Long before the Environmental Protection Agency existed (founded 1970), before the Clean Water Act (1972), and before "industrial ecology" was a phrase anyone used, the U.S. Public Health Service was already doing rigorous, itemized fieldwork on how factories poison rivers. Public Health Bulletin No. 100, published in November 1919, is a case study of tannery pollution at the Deford Leather Company in Luray, Virginia—and it reads like a modern environmental impact assessment.

The report breaks tannery waste into a taxonomy that would look at home in an EPA permit today:

Wash water from green hides
Wastes from liming vats and unhairing
Wash water from the fleshing and graining floors
Exhausted or spent tan liquors and rinse water from vats in the layaway yard
Excess tan liquors carried by the heads and bellies when removed from the tanning vats
Leakage from leaching vats and a small amount of wash water
Spent alkali and acids from bleaching vats

What's striking is not that the government cared about tannery pollution—the stench of tanneries had driven them to city outskirts for centuries—but that Hommon and Phelps were doing quantitative source apportionment. They didn't just measure the effluent pipe. They separated waste streams by process step and characterized each one, presumably so treatment could be targeted at the worst offenders rather than diluting everything into one lagoon.

Earle B. Phelps is a name worth pausing on. He co-developed the Streeter-Phelps equation in 1925, which models how dissolved oxygen depletes downstream of a pollution source as bacteria consume organic waste. It's still taught in every environmental engineering program a century later. This 1919 bulletin is Phelps' methodology in its early form—the same mind that would soon give hydrology one of its foundational equations was here counting gallons of spent lime liquor draining out of a Virginia leather works.

Was the science right? Yes. Modern tannery waste treatment still targets the exact streams Hommon listed. Chromium (which replaced vegetable tanning for most leather after WWI) added new problems, but the general principle—segregate waste streams at the source, treat each according to its chemistry—is exactly how modern effluent treatment plants are designed. The "end-of-pipe" mixing approach that dominated mid-century industry turned out to be a regression from what Phelps was already prescribing in 1919.

The forgotten wisdom here isn't a technique—it's the timeline. We tend to think of environmental regulation as a post-1960s invention driven by Silent Spring and burning rivers. But federal scientists were systematically studying industrial pollution before Prohibition, publishing under the Treasury Department, using methodology that would still pass peer review. The knowledge existed. What was missing for the next 50 years was the political will to act on it.