Ancient Romans knew that lead water pipes were unhealthy and so they preferred terracotta pipes. It's hard to imagine why the U.S. ever had a single lead water pipe, let alone huge numbers of them.
Updated with a reference for the downvoters:
Sheets of lead were used to line Roman aqueducts (as was cement) and lead pipes to convey water. But lead also was known to be unwholesome and, for that reason, pipes made of clay were preferred—as Vitruvius, who wrote during the time of Augustus, explains.
"Water conducted through earthen pipes is more wholesome than that through lead; indeed that conveyed in lead must be injurious, because from it white lead [ceruse or lead carbonate, PbCO3] is obtained, and this is said to be injurious to the human system. Hence, if what is generated from it is pernicious, there can be no doubt that itself cannot be a wholesome body. This may be verified by observing the workers in lead, who are of a pallid colour; for in casting lead, the fumes from it fixing on the different members, and daily burning them, destroy the vigour of the blood; water should therefore on no account be conducted in leaden pipes if we are desirous that it should be wholesome. That the flavour of that conveyed in earthen pipes is better, is shewn at our daily meals, for all those whose tables are furnished with silver vessels, nevertheless use those made of earth, from the purity of the flavour being preserved in them" (VIII.6.10-11).
>Ancient Romans knew that lead water pipes were unhealthy and so they preferred terracotta pipes.
Do you have a source for this? At the same time, they used lead acetate to sweeten wine and food, which is way more dangerous. If they made the weaker connection between health and water pipes, they should have been able to connect health and this as well.
Read Vitrivius's De Architectura, specifically the part on building aqueducts. It's basically a manual for "So the Emperor told you to build a city from scratch…"
As a random aside, he also includes a proof that the water level mechanism he prefers works even though the Earth is a (roughly) spherical object and not a flat plane.
For when lead is smelted in casting the fumes from it settle upon their members and day after day burn out and take away all the virtues of the blood from their limbs Hence water ought by no means to be conducted in lead pipes if we want to have it wholesome That the taste is better when it comes from clay pipes may be proved by everyday life for though our tables are loaded with silver vessels yet everybody uses earthenware for the sake of purity of taste.
Yeah and they knew that was bad too. Probably if they had a good way of testing for lead acetate, they'd probably have thrown the occasional wine merchant to the lions.
I have a copy of De re Metallica[1] it has a whole chapter on stuff like this and that's 1500's Europe. Lead is kinda tricky since it tends to get passivized most of the time by sulfate and phosphate. Except when it doesn't and then it's insidiously bad.
Hoover was a pretty amazing man and a pretty miserable president. A mining engineer who made his pile working in China. He claimed he was literally first Stanford University student (he showed up days early when the college first opened and he stayed in the dorms by himself.)
He and his wife (who was also a geologist) were fluent in Chinese and would speak in it if they wanted privacy.
He became known for international humanitarian missions during and after the first world war. He became a national figure by directing flood relief operations during the 1927 Mississippi Flood, which catapulted him into the White House a year later.
He was a much better humanitarian than he was a president. And pretty good geologist and linguist too.
He was also chosen to tour and report on post-Second World War Germany due to his experience from similar humanitarian missions he undertook in Europe in the aftermath of the First World War.
Does anyone think that it's possible that there will be another career engineer as POTUS? I've heard that there remains a sort of stigma to such a thing, perhaps in part due to the Hoover administration.
Not only that, up to the late 20th century many products other than pipes contained lead. Lead paint, leaded gasoline, etc. The jury was out on lead in everyday use until quite recently.
I doubt the poisonous nature of lead was well known when these cities were built.
Most homes built before 1960 contain heavily leaded paint[0]. My assertion isn't that lead wasn't believed to be dangerous, rather that no one saw it as "seriously" dangerous.
> In the July 1904 edition of its monthly publication, Sherwin-Williams reported the dangers of paint containing lead, noting that a French expert had deemed lead paint "poisonous in a large degree, both for the workmen and for the inhabitants of a house painted with lead colors."
"Poisonous in a large degree" seems pretty serious to me.
People were regularly dropping dead due to lead poisoning in factories by the turn of the century, and it looks like lead was recognized as being capable of doing significant, though hard-to-recognize, harm:
"Although plumbism is usually easy to diagnose, lead occasionally induces obscure affections of the nervous system, the cause and true nature of which are not always easily recognized. As a cause of poverty, too, its influence is not sufficiently known nor the role it may be playing in the physical degeneracy of the race."
Lead paint looks to have been largely banned in Europe in favor of zinc-based paint by 1911; it was clearly viewed as a public health threat, not least by housepainters themselves, who were dying of lead poisoning (see the table on page 25).
Most houses in the U.S. built prior to a few decades ago have lead paint and many have asbestos. Then there's the whole leaded gasoline fiasco.
The world has known of the danger of lead and many other dangerous substances, but often still chooses to use the dangerous substance.
Sometimes it's because there weren't alternative substances that could do what needed to be done. Sometimes it was just a matter of expense. Sometimes it's because the dangerous substance was supposed to be used in a safe fashion, however reality proved the safe fashion to be overly optimistic.
Course, then there are cases like the leaded gasoline that should be considered one of the greatest crimes of all time.
>Course, then there are cases like the leaded gasoline that should be considered one of the greatest crimes of all time.
And the man who was responsible for this was also responsible for CFCs. "He had more impact on the atmosphere than any other single organism in Earth's history."
On October 30, 1924, Midgley participated in a press conference to demonstrate the apparent safety of TEL. In this demonstration, he poured TEL over his hands, then placed a bottle of the chemical under his nose and inhaled its vapor for sixty seconds, declaring that he could do this every day without succumbing to any problems whatsoever.[5][8] However, the State of New Jersey ordered the Bayway plant to be closed a few days later, and Jersey Standard was forbidden to manufacture TEL there again without state permission. Midgley would later have to take leave of absence from work after being diagnosed with lead poisoning.
I believe no truer words have been spoken than the opening of the section on Midgley in that article -
"Thomas Midgley Jr. Tried Really Hard to Destroy the World"
The man was the template for a Mad Scientist and the closest thing to a super villain there has been. It's a bit of poetic justice he died as a result of one of his own contraptions.
There is an episode of American Experience that has a part on the introduction of leaded gasoline that covers it better than the Cracked article, it's just not as funny.
Yep, most of the small piston-engine aircraft are designed to run on 100-octane fuel. The only practical way to get the octane that high is leaded gasoline. However, the lead levels are lower than they used to be (avgas is typically 100LL for "low-lead"). Also, general aviation only consumes about 0.1% of the transportation fuel supply, so we're talking about a minuscule fraction of the fuel consumed.
More modern aircraft can often get by with 94-octane premium unleaded. However, they cannot tolerate ethanol in their fuel, and due to congressional mandates for ethanol blends it's become increasingly difficult and expensive to source ethanol-free premium gasoline. Paradoxically, this pushes general aviation back to 100LL, which can easily be sourced without ethanol.
Modern aircraft also have a trend towards diesel engines (often adapted from automotive diesels) that can be run on Jet A-1 fuel. These are actually very promising because they have good performance-to-fuel economy. See the Diamond DA62 for an example.
The root problem is that the general aviation fleet turns over incredibly slowly due to intensive maintenance requirements imposed by the FAA (eg annual total overhauls). It's pretty normal for your average single-engine aircraft to reach a lifespan of 40-50 years, and there's still plenty of aircraft that are pushing 70 or 80 years old.
As such it's very difficult to achieve a phase-out of a fuel type within timeframes that people consider reasonable. Like I said, the shift towards 94-octane premium unleaded and diesels is already happening, but it will probably take another 20-30 years for the fleet to naturally rotate to engines that support alternative fuels.
FAA oversight requirements (parts sourcing and mechanic labor) make everything airplane-related insanely expensive. You could mandate engine replacements, but this would be so expensive it would basically total 50% of the general-aviation fleet in an instant. At the end of the day we're talking about <0.1% of the transportation fuel supply so it's just not that big a deal.
I'm not in a panic about the lead in aviation fuel, but the relatively tiny amount of fuel used isn't really the thing you want to consider, you want to look at the absolute harm done by the use.
I do realize that in this case the harm is likely extremely difficult to even estimate.
The total US lead emission from general aviation is about 500 tons per year, which in 2002 was about 45% of total lead emissions (which is higher than I'd thought). One caveat is that is an upper-bound number, not all 100LL fuel has the maximum quantity of lead additive. It's fine if it reaches 100 octane on a smaller amount. It's also a historic number: the industry is shifting towards 100 Very Low Lead type with a 20% lower TEL limit. And general aviation has been in decline for about two decades due to spiralling cost. So that number is probably on the high side.
Most of the fleet (~70%) would be OK switching to 94-octane unleaded. The biggest problem is that Congress/states have made it extremely difficult to source this type of fuel, because the overwhelming majority of fuel is produced for automotive usage. Ethanol and other mandated additive blends are unacceptable for aviation usage, and we're talking about 0.1% of the fuel market. Congress/states have put up barriers that impede a shift and they need to do something to help that overcome those barriers, not just ban 100LL.
Also, due to the nature of general aviation this is a very distributed problem. Most general aviation occurs at relatively small airfields/airstrips and there's many factors that make it difficult for GA pilots to use large airports (limited access to those airspace types, high traffic levels from commercial aviation, high ramp/fuel fees designed to discourage refueling, etc). So you've got to get 92UL available at a large number of small sites. Most small airports will carry at most two types of fuel, 100LL and Jet A1, and many will only carry 100LL. Most airports are running on super thin margins and adding 92UL would mean not carrying 100LL.
That leaves the 30% of aircraft that can't use 92UL pretty high-and-dry. Some can be modified, some will need engine replacements, a lot will be out of luck. Unfortunately they are likely concentrated at the affordable end of the fleet, and that translates into more cost increases in a sector that's already dying due to a cost spiral.
General aviation is a feeder for commercial aviation, and that's going to become an even tougher and more expensive path to follow. Going commercial requires a large number of flight hours which are typically accrued by getting an instructor license and training casual pilots - so cost increases that reduce casual pilot time percolate very directly into a reduced supply of commercial-eligible pilots. The only other route is ex-military pilots, or paying >$100k through a university (which is not commercially viable due to the ~$20k average salary of an entry-level regional pilot).
General aviation is also a neat cultural touchstone that I am sad to see shrivelling into nothing :(
Re being a commercial feeder, that's like lots of things, if individuals start refusing to bear the cost of obtaining hours, airlines will be required to make changes. They might increase pay for pilots, lobby for changes to the licensing process or provide alternative ways to get those flying hours (I'm not sure how you subsidize hours without perverse incentives, but I guess you could protect investment using loans that had forgiveness for service).
You've pointed out some purposes that GA fulfills, but you haven't addressed what harm those lead emissions are actually doing. It could be minimal. Or, it could be pretty severe when you look at the aggregate impact. At a structural, societal level, poisoning people to avoid higher direct costs for air transport is likely not a good trade-off, so it is necessary to look at both sides of it.
A few nits I'd pick. Even though 70% of the fleet could burn 94UL, that represents well under half of the gallons burned. Turbocharged engines (often in twin engine airplanes) fly far more hours than the average 7.5:1 compression piston single. Yes, flight school aircraft on the low end fly a lot, but most piston singles average under 75 hours per year and often at 8-9 gph. Turbo singles, IO550s (Cirrus and Bonanza), and turbo or IO550 twins are typically burning 1.5x that per engine and flying 2-3x the hours.
I think most of the engines that can't be easily modified to run on 94UL are concentrated on the expensive end of the fleet. Most 182s/172s/Cherokees/G-cats, etc can either already run today under the Petersen STC or could be easily modified. It's the Bonanza, Cirrus, Golden Eagle, P-Navajo, etc that need 100LL (or GAMI or similar) and can't run on 94UL. Those tend to be way more expensive than the lower end of the fleet.
Most (>95% for sure) small planes use leaded fuels. Many (probably three-quarters of the fleet, but probably less than a quarter of the gallons of avgas burned) of those planes could readily use ethanol-free unleaded avgas without significant modification.
The high powered planes are the ones that also fly the most hours and burn the most per hour, which is why the bias is so different by gallons rather than fleet size. Many of those perform critical functions (mail/parcel delivery, food delivery, remote people transport, pipeline patrol, traffic reporting, pilot training) and there is no certified replacement fuel available. The logistics are such that if an airport business has to carry leaded fuel for 75% of your avgas sales and the other 25% can also burn 100LL, there's little incentive to install duplicate tanks, fuel trucks, etc for zero additional sales of fuel.
There are promising unleaded fuels in testing (not derived from unleaded autogas) that the high-compression and turbo-charged aircraft can run without modification. The approval process via the FAA is very slow-moving, expensive, and risk-averse. (in many cases for very good reason, but it's still a significant barrier in that I cannot legally burn the prototype fuels, nor any unleaded fuels, in my aircraft).
I would switch to the GAMI fuel tomorrow if it was available for sale. For the small amount I burn per year (estimated 1500-2000 gallons), even an increase of $2/gallon would be no barrier for my adoption and the likely increase vs today is lower than that. There are other fuels also under consideration or certification testing, some of which require airframe or engine modifications, others of which are also "drop-in" replacements.
TEL really is fairly magical in terms of improving knock and detonation margins in highly stressed engines, so it's no surprise that its adoption became so widespread after World War II. The transition away from TEL is not a trivial exercise, which is why it's "taking so long" to make progress on this. The world needs a physically and chemically workable fuel, but also needs an economically workable fuel.
> It's hard to imagine why the U.S. ever had a single lead water pipe, let alone huge numbers of them.
Lead has some advantages. Its melting point is low, so it's easy to weld. It doesn't corrode quickly, so pipes last a long time. And it's malleable, so pipes don't break when soil and foundation shift. But yes, it's very poisonous, so the advantages are moot for drinking water.
For corrosive waste plumbing, on the other hand, it can be a good choice. It even tolerates HF, which glass doesn't. Glass is sexier, however.
>It's hard to imagine why the U.S. ever had a single lead water pipe, let alone huge numbers of them.
I always supposed that that's where the word 'plumber' came from, or 'loodgieter' (lead caster, Dutch). Both words strongly refer to lead. Growing up in Holland in the early 80's our house had lead pipes. When I bought my first house in 2003 it too still had a lead water main. I drank a lot of that water, tap water over here has the same purity (basically actually is the same) as mineral water, with no side effects.
Updated with a reference for the downvoters:
Sheets of lead were used to line Roman aqueducts (as was cement) and lead pipes to convey water. But lead also was known to be unwholesome and, for that reason, pipes made of clay were preferred—as Vitruvius, who wrote during the time of Augustus, explains.
"Water conducted through earthen pipes is more wholesome than that through lead; indeed that conveyed in lead must be injurious, because from it white lead [ceruse or lead carbonate, PbCO3] is obtained, and this is said to be injurious to the human system. Hence, if what is generated from it is pernicious, there can be no doubt that itself cannot be a wholesome body. This may be verified by observing the workers in lead, who are of a pallid colour; for in casting lead, the fumes from it fixing on the different members, and daily burning them, destroy the vigour of the blood; water should therefore on no account be conducted in leaden pipes if we are desirous that it should be wholesome. That the flavour of that conveyed in earthen pipes is better, is shewn at our daily meals, for all those whose tables are furnished with silver vessels, nevertheless use those made of earth, from the purity of the flavour being preserved in them" (VIII.6.10-11).
http://penelope.uchicago.edu/~grout/encyclopaedia_romana/win...