Margo on Troesken, _The Great Lead Water Pipe Disaster_

[eh.net-review at eh.net]

Published by EH.NET (June 2007)

Werner Troesken, _The Great Lead Water Pipe Disaster_. Cambridge, MA: 
MIT Press, 2006. x + 318 pp. $30 (cloth), ISBN: 978-0-262-20167-4.

Reviewed for EH.NET by Robert A. Margo, Department of Economics, 
Boston University.


Werner Troesken (Professor of History at the University of Pittsburgh 
) is the kind of scholar who makes the rest look dull and 
unproductive. In _The Great Lead Water Pipe Disaster_, his second MIT 
Press monograph in two years (with many journal articles in between), 
Troesken examines the historical origins of a serious environmental 
hazard -- the use of lead pipe in water delivery. Lead, not to put 
too fine a point on it, is bad news if ingested in sufficient 
quantities -- which, as these things go, is pretty minute. 
Unfortunately, water running through lead pipe can pick up the metal 
along the way. In a hazy sort of way, the hazards of lead pipe have 
been known for a very long time but the specific relationship between 
dosage and harm proved much more elusive to scientists. If this were 
not enough, industry self-interest obfuscated the science at crucial 
junctures. This is hardly a story unique to lead, as a glance at the 
history of environmental regulation would tell.

Following a "Prologue" that sets the stage, _Great Lead_ is divided 
into eight substantive chapters, a conclusion, and three technical 
appendices. Chapter One begins by reminding the reader that a toxin 
small enough to be invisible to the naked eye might still have 
horrible consequences. Lead, according to Troesken, is such a toxin. 
Cities throughout the world in the mid-to-late nineteenth century 
installed lead service pipes to deliver water to the masses. 
Historically, lead levels in water were many orders of magnitude -- 
500 times, approximately -- as large as maximum current standards as 
set by the U.S. Environmental Protection Agency. Troesken asks a 
simple question as in: "Hello? Is Anyone Home?" It is not like our 
ancestors, recent or otherwise, were completely ignorant of lead's 
toxicity. Why did they install lead service pipes? Equally strange, 
why did it take so long for some cities (Cape Town, South Africa, and 
Glasgow, Scotland, the subject of Chapter 9, being two examples) to 
dismantle their lead water systems? The book makes the following 
arguments. First, depending on location, historical levels of lead 
did have serious health consequences, principally (if not 
exclusively) for the unborn, young children, and pregnant women. 
Second, the adverse effects of lead varied with the chemical 
characteristics of the water supply. Third, public health officials 
tended to judge adverse effects by looking at adults, and here the 
effects were confusing to discern unless lead levels were off the 
charts, so to speak. Fourth, lead pipes were used because they were 
cheap. Fifth, the legal system allocated liability to consumers, who 
were supposed to take care not to become sick by drinking 
lead-infused water -- except that consumers, according to Troesken, 
rarely knew enough to know what they were drinking; and when they 
did, often could not take appropriate preventive steps.

Chapter Two reviews the scientific literature on lead poisoning. Like 
most of the other chapters, it opens with an historical anecdote. 
Erasmus D. Fenner was a New Orleans physician who tried to marshal 
evidence that lead pipes were harmful in colic outbreaks in the Big 
Easy. He was unable to do so, according to Troesken, because he 
lacked a scientific model to explain his correlations. What did 
Fenner need to know? First, lead if ingested is more harmful in 
infants and children than in adults. Second, at high dosages, there 
are symptoms of lead poisoning that are plainly visible; but at low 
to moderate dosages, which cumulatively can be harmful, lead 
poisoning can be very difficult to detect, largely because it can 
produce contradictory symptoms. Third, lead is bad for one's health 
because it mimics calcium and zinc in the body and can thus throw off 
physiological processes like nerve conduction.

Chapter Three considers just how much lead was present in municipal 
tap water at the turn of the twentieth century. One reference 
standard would be today's EPA maximum recommended dosage; by this 
standard, lead levels ca. 1900 were astronomical. Another standard is 
the amount of lead in diachylon pills, an over-the-counter "remedy" 
to induce abortion. To reach the manufacturer's recommended dosage of 
diachylon to achieve the intended result, a resident of Attleborough, 
Massachusetts ca. 1900 would only have to drink 12 ounces of tap 
water per day. Exactly what one should make of such a comparison is 
not immediately clear to me but in one of the technical appendices 
(see below) Troesken presents econometric evidence from 
turn-of-the-century Massachusetts towns positively linking water lead 
levels to infant mortality rates (see below). Chapter Four studies 
eclampsia, a convulsive disease specific to pregnancy, very dangerous 
to the woman and her unborn child. Historically eclampsia was a 
serious medical problem but only recently have medical researchers 
been able to show that prior exposure to lead can increase the risk 
of the disease. Chapter Five continues the survey of the historical 
evidence on lead poisoning arguing that significant fractions of the 
adult population ca. 1900 (10-12 percent in the case of 
Massachusetts) harbored unhealthy levels of lead in their bodies.

Chapters Six and Seven focus on legal matters. Chapter Six elucidates 
the doctrine of protective power, which held that lead water pipes 
were safe because the interior of the pipes developed a protective 
coating that prevented the lead from dissolving in the water. The 
doctrine, however, was faulty as a general rule. Water alkalinity and 
acidity are important chemical facets but even with a good deal of 
prior information it can be extremely difficult to predict ex ante 
whether lead pipes will be a problem. Chapter Seven notes that courts 
routinely held consumers liable for drinking lead-contaminated water 
even though on Coasian grounds one would suspect that water companies 
were the least cost suppliers of alternative piping. Troesken also 
claims that consumers were poorly informed about the hazards of lead 
in any specific case, as were plumbers, and other relevant service 
providers. Being well-informed might not be useful anyway because 
municipal governments often mandated the use of lead.

Chapter Eight examines the history of lead pipes in Glasgow, 
Scotland. At the start of the nineteenth century, Glasgow had a 
terrible water system, to put it mildly, and things only got worse as 
the city grew from industrialization. The city fathers eventually 
settled on a plan to build an aqueduct from Loch Katrine. The water 
from this source was exceptionally pure but also very soft. Everyone 
was so pleased with the new water supply that, a few lone voices 
aside, no one noticed (or cared) that once Katrine water hit the 
service pipes in Glasgow, lead levels rose to dangerous levels. 
Glasgow residents had to suffer until 1979 before the authorities 
dosed the water with lime, thereby correcting the lead problem. 
Glasgow, Troesken argues, is a telling counter-example to anyone who 
believes that municipal authorities, unlike private owners, will 
always internalize public health externalities associated with water 
delivery. Chapter Nine sums up by calling on cliometricians to focus 
their attention on inorganic toxins of which lead is but one, albeit 
telling, example.

_Great Lead_ has a great many virtues. It is, above all, impeccably 
researched and exceedingly well-written. Perhaps because he has spent 
so much time in a history department, Troesken is acutely aware of 
the value of the telling anecdote in attracting readers beyond the 
usual suspects. The book is also a poster child for interdisciplinary 
research, much beloved these days by deans and provosts. In 
particular, Chapter Two evinces a glowing mastery of the underlying 
science; surely Troesken knows more about water plumbism than any 
other historian alive (and probably, a good many medical doctors).

I am a trifle less enthusiastic about the econometrics, the details 
of which are reported in the technical appendices. Consider Appendix 
A, which presents cross-sectional evidence linking infant mortality 
to lead pipe use in Massachusetts cities at the turn of the twentieth 
century. Troesken rightly points out that OLS is a problem because of 
omitted variable bias, and he corrects for this with instrumental 
variables. Now, as someone who spends many sleepless nights trying to 
come up with one usable IV I am more than mildly impressed with 
Troesken's ability to generate three: a dummy for who paid for the 
service line (water company versus property owner), the number of 
water meters per one hundred miles of water mains, and a dummy for 
whether the local water company had been "municipalized" (switched 
from private to public ownership). I do not question that these 
instruments are relevant -- they predict lead use -- but to be valid 
they cannot have direct impacts on infant mortality, and this is far 
from obvious, particularly because the specification (p. 210) does 
not have a lot of control variables. Because of this I do not know 
whether one should place a lot of stock in the IV estimates, which 
are larger in magnitude but (predictably) less precise than the OLS 
estimates. I do not want to seem overly critical here because 
Troesken does include many robustness checks, and is unusually 
upfront in acknowledging data and other problems.

More philosophically, it is not at all clear to me why we need 
cliometrics linking infant mortality rates to lead pipes in the first 
place. That is because we know from Chapter Two's exhaustive coverage 
of the relevant science that lead is harmful in dosages vastly 
smaller than was characteristic of turn of the century urban water 
systems. What if Troesken had run his regressions and found "nothing" 
-- either a zero coefficient or (a la the IV's) statistical 
imprecision? Would we conclude that residents of Attleborough had 
nothing to fear from their drinking water? Not withstanding 
Troesken's (somewhat far-fetched) suggestion in Chapter Two that this 
might have been the case (for example, if residents didn't drink the 
water in sufficient quantities to cause illness), I don't think so. 
This is not to say that econometrics has no place in Troesken's "new 
environmental history" -- far from it. But rather than link lead 
pipes to infant mortality I would have liked to see a regression 
relating lead to wages or housing prices (more economics, in other 
words). In particular, if housing prices were lower (or wages higher) 
in cities with lead pipes this would cause me to raise my eyebrows at 
some of Troesken's claims about consumer ignorance in Chapter Seven. 
I would have also liked to have seen an analysis linking fertility to 
lead pipes, a pattern that Troesken hints might be historically 
relevant (and to my mind rather more interesting than the link with 
mortality) but which is not investigated formally.

Quibbles aside, _Great Lead_ is an excellent book, essential reading 
for anyone involved in demographic history, or the history of 
environmental regulation, water or otherwise.


Robert A. Margo is the editor of _Explorations in Economic History_.

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