

The lifelong bill for each case of low-level lead poisoning is about $50,000 and 0.2 years of perfect health, based on CDC data. Flint has already seen more than 8,000 documented exposures, while each year there are some 90,000 across the country. When it comes to low-level exposure, Muenning and many others believe that drinking-water is the most common source. Chewing on paint tends to cause higher lead levels.

Muenning explained to me that while the chain of events may not be immediately evident, it’s important to follow backward as a matter of avoiding a common fallacy: considering the costs of action (primarily in economic and financial terms) while ignoring the costs of inaction. Those costs can be rendered in the interest of maximizing human well-being or simply protecting a municipal bottom line, depending on one’s priorities.

Either way, confronting the cost up-front—for public-health measures as for so many things in life—tends to be difficult. It also tends to divide people along political lines.

“Hopefully these numbers generate some feedback and controversy,” he laughs.

I wondered if there were something controversial about his calculations that I was overlooking.

“No,” he explained, “I just think it’ll be controversial because people feel weird about spending money on social programs.”

Hence the case for cold numeric calculation. Previous calculations have estimated that for every dollar spent preventing lead poisoning, the benefit would be $10.50. Even with return like that, Muenning sees it as politically unviable to spend the necessary tens of billions of dollars to identify all houses built within with a risk of lead leaching into the water supply and trying to replace their pipes. “That might fly in Scandinavia, but not here,” he said.

Instead he advocated a more realistic approach to targeted intervention in the highest-risk areas. That is the approach of the federal government’s Office of Lead Hazard Control and Healthy Homes, which has nonetheless been receiving less funding year over year.

If the numeric cost argument isn’t convincing in the wake of the Michigan tragedy, the other cold number to consider is 1760. That’s the number of years of healthy human life that have been sacrificed due to lead poisoning in Flint so far.