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Science

A Century of Hair Samples Proves Leaded Gas Ban Worked (arstechnica.com) 61

Posted by msmash from the proof-is-in-the-hair dept.
Scientists at the University of Utah have analyzed nearly a century's worth of human hair samples and found that lead concentrations dropped 100-fold after the EPA began cracking down on leaded gasoline and other lead-based products in the 1970s.

The findings, published in the Proceedings of the National Academy of Sciences, drew on hair collected from Utah residents -- some preserved in family scrapbooks going back generations. Lead levels peaked between 1916 and 1969 at around 100 parts per million, fell to 10 ppm by 1990, and dropped below 1 ppm by 2024. The decline largely tracks the phase-out of leaded gasoline after President Nixon established the EPA in 1970; before the agency acted, most gasolines contained about 2 grams of lead per gallon, releasing nearly 2 pounds of lead per person into the environment each year.

The study arrives amid the Trump administration's broader push to scale back the EPA. Lead regulations have not yet been targeted, but the authors note concerns about loosened enforcement of the 2024 Lead and Copper rule on replacing old lead pipes.
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A Century of Hair Samples Proves Leaded Gas Ban Worked More

A Century of Hair Samples Proves Leaded Gas Ban Worked

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  • Interesting to note that this could explain some generational differences that would still be visible today.

    • Re: (Score:1, Funny)

      by Anonymous Coward

      Betcha MAGAs have higher lead levels.

    • There's a correlation with a drop in crime rates. The impact on IQ isn't significant, the impact on impulse control and resulting violent behavior, is.

  • jfc! don’t give trump any ideas of rolling this back!!!!!!!!!!

  • Unlikely to get lead back in gasoline (Score:4, Informative)

    by MtViewGuy ( 197597 ) on Tuesday February 03, 2026 @12:15AM (#65965704)

    Look, tetraethyl lead was a "cheap" way to get gasoline-fueled engines to run higher compression without pre-detonation (knocking) damaging the engine. The development of electronic fuel injection in the 1970's and 1980's pretty much eliminated the knocking problem by electronically adjusting the timing of spark plug ignition via knock sensors and a small computer, which meant modern gasoline-fueled engines for street-legal vehicles rarely suffer from this issue. Besides, modern refining technology makes it possible for gasoline RON octane ratings as high as 99 (circa 95 pump octane) in unleaded fuel, pretty much eliminating the need for tetraethyl lead.

    • Re:Unlikely to get lead back in gasoline (Score:4, Interesting)

      by thegarbz ( 1787294 ) on Tuesday February 03, 2026 @09:59AM (#65966334)

      Wrong assessment on the supply side. Refineries have always been capable of producing fuel to suit any RON requirement (just look at avgas). The question was how expensive it is to do so. TEL still remains the cheapest (albeit banned) way of increasing an octane rating, and thus improving margins. It's not the supply side of the equation that makes lead undesirable, the supply side simply adapted to market regulations, and fuel injection doesn't solve the knocking issue completely, it just allows engines to be performance managed. Sports cars still require high octane fuel for this reason despite using fuel injection.

      That said you still won't get lead into petrol. No one is going to invest a single dollar in the temporary insanity that is the Trump presidency. Re-introducing TEL is not the kind of project that would have a sub 3 year pay back period (which any response to the Orange Retard's policies would need to justify).

      • Except aviation gasoline still uses tetraethyl lead so gasoline-fueled aviation engines can run at much higher compression than automobile engines. Getting rid of tetraethyl lead in aviation gasoline has been a very contentious issue in recent years because many engines on General Aviation airplanes may not be able to properly run even with 99 RON unleaded gasoline.

    • The development of electronic fuel injection in the 1970's and 1980's pretty much eliminated the knocking problem by electronically adjusting the timing of spark plug ignition via knock sensors and a small computer

      No. Most vehicles didn't get knock sensors until the mid 1990s and you still had to set timing, they typically still had a distributor before then. For example my Nissan 240SX had a distributor with a 360 mark optical position sensor in it. You did the timing 100% the old fashioned way, by loosening the distributor bolts and turning it, and there was no knock sensor. It basically just had the electronic version of vacuum advance.

    • Re: (Score:3)

      by necro81 ( 917438 )

      The development of electronic fuel injection in the 1970's and 1980's pretty much eliminated the knocking problem by electronically adjusting the timing of spark plug ignition....

      Knock occurs because of physics. You can tinker with spark timing all you want, but if you compress an air-fuel mixture you can get knock. Perhaps you were thinking of fuel injection? (i.e., don't add fuel to the cylinder until the proper moment.)

      But modern gasoline still has a variety of anti-knock agents in it - MTBE and ethanol being the main ones in the US today - and all gasoline engines rely on it being there. MTBE and ethanol have their own issues, but far, far fewer than lead.

      • When the air-gasoline mixture burns normally, the flame front proceeds at a certain rate, and there is no knock. With high enough temperature and pressure, a shock wave is produced and the flame front is on that shock wave: knock. It's the difference between fire and explosion.

        Delaying (retarding) the spark allows ignition to occur later than the compression-caused peak temperature and pressure, potentially preventing or reducing the shock wave. That's the physics.

        Granted, Diesel engines have no spark plugs

    • Re: (Score:3)

      by tlhIngan ( 30335 )

      Incorrect.

      You can't have lead in gas nowadays because of several reasons. First, catalytic converters being mandatory - leaded gas poisons the catalyst and stops it from working. It's why cars started requiring unleaded gas - they equipped themselves with catalytic converters and they are required to use unleaded only.

      Second, gas has octane boosters. Unleaded gas from the 80s to the 2000s used various others. These days, the most universal one is ... ethanol. Octane is an anti-knock additive, ethanol being

      • It's why cars started requiring unleaded gas - they equipped themselves with catalytic converters and they are required to use unleaded only.

        Please, please have a source for this. Preferably a video NOT from the Transformers series.

        • The wikipedia page on catalytic converters gives an approximate timeline, and states that lead "poisons" catalytic converters. For many years in the U.S. gas pump nozzles for unleaded gas were (still are?) smaller than leaded gas nozzles, and the car gasoline inlets were sized accordingly. A leaded gasoline pump nozzle couldn't be inserted into a car meant to take only unleaded gas.

          The push for unleaded gas was partly due to environmental pressures on lead emissions and partly due to the requirements of cat

          • You missed what I was looking for. I want to know how the fricken car attached a catalytic converter to itself:

            It's why cars started requiring unleaded gas - they equipped themselves with catalytic converters

  • An interesting Cosmos episode about this.. (Score:3)

    by ndsurvivor ( 891239 ) on Tuesday February 03, 2026 @02:12AM (#65965824) Journal
    https://en.wikipedia.org/wiki/... [wikipedia.org] "The Clean Room" is the seventh episode of the American documentary television series Cosmos: A Spacetime Odyssey. It premiered on April 20, 2014, on Fox and aired on April 21, 2014, on National Geographic Channel. The episode explores the methods and processes used to measure the age of the Earth. The episode also pays tribute to geochemist Clair Patterson (voiced by Richard Gere) in his quest to remove the neurotoxin lead, from gasoline.[1] The episode's title alludes to Patterson's attempts in sterilizing his lab after realizing that the inconsistent results in his experiments were due to lead contamination.

  • WTF does this have to do with it? (Score:1, Insightful)

    by Anonymous Coward
    "The study arrives amid the Trump administration's broader push to scale back the EPA."

    Subtile bias alert - Orenge man bad, he is going to put lead in the water next... JFC - you retards need to get a grip. The propganda is not working any more. Trump is an ass-clown, just like biden, obama, clinton, and bush. WAKE THE FUCK UP. You are being played...

    • Re:WTF does this have to do with it? (Score:4, Insightful)

      by Anonymous Coward on Tuesday February 03, 2026 @03:39AM (#65965906)
      At this point, anyone who suggests that Trump is the same as any president before him must still be huffing leaded gas, in between eating lead paint chips. There is no fucking way that any president in the recent past, going back to Eisenhower, comes close to the level of malfeasance that Trump does. One example: name one other president that proposed suing the FTC for a personal cash payout. This is an unconscionable conflict of interest, since Trump can force the agencies in question to "settle" and still walk away with truckloads of money. If any other president even hinted as much as this, it would be a massive scandal, and likely impeachment.

      Yes, motherfucker, orange man is bad. That doesn't even touch on the child raping, or creeping fascism, among other things.

      • Re:WTF does this have to do with it? (Score:4, Informative)

        by gtall ( 79522 ) on Tuesday February 03, 2026 @08:55AM (#65966240)

        That asshole is suing his own, our own, IRS for $10 Billion. He won't get all that but he may get a payout. And who is going to defend the IRS? We have no Justice Department. The sycophants running the joint are not going to put up a fight. That is the alleged president trying steal $10 Billion from the gov. itself. I suppose that cuts out the middle men he's been using so far.

    • Things that weren't possible before Trump are now possible, especially his second term. You only have to check the news once or twice in the past year to see that.

    • Not a damn thing. (Score:2, Insightful)

      by sabbede ( 2678435 )
      The authors just couldn't resist inserting their irrelevant political opinion. A non-scientific slip-up that calls their careers into question.

    • Re: (Score:2, Insightful)

      by thegarbz ( 1787294 )

      What does a study about lead content in people have to do with Trumps policies that specifically scale back the regulatory power of the agency responsible for reducing lead content in people?

      Is that the question you are asking? Did you huff a bit too much lead in your youth?

  • At least the Biden era ban on lead pipes. Lobbyists are working pretty hard.
  • PUN INTENDED! But anyway, this whole lead debacle is scientific proof that boomers are about 9 IQ points stupider on average than us 90's kids. I am going to cite this study quite a bit.

  • The article mentions leaded gasoline, lead paint, and lead plumbing. We've phased out or are phasing out all three.

    I wonder which one had the largest impact? I have my assumptions but honestly, have no idea of the magnitudes of each. I do know that modern latex paints kinda suck compared to oil based leaded paints from a finish perspective so I'd like to know what we get for the reduced quality.

    I don't see any particular advantage to lead versus copper, iron, or PEX plumbing. Maybe there was a cost differen

    • Lead pipe is somewhat of a historical legacy. I think is was used because it was more malleable than other options, more resistant to corrosion than iron pipes, and cheaper than copper. Today the best option for indoor plumbing is probably plastic because of price and some tolerance of freezing, although copper and stainless steel have their places.

  • This might provide additional evidence for/against the thesis of the famous Rolling Stone article ("Criminal Element") by the late, great Kevin Drum, connecting crime to lead.

    All that Drum had was the decline in crime after lead was removed; thing was, the lead levels and crime rates showed correlations down to state, county, and neighbourhood stats.

    If we could also correlate with lead levels right in the residents, it would support the thesis, which still strikes many as too simplistic, crime being complic

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