Zinc Fever: A Look At The Risks Of Working With Hot Metal

For as raucous as things can get in the comments section of Hackaday articles, we really love the give and take that happens there. Our readers have an astonishing breadth of backgrounds and experiences, and the fact that everyone so readily shares those experiences and the strongly held opinions that they engender is what makes this community so strong and so useful.

But with so many opinions and experiences being shared, it’s sometimes hard to cut through to the essential truth of an issue. This is particularly true where health and safety are at issue, a topic where it’s easy to get bogged down by an accumulation of anecdotes that mask the underlying biology. Case in point: I recently covered a shop-built tool cabinet build and made an off-hand remark about the inadvisability of welding zinc-plated drawer slides, having heard about the dangers of inhaling zinc fumes once upon a time. That led to a discussion in the comments section on both sides of the issue that left the risks of zinc-fume inhalation somewhat unclear.

To correct this, I decided to take a close look at the risks involved with welding and working zinc. As a welding wannabe, I’m keenly interested in anything that helps me not die in the shop, and as a biology geek, I’m also fascinated by the molecular mechanisms of diseases. I’ll explore both of these topics as we look at the dreaded  “zinc fever” and how to avoid it.

Flu-Like Symptoms

One of the first things you’ll notice if you research zinc fever is how hard it is to find useful information. Googling “zinc fever” will get you a load of articles about using zinc supplements to stave off viral infections, not to mention other medically dubious uses for zinc. That’s partly thanks to living in these pandemic times, but also shows the unusually high noise floor that attends most searches for actionable medical information, as opposed to anecdotes.

Thankfully, though, I was able to dig deep enough to discover that what’s called zinc fever is an actual illness that has been well-described in the medical literature since the mid-1800s. It goes by a wide range of names, from the wonderfully medieval-sounding “brass founder’s ague” to “the galvie flu”, all of which reflect the fact that this is largely an occupational hazard of the metalworking trades. The illnesses all fall under the broad category of “metal fume fever” or MFF.

The metal most strongly associated with MFF is zinc, either alone or in alloy with other metals — hence the association with brass, an alloy mainly composed of copper and zinc. Other metals that can cause the illness pretty much run the gamut of commonly worked metals; the most common culprits after zinc are chromium, cadmium, and copper.

Metal fume fever typically presents as a sudden onset of classic flu-like symptoms — fever, headache, muscle and joint aches, fatigue, nausea, and violent chills. Symptoms usually begin within a few hours of exposure to metal fumes, either via welding, grinding, or foundry operations. Diagnosis is typically made based on the history, as opposed to any blood tests or other diagnostics; basically, someone who presents to an emergency room with flu-like symptoms who reports welding within the last day or so will get a presumptive diagnosis of MFF, after ruling out other possible causes.

In almost every case study and review on MFF that I could find, the course of the illness was characterized as “self-limiting”. This is medical shorthand for “it’ll go away in a couple of days,” and indeed, for most metalworkers that’s clearly the case. While some people who’ve gotten MFF report a week or so to get back to feeling normal, most are up and around again after just a few days of feeling really, really crappy.

Going Too Far

Jim “Paw-Paw” Wilson. Source: Anvilfire.com

Most, but not all: take the extreme case of Jim “Paw-Paw” Wilson, a blacksmith of some renown in the smithing community. Back in 2005, when Jim was 65, he was building a stock rack from surplus galvanized pipe. Knowing the dangers of zinc fumes, Jim attempted to burn the coating off some pipe fittings in a gas-fueled forge. He apparently charged the forge with too many fittings at once, which filled the shop with billows of thick, white zinc oxide smoke. The smoke was so thick that it left deposits of zinc oxide 1/16″ (1.5 mm) thick on the inside of the forge.

As he probably had multiple times in his metalworking career, Jim took ill with the classic symptoms of MFF shortly after that forge session. He felt well enough within a few days to take a trip, but a week after the exposure he came down with bilateral pneumonia, which killed him the next week. While it’s true that Jim suffered from emphysema before the forge incident, and that probably contributed to the outcome, the fact remains that he likely would not have gotten the pneumonia that killed him had he not tried to burn off those fittings.

Although Jim’s case was an extreme one, both in terms of the amount of zinc oxide fumes produced and the victim’s underlying medical issues, it does illustrate the point that MFF can be dangerous under the right conditions. However, the risk of dying from MFF seems to be quite low. I couldn’t find much information about the epidemiology of the illness except that there are an estimated 1,500 to 2,500 cases per year in the United States, about 700 of which were reported to poison control and a third of which required medical treatment1. It’s not clear from this review whether any of these cases resulted in death, but it’s probably safe to assume that the authors would have mentioned any deaths that had occurred.

Speaking of poison control, an interesting aspect of MFF was revealed by a 2012 review of data from poison control in Victoria, Australia2. They plotted the number of calls to poison control against the day of the week that the incident occurred, and found that Monday was by far the most likely time for someone to come down with MFF. This goes along with one of the alternate names for MFF, “Monday morning fever”, and may have to do with a certain degree of tolerance that the body builds up with extended exposure to small amounts of metal fumes. The thinking is that after a weekend away from the shop, the body’s ability to deal with the zinc toxin has decreased, making it more likely to cause symptoms after a weekend away from the shop.

Monday is the most common day for MFF. Source: Australian Family Physician 2012; 41: 141-3

How It Works

This is all well and good, but what about the meat of the problem: how do metal fumes cause flu-like symptoms? Put simply, we just don’t know. The mechanism doesn’t appear to be well studied, possibly due to the fact that the illness is generally self-limiting and non-fatal. But it’s likely that what causes the symptoms experienced during a legitimate case of the flu — or, as we’ve learned the last year, a coronavirus such as SARS-CoV-2 — also causes the symptoms of MFF. So the blame falls on the human immune system, with activation of white blood cells called neutrophils; the release of cytokines, signaling chemicals related to inflammation responses; and formation of oxygen radicals. These form the biochemical brew that makes you feel so bad during the flu, and it’s thought that zinc oxide and the other metal vapors associated with MFF somehow trigger their release too.

A plant metallothionein, which is similar to mammalian MTs. The sulfur-rich cysteine residues (yellow) form coordination centers that bind to metallic ions (purple) and scavenge them from cells. Source: Thomas Shafee, CC BY 4.0

Another clue as to how MFF happens is revealed by looking at that “Monday morning fever” aspect of the illness3. The ability to develop tolerance to metal fumes over time is thought to be related to the expression of metallothioneins (MTs), which are sulfur-rich proteins that are specialized for binding metal ions in the body. A single human MT molecule can scavenge up to seven zinc ions, sequestering them and preventing them from doing whatever they do to activate the immune system. Small amounts of metal ions are thought to stimulate MT expression, which tracks with building up a tolerance over the workweek. In the absence of stimulus, though, like over a weekend away from the shop, expression of MTs is down-regulated, meaning the hapless welder who gets a big dose of zinc on Monday likely has a reduced ability to deal with the threat.

And because someone is sure to mention it in the comments, we’ll point out that old-school welders swear by the drinking of copious quantities of milk before welding anything with zinc in it to stave off the symptoms of MFF. There are plenty of anecdotes out there about how well this works, and there’s speculation that the calcium in the milk somehow blocks or competes with the zinc ions. But given that most recommendations are for drinking four or more liters of milk, and that it has to be done before welding starts, it’s probably not going to be practical for most people as a prophylactic method.

So, what’s the take-home message on metal fume fever? I think, first and foremost, that welders need to realize that it’s a real illness and not just some old wives tale. From all accounts, the illness is self-limiting and temporary in nature, but unless you have underlying medical conditions, it doesn’t seem likely to kill you. Given how debilitating flu-like symptoms can be, though, I’m not sure why anyone would even flirt with something that will make you feel like that, even if only for a couple of days. If I absolutely had to weld something galvanized, I’d make sure to do it with some sort of positive-pressure respirator, with fume extraction, or even outdoors to keep those noxious fumes away. Better to be overly cautious than to be laid up for a couple of days with symptoms that could easily be confused for something else, especially in this day and age.

References:

  1. Ahsan SA, Lackovic M, Katner A, Palmero C. Metal Fume Fever: A Review of the Literature and cases Reported to the Louisiana Poison control center. J. of the LA State Med Soc 2009;161:348-351.
  2. Wong A, Greene S, Robinson J. Metal fume fever: A case review of calls made to the Victorian Poisons Information Centre. Australian Family Physician 2012; 41:141-143.

69 thoughts on “Zinc Fever: A Look At The Risks Of Working With Hot Metal

  1. Good write-up, thanks! When I weld galvanized stuff, I try to grind off the galvanizing a couple of inches back from the weld area and always do it outside. Grinding the galvanizing off is important (in addition to the health issue) because it makes for a crappy weld if you don’t.

    1. Agree about grinding it away, it hisses and spits otherwise, 20 years ago I spent a while metal spraying zinc, the flu thing is real but short lived, at least for me, it was a known possibility, even with PPE extraction and water curtain.

    2. Generally always lightly grind the surface you want to weld, both for removing things that can create nasty fumes when heated to approx weld pool temperatures, and to minimize weld contamination.
      One of the reasons I got a angry grinder that’s only fitted with a “coarse” grit flappy wheel, since that’s my designated “prep the weld sites” tool.

      1. Yeah and please wear a mask for that too!
        I still wonder why some people don’t wear proper PPE. Like… does it not look cool or something?

        My dad in his late 60s worked in a very loud environment for 45 years. Lost >80% of his hearing. It was just not a thing to wear safety glasses and hearing protection back then.

        I don’t want neither lung cancer nor hearing loss nor want I to be blind damn!

        1. To some extent its the comfort factor – goggles, mask and ear defenders are a pain to put on, rarely comfortable (and in my experience rarely actually function properly if you are using more than one of them – rapid fogging of your eyesight perhaps isn’t even safer than breathing in a little dust, its certainly harder to work with. Ear defenders rarely seal well if you have any goggle/mask straps over the ears area as well. Worth noting I have a hard enough time finding head mounted PPE that properly accommodates my rather larger than average head anyway, so my experiences may be somewhat tainted by that)

          PPE is important, but its also worth considering just how needed it is when it majorly discomforts/distracts, and if using it is always actually safer.

          Like the gloves around rotating tools argument – certainly got merit, gloves could cause grabbing problems, but under the right circumstances the impossibility of keeping a good grip without means they could still be far more beneficial than than not.
          Ear defenders don’t just reduce the noise of the tool you are using, but reduce you awareness of surrounding activity – so again could put you at greater risk in some environments.

          For me at least it is being aware of the risks and managing them that is important, not wearing full hazmat encounter suits that actively protect, while making actually get the job done almost impossible… Life only has one destination, we will all get there in the end, and it does no good trying to live forever. What does make sense to me is taking “risks” only once you have educated yourself as to the severity so however long you have on this planet is as enjoyable and productive as you can be..

          1. > Ear defenders don’t just reduce the noise of the tool you are using, but reduce you awareness of surrounding activity – so again could put you at greater risk in some environments.

            Years ago I visited Broken Hill in Australia and did a mine tour.
            Down in the depths the guide was explaining the drilling process before explosive insertion.
            Quote: “We don’t wear ear protectors as the rock above can crack and fall on you so hearing that crack is life saving”.

        2. For zinc I’ve been told the activated charcoal vfilters will catch it, not surebif thats true, but i weld galvanized outside always because the wind certainly catches it. Also heard pseudoephedrine helps if you get it. The mechanism by which zinc aids fighting off infection might be a hint as to the cause. We always have some baddies floating around, if suddenly you gibe your immune system what it needs to do battle, perhaps it kills some off, and then there are fewer baddies left until you give it the weekend off.

    3. The phosgene thing with welding is a real hazard, but not zinc related. What can cause that is using chlorinated brake cleaner to prep a weld site. The UV exposure can break down the chlorinated cleaner and release some very nasty crap.

    4. Good write up of what this article covers. Do not treat me as an expert. Find expert help.

      The amount of fume is dependent on temperature. Welding is hot. Zinc boils (turns to vapor) at 907˚C (1665˚F). Once it evaporates in air it immediately oxidizes and becomes fume, a solid, in this case zinc oxide.
      At melting the vapor pressure is very low and the amount of fume is small. This reduces the amount of protection needed by several orders of magnitude.
      The low aluminum alloys melt at an even lower temperature than zinc alone, consequently produce even less fume.

      You still need care and protection from fume. As I understand it, because of the size of fume particles most filtering masks do a poor job of removing fume.

  2. Nice write up on the subject.

    MFF is also an issue when working with ceramics, as I learned after a close call in a research context. While a major culprit in MFF is Zn, exposure to other metals can also occur in the same way. This is of particular concern if you have high heat and anything with the heavier metals involved. So it’s wise to make sure you know the elements you’re exposed to and not just assume it will go away with no long term effects. It’s also a good idea to make sure any ER doc or GP treating you knows about such exposure.

  3. You might want to look at the AWS (American Welding Society) for a LOT of information, starting with FACT-25_2014.PDF — Metal Fume Fever

    OSHA 1910 also has a lot to say, as does OSHA 1926 (subpart J, in particular). Even if you are in your garage, these provide a good guide to the risks and how to control them.

    Also be aware the zinc, though annoying, is, as noted, relatively low long term risk. Other metals are NOT. Cadmium is both a cumulative and acute hazard, enough so that we need an action plan, chromium is also both an acute and a cumulative concern, though the Cr-VI species, being a pretty good carcinogen, gets the most attention, copper is pretty much the poster case in the dose is the poison, and so on.

    Don’t mess with metal fumes. Ventilation is your friend.

    Oh, by the way. The milk thing has no evidence to support it.

    1. Thanks for that. I always go with “don’t use your lungs as a filter” but when I read cadmium and chromium (with their relatively low toxicity) I get worried people aren’t taking the risks of metalworking seriously.

      Nice accurate documents on mitigation help prevent stupidity, hopefully.

  4. Reading through the MSDS for some of the Zinc-based compounds we use at work, it seem that its just a case of metal irritating lung tissue, causing a bit of inflammation, and reduction in the rate of oxygen absorption (Producing the flu-like symptoms and the fatigue). The Monday thing might be more of an affect of people noticing the symptoms rather than the actual onset of symptoms. But there is just too little data to make any conclusion from it, 90 is a poor sample size.

    But really, if you are working with something that produces fumes, wear a respirator.

  5. Let’s not forget about good ol’ Hexavalent Chromium see link below.
    http://www.osha.gov/hexavalent-chromium

    I think it is also important to talk about risk mitigation techniques such as fume extractors and PPE.
    A few years ago the organization I work for mandated all welders use Power Air Purifying Respirator(PAPR) equipped welding helmets for all materials, all processes. We weld a lot of stainless and high chromium steel. The PAPR is very comfortable and makes welding much more pleasant. It mitigates noxious fume inhalation and as an added bonus blows a nice cool breeze of filtered air over you face.
    I have subsequently purchased my own for use in my personal shop. They are a little pricey for the occasional home shop welder. I have noticed that the price has come down significantly over the last 10 years, as they’re being adopted by more companies as part of their Hex-Cro mitigation plan.

    1. Very good point on PAPRs. Best part for PAPR: Fit test is not required for many types used in general industry, as they are not intended to form a seal, but instead maintain positive pressure. (It is still required, blower off, for seal-forming facepieces)

      The reduced costs due to using the PAPR in industry more than make up for the unit cost of the unit (relative to a conventional respirator). Relative to a conventional unit, there is reduced training burden, no need for fit test, generally easier maintenance, greater compliance in use, better productivity (operator comfort is a BIG productivity boost, and reduced downtime for adjustment, repair, “comfort breaks”, and so on), lower record keeping burden. Since the intake can be removed from the face by a meter or more, it can be worn so that it is further from the fume source, reducing the filter burden. When practicable, I push that they should replace conventional types.

      Hardest part: keeping the batteries charged. Tracking filter elements (types and inventory) is about comparable to conventional units.

  6. I’d think that drinking a gallon of milk would help, but only because you’d be too busy in vomiting up all that milk to ever start welding, and thereby limiting your exposure significantly…

  7. Hmm, no mention of it giving you the mother of all sore throats. It feels like you snorted sulphuric acid and it happens very quickly. I got the T shirt on that one several times.

    1. First and last time I welded the exhaust on a car without proper ventilation was when it ironically was with galvanized piping.
      Felt like how a chsinsmoker would without the nicotine to dull the pain.

  8. I’ve done a lot of hobby level blacksmithing and welding, and given myself a couple of cases of zinc fever. Never doubted it was a real thing, although I tended to be rather dismissive of it as a serious issue. I think hearing about the blacksmith that died was a big wake up call for me and a lot of other hobby blacksmiths.

    Now, when I have to work with galvanized metal, I dip it in muriatic acid till the zinc is etched down to bare steel, then neutralize with baking soda solution, so it doesn’t rust like crazy as it dries. It still rusts a bit, but not nearly as bad as if left to dry with the acid still on it. Haven’t had a case of the zinc fever since.

    1. Yeah, that’s what I showed up to suggest. Toilet bowl cleaner often is hydrochloric acid. You can dip the steel in that until the fast foaming stops as all the zinc is gone, and all that’s left is the steel, and, yeah, wipe down with something basic to reduce rust. For TIG I only need to strip back about 3cm. For torch welding I’d strip all the zinc off.

      1. I had to weld a galvanized pipe and dunked the end in vinegar overnight. Worked fine and no rust. 2nd thing I ever welded, and if it wasn’t for these auto-darkening helmets I would have never even tried.

  9. Several things worth mentioning. Zinc is a necessary nutrient, therefore it is not likely a poison. Zinc is always found in combination with Cadmium (a biologically toxic metal). My personal experience with metal fume illness was not singularly the welding of galvanized steel — but also the vapors from using silver solder, which contains 24% cadmium. Therefore it is my conjecture, based upon the toxic effects from silver solder being identical to welding galvanized steel, that it is likely the cadmium contamination in zinc that causes the actual illness and not zinc itself. Of course since metal fume illness is not lethal, there have been few case studies performed.

    The label on the sliver solder states: Cadmium-containing fumes are extremely toxic. Acute overexposure can cause chemical pneumonia which may be fatal. Use only in a well ventilated area. Chronic exposure can cause lung tissue damage, kidney damage, lung cancer, prostate cancer and is known by the state of California to cause birth defects and other reproductive harm. I thought I would share this with the group, as it might be insightful.

    1. There are plenty of necessary nutrients that’ll kill you in large quantities. Not enough iodine? goiter and all sorts of problems. Too much iodine? all sorts of different problems.
      Galvanized steel is hot dipped in zinc. There’s virtually no cadmium in it: it’s just a series of zinc-iron alloys that are mostly zinc.

      1. Facts About Cadmium
        History
        Friedrich Strohmeyer, a German chemist, is credited with discovering cadmium in 1817, according to Dartmouth University, although K.S.L. Hermann and J.C.H. Roloff, German scientists, independently discovered the element in the same year. In both cases, cadmium was found in zinc oxide, which was typically used as a topical medicine at that time. Strohmeyer also found cadmium in many other zinc compounds, including several samples that were supposedly pure zinc, according to Chemicool. He estimated that cadmium made up between 0.1 and 1 percent pure zinc and in zinc compounds. http://www.livescience.com/37044-cadmium.html

        1. “before cadmium was known, it was not separated from zinc”
          it appears to be impracticable to separate cadmium completely from zinc – published in 1973
          books.google.com/books?id=qYZMAQAAMAAJ&pg=PA12

          “Excellent cut-and-paste without attribution”
          Attribution is the livescience.com URL at the bottom, as shown above.

          “If you did have cadmium poisoning, you would not be saying this.”
          NIOSH estimates that about 10% of the workers employed for two or more years in jobs exposed to cadmium would die
          http://www.cdc.gov/niosh/pgms/worknotify/cadmium.html

          “Yes, there are Cd bearing silver solders.”
          It is a low temperature alloy used in electronics. Cadmium reduces the working temperature required and has great flow properties.

          “Signs of too much zinc include” You list a number of things which do not match the symptoms welders experience, whereas Cd exposure symptoms DO match the symptoms welders experience.

          Breathing in cadmium can result in:
          Flu-like symptoms, such as body aches, chills, weakness
          http://www.winchesterhospital.org/health-library/article?id=120796

          Zinc causes nausea, vomiting, cramps, diarrhea — whereas cadmium causes flu-like symptoms, body aches, chills, weakness. Metal fume illness is described as “Flu-Like Symptoms” matching that of Cd poisoning. It’s stated right in this article (see above).

          As much as you can’t stand it for whatever reason, it appears that I actually may be on to something here. It may not be the zinc, but the contaminant cadmium as the cause. No attempt whatsoever is made to purify cheaply produced zinc used to galvanize steel in bulk. Cadmium is a trace contaminant, naturally found in pure zinc.

          It is worth noting that your behavior is not unexpected, every time I apply my higher intellect to an issue, attempting to provide a little insight for the benefit of others — I am attacked by those who have never before encountered anyone offering a new and different perspective. I am then forced to publicly humiliate the arguer, with substantiated facts supporting my position. No matter where I go or what I do, this paradox seems unavoidable. No, I am not a bot. Yes, you can learn from this moment. I test in the 99th percentile. It’s advantageous for you, to treat me as a friend.

        2. “One part of that sentence has to be wrong, Mr. 99th Percentile.”
          I was referencing the parent citation which states, “He estimated that cadmium made up between 0.1 and 1 percent pure zinc” and “it appears to be impracticable to separate cadmium completely from zinc”.

    2. Most silver solders (i.e. brazing rods used for potable water plumbing) do not contain any cadmium, but some brazing rods include cadmium to improve the flow of the hot metal into gaps, i.e. for refrigerator circuit plumbing connections.

      The liberated cadmium can cause an acute, sometimes fatal pneumonitis after one off exposures.

      Most commercially produced zinc comes from lead/zinc +/- silver +/- copper ores, which usually contain cadmium, but the very heat labile cadmium comes off at the initial sulphide ore roasting stage as fume which is collected, concentrated and from which the cadmium is subsequently extracted and refined.

      There are cases reports of metal fume fever from metals such as copper, but you would need to be doing pretty exotic processes to be exposed, i.e. tig with copper.

      1. “tig with copper” I’ve never before thought about feeding copper wire into my tig welder. Now you have me curious how effective that might be — in plumbing WELDS. :-) Actually a really interesting idea and something I may try. However copper may not be resistant enough to be used as a welding wire.

        1. The welder you feed with a wire is normally a MIG welder. For TIG welding you add the wire manually. But most often copper (alloys) are used in brazing. Not that a nice oxy-acetylene flame has much less temperature than the arc.

          1. Correct, that should say mig not tig, as tig welders use a tungsten electrode for the arc, while mig generate the arc from the feed wire. Most of us have mig welders.

        2. Tig welding copper is a lot of fun. My work in the HVAC field i’ve seen ball valves where the case halves were tig welded together to prevent leaks. Upon some further research I decided to try and tig copper. It takes alot of heat. For filler wire I just used solid core 18 gauge. One of the coolest things I tried was welding two quarter dollars together. Yes U.S. quarters are copper. I put two together faces out and welded the seam between the two. The end result was super cool and became a necklace for a numismatic friend. I also welded some copper pipe just to try it. I’ll stick to brazing as tig takes too long. I gotta say it looks cool though!

          1. Can you feed copper wire as the electrode in a mig welder? I would imagine copper lacks enough resistance for that to work. The mild steel feed wire I use is lightly copper plated, probably so arcing doesn’t take place in the handle. However using solid copper would make an interesting experiment.

    3. There is quite a different between ingesting a trace element and breathing it into your lungs. Your digestive tract processes materials much differently than your lungs which have a direct interface with your blood stream. Lots of nutrients are toxic in high concentration. Please don’t use your conjecture when OSHA and the American Welding Society have made science based recommendations.

      1. This is precisely how science works. You make an observation then say something completely radical that everyone denounces. You may even go to prison for saying it. If true, eventually everyone realizes you were right. Just ask Galileo who made the audacious clam that the earth is not the center of the solar system, and then went to prison for saying it. ;-) He was, in his time, thoroughly denounced as wrong by all the smartest people in his field and those in political power. However the evidence remained on his side and in time, he was exonerated. Unlike the wild claims of a crackpot, evidence does exist to support my theory. Remember, it only takes a tiny amount of Cd to cause metabolic disturbance. I’m not saying other metal vapors are not an issue as well, just that Cd may cause the bulk of the symptoms. I mean, we know for a fact Cd is present in cheap galvanizing zinc, at rates between 1 and 10% in concentration. Until there are a number of deaths associated with this, there will be no real research. Therefore my conjecture remains a valid possibility. History is rife with many government (id est OSHA) recommendations that they simply got wrong — such as smoking. It wasn’t until 1964 when the Surgeon General first concluded that cigarette smoking was harmful. So even smart people in positions of power, make egregious mistakes, most of the time. Every major scientific advancement historically starts with a single, lone heretical voice that the learned elders and experts promptly and resoundingly denounce. Every. Single. Time!

        1. Galileo went to jail because his defense of heliocentrism was perceived to insult the Pope-a political leader, and because the earth-centric arguments were presented as coming from the mouth of “Simplicio” which is the Italian word for simpleton. (And the Pope, a supporter of Galileo, had specifically asked Galileo to write his book presenting both arguments without advocating heliocentrism. Did the Pope do this so there could be a rational discussion about ideas? I don’t know, I wasn’t there, but it seems… rational…)

          Heliocentrism was not Galileo’s idea (Copernicus formalised the model) and the entire controversy (earth-centric vs sun-centric) occurred within the larger, decades long, context of “scientific method” vs “received wisdom” (Aristotilean) and various factions jostling for political power.

          So, Galileo went to jail for shooting off his mouth and pretending that his “big brain” protected him from the consequences of insulting people who weren’t in the 99th percentile. Which suggests that frequently used metrics of intelligence neglect certain other, rather important, facets of intelligence.

          1. Upon first blush, it appears that you might condone Democratic mob rule over the scientific method, but surely that can’t be the case. Galileo’s championing of Copernican heliocentrism was a mistake, indeed his greatest mistake, one which he was forced to renounce (lest he be burned alive for heresy). I know first hand how it feels to have great ideas dashed to the rocks by an intellectually median citizenry. But on the plus side, *I* always benefit from that which others freely reject. Studying the now widely “discredited” work of (two-time Nobel prize winning) researcher, Dr. Linus Pauling, I have subsequently discovered a means to live free of both cancer and heart disease, with the potential of greatly extending health, vitality and longevity. However I am typically laughed at and ridiculed by those who I attempt to help with these discoveries, even when my explanations are demonstrably plausible.

            In regard to Dr. Pauling, what gave me pause was one fact that is often overlooked. Pauling lived to be 93 years of age — with everyone genetically related to him, dying 30 or more years sooner. Albeit anecdotal, this remains an unexplainable anomaly. It was this often overlooked aspect that made me curious — so I took a long look and am now forever grateful that I did. :-) But on this point at least, I am in great company, after watching Bill Gates being chastised by the normatives, simply by advocating for vaccination — as tho vaccine (an effective practice which has been in use since 1798) is a bad idea. Maybe it’s best if I just stand back and watch, selfishly guarding the knowledge I have gained, rather than end up constantly demonized like Bill Gates. :-/

  10. Some others have mentioned other metals. I’d draw your attention to the long term effects of manganese, present in many steel alloys. See manganism on Wikipedia, the long term effects are like Parkinson’s disease, tragic. Chromium has also been implicated with increased cancers noted around foundaries. Take care.

        1. This is not trivial, from memory Goldfranks Toxilogical Emergencies says that maganese combines with dopamine in the brain to ultimately break down to hydrogen peroxide that effectively destroys parts like basal amygdalas and even the pituatry gland. Common outcomes are very aggressive behavious.

          The is a large island north of Australia call Groote Eylandt which has a large surface deposit of manganese and it is now considered possible the extremely violent behaviours of the Aboriginal people in this location when first encountered related to manganese toxicity.

          It is not belived to be a recoverable toxocity.

          I am only aware of all this because I was working at construction of a port faciltiy where they were going to ship out manganese (and chromite, a whole other story, and then if the two combined, even worse) and they were not not really informing us of potential health issues so went and did my own research.

          1. Manganese is a necessary trace mineral that is present in tiny amounts in the body. It is found mostly in bones, liver, kidneys, pancreas. Manganese helps the body form connective tissue, bones, blood clotting factors and sex hormones. Excessive exposure however, can produce manganese toxicity, which can result in permanent neurological disorders with symptoms that include tremors, difficulty walking, and facial muscle spasms. These symptoms are often preceded by other lesser symptoms, including irritability, aggressiveness, and hallucinations. Manganese toxicity is most often a risk for people who mine the mineral or refine the ore. Dietary exposure to more than 11 mg per day is probably excessive for most adults.

  11. I feel like my generation of ‘makers’ is much more cognizant of dangers in the shop. Welding galvanized, gloves/hair around rotating things, media blasting (silica dust), various off-gassing (like with ABS), etc etc. Do any of these things on YouTube without the correct PPE and I feel like you’ll get 100 comments in an hour. Makes me wonder what we still do that the next generation of makers will say “what were they thinking?!”

    1. Welding by hand. I mean, I enjoy it, but I bet you in 100 years that’ll be looked at in much the way we look at hatters using mercury for wool stabilization. It’ll all be CNC in a fab somewhere with inert atmosphere and vented to air scrubbers.

  12. Compare the OSHA guidance for Zinc with those for Beryllium.

    I had a fight over getting galvanized steel spot-welded, where the zinc products would condense between the steel plates, due to people over-reacting as if zinc was chemical-warfare. In the industry they sell sticks of zinc to be used by welders to overcoat/restore galvanized steel in areas where welding blasted the original zinc.

    It sounds like the blacksmith created a hazard where there had previously been none because of terror tales told by those with insufficient experience.

    As I indicated at first, if OSHA isn’t putting a skull and crossbones on it, the danger level for typical industrial applications is low. Sure, no one likes flu symptoms and it may cut paid time on the job and is worth avoiding.

    I knew people with “Monday morning fever”, aka hangover from Sunday night drinking. I bet zinc fumes would not help and without them the workers would not get sympathy.

      1. We also shouldn’t expect industrial settings to keep the same schedule from Monday to Friday. If you’re trying to get a batch of orders done before the weekend, the work you’re doing near Monday is preparation work like cutting and grinding pieces which will release metal dust. By Thursday, that batch of parts is likely in QA or final treatment like painting.

        Another large factor would be lag time between exposure and contacting health officials. I’m an exception with good health insurance and plenty of disposable income, but even I’m hesitant on seeing doctors due to the expense. Blue collar workers in worse environments are going to be looking at a hospital bill a lo more aphrenisably. If you don’t think it’s life threatening and urgent, you’d probably avoid weekends and try for a GP appointment rather than ER visit to reduce copay and you’d probably wait 12 hours or more after symptoms start to see if it seems more series or will go away.

    1. Having an oxygen source around your face while welding is probably not a great idea due to the oxygen’s ability to make things much more flammable. Air is what you need not oxygen.

  13. Speaking of old wives tales. Years ago, a welder who helped me make a woodstove out of an old galvanized hot water tank said that drinking buttermilk after welding or cutting galvanized metal would prevent you from getting sick — he did it after we finished. Same guy also claimed he could talk a wart off your hand, so who knows.

    1. Okay, I have an answer. Maybe. You know how most people seem to have a mild milk allergy, when you drink milk, you trigger a histamine release which results in the production of mucous in your esophagus and bronchi. Most people develop mucous and even cough up bronchial mucous after drinking milk, I find. A layer of mucous would aid in trapping and expelling metal vapor smoke particles by becoming entangled with the mucous. This seems plausible to me at least — a way to explain the anecdotal claims that drinking milk prevents metal vapor toxicity.

  14. So basically a form of metal allergy then? Anything with nickel has always brought me up in a blistering rash if I wear it against my skin, and just recently I have become sensitive to copper(or possibly something else in the bronze pendant I was wearing?). Stands to reason that inhaling that crap might trigger an unpleasant immune response.

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