Will Fusion Energy Always Be Forty Years In the Future?

 

Indulge me in a little stroll down Nerd's Memory Lane.

 

When I was in high school, I heard about an upcoming talk on nuclear fusion that was going to be part of some publicity event in a new Fort Worth theater.  As my grandmother was the theater director's secretary, that may be how I found out about it.  Anyway, I went.

 

It was a good crowd, and the guy presenting the talk described what nuclear fusion was in layman's terms, talked about what had been tried so far, and went into considerable detail.  This was probably around 1970, mind you.  Hydrogen bombs (more exactly, thermonuclear weapons) which are still the only way we know how to produce a large amount of energy with fusion, were less than twenty years old.  The speaker may have mentioned tokamaks and plasmas and so on, and while I was listening I thought of a question to ask him at the end.

 

There were several people lined up before me, and the guy, who looked plenty old enough to me to be an Authority (although he was probably only about 40), patiently answered all the questions people had, even stupid ones.  I was the last person in line.  I asked him if somebody had thought of using feedback control to stabilize plasmas, and he said yes, that was one thing they were considering.  I felt thrilled to have thought of something that would almost certainly become an important source of energy by the time I was his age, or a little older.

 

Well, fast-forward fifty-one years or so.  No one has yet put a single watt-second of fusion energy into a power grid anywhere.  On the website of the electrical engineering profession's general-interest magazine IEEE Spectrum, there is an interview with a professor of science journalism named Charles Seife who thinks the latest "milestone" announcement by the U. S. National Ignition Facility (NIF) is not so much a milestone as they claim it is.  More like so many minutes on a treadmill, perhaps.

 

What the NIF announced was that they managed to ignite a lump of fusion fuel to the extent that it made 1.3 megajoules of energy.  Just to put that in perspective, that's about the energy content of a pound (0.45 kg) of gunpowder.  I don't know how many billions of dollars has been spent on the NIF, but if that's all they can do with it so far, it'd be a lot cheaper to wait till New Year's and buy a lot of firecrackers.

 

Not to be too cynical, Seife admits there is a legitimate reason to keep the NIF running, but he thinks it has little or nothing to do with the practical goal of fusion energy.  The NIF was founded to study nuclear weapons, because the same basic process is used both in thermonuclear weapons and other types of fusion processes.  As long as we in the U. S. wish to remain members of the nuclear-weapon club, we need to keep our thermonuclear powder dry, so to speak, which means maintaining experts that know how to make sure the bombs will go off when we want them to, and not otherwise.  So letting them fool around with stuff like the NIF keeps them occupied and in practice for checking nuclear weapons without actually setting them off above ground, which is forbidden by the Nuclear Test Ban Treaty.  Technically, we can test them underground, but because seismological instruments can tell almost anybody nearly as much about the test as we could find out ourselves, that's not done a whole lot either—the last U. S. underground nuclear test was in 1992. 

 

However, selling the public on keeping nuclear-weapons scientists in fighting trim is a hard job, while promising them electricity "too cheap to meter"—a famous catch-phrase of early proponents of fusion power—is a lot easier.  The elephant in the fusion lounge is ITER, the International Thermonuclear Experimental Reactor, a multinational collaboration based in France which has been keeping lots of mainly European scientists and engineers busy since 1979, or only a few years after my conversation with the fusion evangelist.  ITER's latest deadline to first make plasma is 2025, although they have had considerable schedule slippage over the years.  And who knows how far it will be between making plasma (which any neon sign does whenever you turn it on) and making money by selling electricity made from fusion energy?

 

From an ethical point of view, the main issue I see here is how scientists present their work to the public.  Some things are inherently easier to sell in some cultures than others.  For some reason which may have to do with the displacement of faith in God by faith in the Universe or science, U. S. astronomers are able to extract some $30 billion a year from the federal government, roughly speaking (this includes all of NASA's budget and the NSF budget for astronomy-related activities).  In a day when Congress tosses trillions around like popcorn, that doesn't sound like much.  But for an activity which explicitly excludes profit motives—who ever made money off the Andromeda Galaxy?—that's a good chunk of change.  By and large, the public agrees with astronomers that what they do is cool, and pays for it.

 

Maybe the NIF people need to jazz up the coolness of what they're doing.  I've seen photos of a similar facility, the Z-machine at Sandia Labs, which outdoes anything in Frankenstein's lab for impressiveness.  Of course, just saying you do cool things with sparks or lasers will only take you so far.  But it might be worth a try, rather than setting up goalposts that promise more than they deliver.

 

Sources:  The interview with Charles Seife is at https://spectrum.ieee.org/has-fusion-really-had-its-wright-brothers-moment.  The energy comparison with gunpowder is from https://chesterenergyandpolicy.com/2017/12/27/the-hidden-energy-of-new-years-even-celebrations-measured-in-joules/#:~:text=While%20most%20real%20firecrackers%20are,48%20J%20of%20explosive%20energy and the date of the last U. S. underground nuclear test is from https://allthingsnuclear.org/emacdonald/is-the-united-states-planning-to-resume-nuclear-testing/.  A photo of the z-machine in operation is at https://www.sandia.gov/z-machine/.

Federal Safety Agency Investigates Tesla Autopilot

 

In 2015, the upstart automaker Tesla introduced its Autopilot feature, an advanced artificial-intelligence-enabled system that takes over most of the routine operations that a human driver normally performs.  At the same time, Tesla warned Autopilot users that they should remain attentive with their hands on the wheel at all times, even when Autopilot is engaged.

 

This is a little bit like taking a hungry child into a candy store and telling them not to touch anything.  Most kids will obey, but it's hard on the kid and it can lead to embarrassing situations.

 

It's not surprising that, according to the U. S. National Highway Traffic Safety Administration (NHTSA), since 2016 ten people have died in eight crashes of Tesla vehicles in which the Autopilot feature was the cause of the crash.  Lately, there have been numerous crashes, one of them fatal, in which Teslas with Autopilot engaged have run into the rear of emergency vehicles with flashing lights. 

 

Finally, the NHTSA has had enough.  It has launched a formal investigation into how the Autopilot system works, how it is implemented, what its defects are, and what steps Tesla has taken to make sure that drivers are paying attention like they are supposed to when the Autopilot is driving the car.  There is abundant evidence that in many of the crashes, the driver was doing something other than watching the road:  watching a movie, playing a video game, or even sitting in a seat other than the driver's seat.  The Autopilot system is supposed to monitor hand pressure on the steering wheel, but according to some sources, this feature is very easy to defeat, and many people appear to have done so.  And most of them probably get away with it most of the time.  But not always.

 

In human-machine safety issues, there is a tradeoff between the two poles which represent extreme approaches to operating a device safely.  One pole relies totally on training the individual not to do dangerous things, or to do them in a safe way, if that makes sense.  Think of stunt drivers in the movie business:  they do things with cars that cars are not designed to do, but with careful planning and finely-honed skills, they manage to survive car flips, crashes, and other tricks that have probably passed into history now that CGI technology is so good that real stunt drivers are probably looking for work.  But the point is that this approach to safety concentrates on the knowledge and attention of the operator or driver, and basically tells him or her to drive safely.

 

The other pole of safety is building in foolproof safety features to the machine itself, so that even an ignorant five-year-old turned loose with the keys couldn't get hurt.  It's not possible to make a car at a reasonable price that is completely safe no matter what you do—at least not yet.  But many of the autonomous-vehicle-type features that are now showing up on many makes besides Tesla move in this direction:  lane-keeping features, automatic braking to avoid head-on collisions, and so on.  They make up for a driver's deficiencies, inattention, or errors.  But they are far from perfect yet, and so the attention and intelligence of the driver are still needed to fill in the gaps where systems like Tesla's Autopilot still can't figure out the situation, such as an emergency vehicle stopped in your lane.

 

I expect the NHTSA will encounter some headwinds in trying to figure out Tesla's Autopilot system.  Elon Musk has, shall we say, a rather cavalier attitude toward convention and traditional ways of doing things, and recently abolished Tesla's public-relations department.  Perhaps he thinks a few tweets from him do just as well, and in the absence of more formal ways of getting information from the company, he may be right.  But nobody can stop the NHTSA from renting or buying some Teslas and putting them through various scenarios and seeing what they do with and without human supervision.  Whatever is going on under the hood, the results will be clear to see.

 

But just testing the hardware and software is only part of the issue.  The poisonous mixture that the NHTSA is dealing with combines an Autopilot system that is very good—so good that people really can let it drive the car for many minutes at a time and get away with it—and drivers who either intentionally put too much trust in the Autopilot system, or simply get distracted and fail to do what they know they ought to be doing, which is looking at the road.  But nobody just accidentally starts watching a movie or playing a video game, and so we must conclude that in at least some of the cases where inattention and the Autopilot have caused crashes, people simply ignored the advice of Tesla to not let Autopilot drive the car by itself, and paid the penalty for their inattention.

 

Now in some countries and cultures (and political persuasions—notably extreme libertarianism), this would not be a concern of the government's.  If people want to do foolish things and ignore instructions, well, let them do it and suffer the consequences.  The problem with this attitude is that it ignores everybody else, particularly other people who might be harmed and killed in the same accident.

 

My point is simply that we in the U. S. have grown accustomed to holding automakers to safety standards that avoid preventable accidents, in the sense that preventable accidents follow a consistent pattern which reasonable interventions at not too much cost can prevent. 

 

We are in a curious transition phase in which systems like Autopilot are good enough to fool us that they can really drive our cars without us paying any attention, but not good enough to do it for real.  And until it is just as safe to play pinochle from the driver's seat as it is at home, we need some way to remind drivers that they can't ignore the road even if the car seems to be driving itself.

 

Sources:  I consulted an article in Consumer Reports at https://www.consumerreports.org/autonomous-driving/nhtsa-safety-defect-investigation-tesla-autopilot-crashes-a6996819019/ and an article in the Aug. 16 Austin American-Statesman online edition "Feds Open Investigation Into Tesla's Autopilot System.  The statistic on total fatalities and accidents due to Autopilot since 2016 was obtained from https://thehill.com/changing-america/sustainability/infrastructure/561717-increasing-number-of-crashes-involving-teslas#:~:text=In%20total%2C%20at%20least%2010,each%20year%20in%20the%20U.S.

Forensic Engineer Discovers Design Flaw in Surfside Condo That Collapsed

 

On June 24, a thirteen-story condominium building in Surfside, Florida, known as Champlain Towers South collapsed, killing 98 people.  The building was shortly due for a 40-year reinspection, but previous inspections had noted serious cracking and corrosion problems.  The U. S. National Institute of Standards and Technology (NIST) is conducting an extensive investigation into the collapse, and their findings will probably be regarded as definitive.  In the meantime, however, a private Florida firm called Consult Engineering undertook to do an investigation on their own, based primarily on publicly available prints of the building's construction.  And they have discovered a serious design flaw which, combined with aging, may well account for the way the building collapsed.

 

Consult Engineering is headed by Joshua L. Porter, who specializes in forensic engineering of existing structures.  He used the same design equations and approaches that the original designers used in 1979, when the building was under construction, and studied the prints he obtained to determine which ones were for planning only and which ones expressed the way the structure was actually completed ("as built.")  He also consulted recent videos taken inside the structure and the videos of the actual collapse, and produced a 40-minute YouTube video of his own that presents his conclusions.

 

While I am an engineer, my specialty is electrical, not mechanical, and I had to pause Mr. Porter's video several times to figure out what he was talking about.  But the video was worth watching, because he has found a significant difference between the original design and a revised design that was issued in January of 1980, during the construction of the building.  What follows is my summary of what Mr. Porter found.

 

Partly to maximize the space available under a then-existing 12-story zoning limit in place when the condominium was built, an excavation was made below grade for a parking garage beneath the structure.  This meant that the ground or lobby floor, which was also partly designed for parking, had to support the live loads of automobiles driving over the poured-concrete slab floor. 

 

To support the floor, concrete columns were poured, and in many places these were substantial ones, 24 inches square (61 cm x 61 cm).  Others were smaller, 16 inches square or even 12 inches by 16 inches.  Mr. Porter used the hand-calculation methods that were state-of-the-art for 1979 and discovered that the load of the slab on the columns was in many cases right up to the edge of what he calls the "punching shear" limit. 

 

Punching shear can be explained this way.  Imagine taking a square piece of cardboard from a corrugated cardboard box, and a sharpened pencil.  With one hand, put the pencil point-downward on the floor and place the cardboard on the eraser end, and mash down on the cardboard.  You will probably break the tip of the pencil first.  That means you have not exceeded the punching shear limit of the cardboard yet.

 

But then, try the same thing with the eraser end of the pencil on the floor and the pointed end on the cardboard.  It won't take much pressure to make the pencil point punch through the cardboard.  This shows that the bigger the column at the attachment point to the slab, the stronger the system is with regard to the danger of punching shear, which is the column punching through the slab.

 

In the original 1979 drawings, there was a one-foot step or drop at the ground-level (lobby) floor between two areas.  There were planned planter boxes over part of this area—rectangular concrete tubs in which dirt and shrubs were planted and watered.  And there were cars parked over another part of it.  Partly to support the cars and planter boxes, and partly to allow for the one-foot step, the engineer had placed several concrete beams between the columns underneath these extra loads.  A beam is just a thicker piece of concrete reinforced and cast into the floor, which strengthens the floor in that area and transfers loads to the columns it connects to.  These beams were about a foot thick and would have safely carried the extra vehicle and planter-box loads.  One beam was built into the one-foot drop, which was one reason for the beam to be there.

 

But in a January 1980 revision of the drawings, the architect decided to eliminate the one-foot drop.  Surprisingly, the engineer also eliminated all the supporting beams that went along with it.  So in one case there were automotive live loads within a foot or two of small 12-by-16-inch columns.  And in a photo of the building's exterior taken before the collapse, Mr. Porter found that several planter boxes had been built in places that no existing print allowed for, further increasing the punching shear load on the smaller columns.

 

Mr. Porter's conclusions were that several aspects of the building design were executed with no margin of safety—loaded exactly to 100% of their carrying capacity.  This allowed no margin for corrosion damage, which was abundantly evident in recent photographs.  But the most serious flaw was the lack of beams underneath cars and planter boxes, right in the area where the initial failure apparently occurred.  From eyewitness reports and videos, the first failure was apparently when the lobby (ground floor) slab had a punching-shear failure and collapsed into the basement, leaving several smaller columns without support over a 20-foot length rather than their designed-for 10-foot length. 

 

The building stood for several minutes after that, and a few people managed to escape.  But with the lobby floor gone, the middle of each column formerly attached to the lobby floor was now unsupported sideways.  That, together with forty years of corrosion and cracking, probably induced one of the columns supporting the main building to buckle.  Once it went, the lack of safety margins meant that adjacent columns were overloaded and buckled, and the building was doomed. 

 

There is nothing official about Consult Engineering's analysis of the Surfside condo collapse.  But coming from a professional whose business it is to do such studies, it seems highly persuasive.  Last-minute changes in construction can be deadly, and this tragedy may be yet another example of this principle.

 

Sources:  The Consult Engineering presentation on the Surfside condo collapse can be viewed at https://www.youtube.com/watch?v=WaZcyq7YsNA.  I also referred to Wikipedia's article "Surfside condominium collapse." 

 

Two Logics and Engineering Ethics

 

Though most of us never give a second thought to philosophers, we live in cultures which have underlying philosophical assumptions that are rarely examined.  Just as some things are hard to say in certain languages, some thoughts are hard to think in certain philosophies, including certain kinds of thoughts about ethics and morality.

 

Logic can be considered as a sort of language of philosophical thought.  It turns out that over the past century or two, there has been a revolution in the type of logic that has been taught and accepted by most philosophers, and as a result this revolution has insinuated itself through most Western cultures.  But there are a few philosophers who think this almost unnoticed shift has had profound effects that almost nobody understands.  And I'd like to take the rest of this space to explain why.

 

You might think that logic is just logic, but if you look a little deeper you will find that philosophers have come up with basically two different kinds of logic.  Historically, the first philosopher to take a disciplined academic look at logic was Aristotle, who lived from about 384 B. C. to 322 B. C.  His book on logic sets out various ways to argue from premises (things you believe or know are true) to conclusions, which are things that must be true if the premises are true.  One of these ways is the syllogism:  "All men are mortal; Socrates is a man;  therefore, Socrates is mortal."  The first two phrases are the major and minor premise, respectively, and the third phrase is the conclusion, which must be true if the premises are true.

 

Philosopher Henry Veatch calls this classic Aristotelian kind of logic "what-logic," because it is based on an intuitive, common-sense notion of what things are.  Aristotle believed that people could look at things and determine what they were essentially, at least to some degree.  Most people can tell apples from oranges, for example, and Aristotle would say that's because the essential makeup of an apple is different from the essential makeup of an orange. 

 

Aristotelian logic reigned until philosophers of the Enlightenment, such as David Hume (1711-1776) and Immanuel Kant (1724-1804) began to question things that up to then were thought to be obviously true.  The details are complicated, but basically, they began to say things like, "When you see an apple, the only thing you can be sure of isn't the apple itself—it's the idea of an apple in your mind."  Grossly oversimplified, Hume and Kant and their followers began to treat human thought and language as the only things we could be sure of, and tried to work outwards from thoughts to things in the outside world.  They believed that we could never really know what a thing is, and there was no point in trying.

 

In the centuries since then, among most philosophers Aristotelian what-logic has been replaced by what Veatch calls "relating-logic."  Another name for it is symbolic logic.  Electrical engineers have encountered it in the form of Boolean algebra, and it is embodied in all digital computers in the form of logic gates that perform logical functions like AND and OR. 

 

While symbolic logic has proved to be extraordinarily useful—computers excel at it, naturally, and philosopher Peter Kreeft compares the change from what-logic to relating-logic to the shift from Roman to Arabic numerals—it has some basic shortcomings.  The most serious is this:  it can never tell you what a thing is; it can only say how things relate to each other.  Here is Veatch on this defect:  "To take the case merely of human actions . . . since there is no such thing as a human nature that can be appealed to in a relating-logic, there is no way in which one can determine what man's function is or what sort of activity a characteristically human life must consist in."  For the purposes of ethical reasoning, these are major problems.  If you can't answer the question, "What is human nature?" you can't very well say this aspect of human nature or this action is better than that one. 

 

Kreeft, who has taught philosophy at Boston College for four decades, says that symbolic or relating-logic has taken over so thoroughly that it is beginning to disable his students from understanding aspects of reasoning that depend on what-logic:  analogies, for example.  After Kreeft had published a criticism of certain aspects of computers, a well-known expert phoned him and predicted that as society began to think more exclusively in the relating-logic computer mode, ordinary intuitive understanding would atrophy and the SAT (Scholastic Achievement Tests, formerly used for college admissions) would drop its section on analogies as fewer people could figure them out.  This actually happened a few years later.  Kreeft dusted off some old logic exams from 1962 and gave them to his current 21st-century students, and they failed spectacularly, especially when it came to analogies.  For example, in the sentence, "He pointed with his right hand to the hands of a clock," the word "hands" is used analogically.  But only three out of 75 students understood that.

 

Kreeft claims that losing the ability to do what-logic is tragic, and may be either a result or a cause (or both) of everything from the rise of utilitarian ethics ("the greatest good for the greatest number") which is a favorite of engineers, to the sexual revolution, which does not recognize anything like the natural form or "nature" of human sexuality. 

 

While relating-logic is great for making things work, it fails to tell us what anything really is.  And to the extent that modern thought and discourse increasingly exclude types of reasoning based on what-logic, we seem to be dumbing ourselves down to act more like computers and less like human beings.  In The Magician's Nephew, C. S. Lewis said, "Now the trouble about trying to make yourself stupider than you really are is that you very often succeed."  In leaving Aristotelian logic behind, the Western world may be doing exactly that.

 

Sources:  Peter Kreeft's article  "The Social, Moral, and Sexual Effects of Symbolic Logic" in his How to Destroy Western Civilization and Other Ideas From the Cultural Abyss (San Francisco:  Ignatius Press, 2021) contains a reference to Henry B. Veatch's Two Logics (Evanston, IL:  Northwestern University Press, 1969) and explains this situation a lot better than I did.

Nearly $1 Million In Fines Proposed for Deadly Liquid-Nitrogen Accident

 

Last January 28, workers at the Gainesville, Georgia chicken-packing plant operated by Foundation Foods began to show up for work.  Several workers were assigned positions in the below-ground-level freezing room on Production Line 4, one of several in the large plant.  Not too long before, the old ammonia-refrigerant freezing system had been replaced with a new liquid-nitrogen (LN2) system.

 

On the face of it, liquid nitrogen is a safer chemical than ammonia, which is both toxic and explosive.  Nitrogen makes up 78% of the atmosphere, and while liquid nitrogen can cause painful burns, as long as it is confined to locations inaccessible to workers, no direct harm from it can result.  However, breathing nitrogen gas cannot support life.

 

The freezing stage itself was in a separate freezing room, and consisted of an immersion freezing line in which the chicken pieces were immersed in liquid nitrogen at around -321 F, followed by a spiral freezing chamber where the gaseous nitrogen boiling away from the liquid surrounded the pieces as they spiraled upward on a conveyor belt. 

 

Just after the shift started, Line 4 had a problem, and three maintenance workers entered the freezing room.  What they apparently didn't know was that the malfunction had filled the entire room with evaporated liquid nitrogen, displacing most of the oxygen in the room.  The workers immediately passed out and died shortly thereafter.  Two more workers entered the room and died, and a sixth was sufficiently overcome that he died on the way to the hospital.  The release of liquid nitrogen created a condensation fog that made escape difficult, and at least twelve other workers were injured enough to require hospital care. 

 

Both the U. S. Chemical Safety Board (CSB) and the Occupational Health and Safety Administration (OSHA) began investigations of the accident.  In February, the CCB issued some preliminary updates, and on July 23, OSHA announced its intention to assess Foundation Food Group Inc. (the plant operator), Messer LLC (the LN2  supplier), Packers Sanitation Services Inc. (the cleaning and sanitation service provider) and FS Group Inc. (the equipment and mechanical servicing provider) a total of nearly $1 million in fines.

 

OSHA found 26 violations committed by Foundation Food Group.  The agency discovered that the workers at the plant had received no training or warnings about the hazards of LN2 and safety precautions they should observe.  There were no written lockout procedures dealing with how maintenance should be performed.  While the following is reading between the lines, something like this accident could have occurred if someone had shut off the LN2 supply to the system while leaving an LN2 valve or joint open in the freezing room, and then someone else came along and opened the shut valve, not knowing it would kill six co-workers. 

 

Lockout procedures are vital for work on hazardous equipment of all kinds, ranging from conveyor belts to high-voltage power systems.  If equipment is being worked on, a typical lockout procedure specifies brightly-colored tags that must be placed on critical controls in a way that will prevent the control from being operated.  Evidently, nothing like this was done.

 

Another standard safety measure is to train everyone who has a reason to work inside a confined space where hazardous gases (such as pure nitrogen) can accumulate.  Ideally, an oxygen monitor or some way to indicate a problem with the air inside the room should have been operating, but at least the workers should have been made aware of the possible danger.  That way they might not have simply walked into the room to their certain deaths. 

 

If a person strays into an area where there is no oxygen but the air pressure and other conditions seem normal, there is usually no time to react, turn around, or do anything except pass out and drop.  I once saw a dashcam video taken from a state trooper's car.  The trooper had stopped to investigate an accident involving a liquid-ammonia truck.  The gas had been released invisibly, and you can watch as the trooper walks toward the truck and then falls as if shot through the heart, and eventually dies.  Even the miserable coal miners of nineteenth-century England were able to bring a canary into the mine with them to give advance warning of "black-damp"—air without enough oxygen to breathe.  But canaries wouldn't be allowed by the microbiologists who rule meat-packing plants—too unsanitary.

 

While there was probably some mechanical malfunction that caused the initial release of nitrogen, the fatalities could have been avoided with better communication among all the parties involved.  The factory operators needed to give instructions in their employees' native language (Spanish) about the hazards of working around LN2.  The LN2 supplier needed to communicate with the factory operators and maintenance workers concerning the delivery and transmission of their product.  And the maintenance and supervisory personnel in charge of fixing Line 4 needed much better lockout and safety procedures, which were signally lacking in this tragic case.

 

Vigilance is perhaps not taught that much in business schools.  It sounds like an old-fashioned, rather static virtue, somewhat passé when compared with flashier virtues like competitiveness and enterprise.  But clearly, whatever safety procedures and safety officers were in place in the Gainesville plant on last Jan. 28 were sadly inadequate to prevent a tragedy that didn't have to happen.  Not everybody enjoys going around their place of business imagining what could go wrong and how to keep it from happening.  But that's the main job description for those charged with the safety of workers, and it's a job that looks like a loss on a company's balance sheet until something like the LN2 accident happens.  Then it's a lost opportunity, and the beginning of something much worse. 

 

Sources:  OSHA's press release on the fines assessed so far regarding this accident can be found at https://www.osha.gov/news/newsreleases/national/07232021.  Some preliminary findings of the CSB are at https://www.csb.gov/third-csb-update-on-poultry-plant-incident/.  I also referred to a news article at https://www.npr.org/2021/07/23/1019784347/six-poultry-workers-died-from-a-nitrogen-leak-osha-has-issued-1-million-in-fines.  I previously blogged on this topic on Feb. 1, 2021 at https://engineeringethicsblog.blogspot.com/2021/02/six-die-from-liquid-nitrogen-accident.html.