To: Dr. Damian Bailey, Dr. David Poole, Dr. Vaughan Macefield
68 Editors and Reporters, The Conversation, USA & Australia
Re: Rebuttal, clarification and additional information:
Silent but not serene: what science says about nitrogen death, The Conversation, 18 November, 2025, by Damian Bailey, Professor of Physiology and Biochemistry at the University of South Wales, David Poole, Professor of Kinesiology at Kansas State University, and Vaughan Macefield, Professor of Neuroscience at Monash University
From: Dudley Sharp, independent researcher, death penalty expert, former opponent, 832-439-2113, CV at bottom
Method I quote BPM, the three authors (1), or P&B, the two authors (2) and reply as Sharp
Intro
As the authors felt it unimportant:
Elizabeth Sennett was murdered by Kenneth Smith and John Parker, who were hired by her husband, Rev. Charles Sennett Sr. They ambushed her in her home. The murderers "blind-sided her." with a beating in which the victim apparently struggled for her life. The evidence indicated that during the beating any item within reach was used as a weapon. The men apparently used every piece of a fireplace set, a walking cane, and a piece of galvanized pipe and, after beating her, stabbed her eight times with a survival knife, in the chest, neck, face, and scalp.
How long this horror lasted and how long Elizabeth was conscious I could not find. Possibly, BPM will research.
Preface
There are huge amounts of evidence of peaceful deaths, with nitrogen gas, particularly within industrial accidents, wherein sudden unconsciousness, with no warning, with death to follow,
after being overcome by nitrogen gas: 80 deaths and 50 injuries (3), just within 10 years, 1992-
2002, with more since then and just within one country, the US.
BPM left them out.
Three of many: The Valero incident prompted Chemical Safety and Hazard Investigation Board (CSB) member John Bresland to remind stakeholders:
"Nitrogen is a silent killer.
You will not recognize you're in trouble in time to take action to save yourself," (3)
The most famous was from NASA, March 1981. John Bjornstad and Forrest Cole died
from asphyxiation. Bill Wolford was critically injured trying to rescue others. Jimmy Harper & Nick Mullon both fell victim but survived. (4)" . . . not recogniz(ing) you're in trouble in time to take action to save yourself," (3)
"An oxygen concentration below 6% would lead to fainting within a few seconds, with possible severe brain damage or even death if unattended. Severe convulsions have been observed with pure nitrogen asphyxia after 2-3 minutes" (5).
These are, clearly, important, within this debate and BPM left them out. That should give you some obvious caution with BPM, as is also warranted, here:
1) P&B have this: "Consequently, depending on the ventilatory response, the individual's (murderer's) specific functional residual capacity and whether the room air‐to‐nitrogen switch is made at the end of a quiet exhalation (i.e., at functional residual capacity) and the precise metabolic rate (O2 uptake), the accessible O2 stores could be expended within 2–6 min or less. However, as seen in the next subsection, while breathing 100% nitrogen the brain will become O2 deprived far more rapidly (than that 2-6 min)". (2), meaning less than 2 minutes is confirmed, in some cases.
" . . . . (murderer) Smith would have been expected to show signs of severe discomfort and distress with intolerable air hunger for ∼1 min and dying within 5–6 min had he been switched to 100% nitrogen in his mask." (2)
"In humans, Ernsting found that breathing pure nitrogen induced collapse, convulsions and unconsciousness within 17–20 seconds (Ernsting, 1963) " (2)
Sharp: Because this is an execution, the murderer's pulse rate, blood pressure and respiration rate will all be elevated, making unconsciousness and death faster, meaning unconsciousness faster than 17-20 seconds and " . . . the brain will become O2 deprived far more rapidly (than that 2-6 min)". (2), with 100% nitrogen, based within P&B's analysis, but without either fn 1 or 2, discussing the murderer's elevated pulse rate, blood pressure and respiration rate, because of facing execution.
Smith, as others, will be unconscious prior to any "severe discomfort and distress with intolerable air hunger", which is not intolerable.
For those who don't know what air hunger is,
I swim underwater, primarily, and routinely and intentionally experience air hunger, very minor discomfort no panic. It is an automatic reflex action as your body responds to low oxygen levels and, when underwater, sounds and feels like a combination of burping and swallowing, at the same time. It's very odd. No pain, no panic, whatsoever.
Anyone can duplicate that, by holding your breath, until those involuntary spasms, easier underwater.
For those murderers wanting to put on a show, during nitrogen executions, as we have seen, they have, likely, prepared holding their breaths for an extended period of time, meaning they have experienced air hunger, prior.
With the murderer facing execution, pulse rate, blood pressure and respiration rates will be elevated, meaning that symptoms from nitrogen will occur faster than 12-14 seconds (2) and unconsciousness will occur faster than the 17-20 seconds (2), as detailed.
Any panic and/or distress from the murderer is going to be based within their pending execution, not air hunger.
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2) P&B: "Given the politically charged nature of exacting the death penalty and that it is clearly an infraction of the Hippocratic oath . . . " (2)
Sharp: "Clearly". This is how bad P&B are.
Here we have the anti-death penalty norm: No fact checking nor vetting or pretending that is the case (6).
The Hippocratic Oath bans both physician assisted suicides and abortions, not executions (7), with this expected ethical result:
With abortions and assisted suicides, physicians kill millions of innocents, per year, while
protesting the executions of guilty murderers, which averages 33 /yr. in the US.
It is classic anti-death penalty: sparing murderers lives while sacrificing more
innocents (8.9).
What else did P&B not fact check nor vet and/or keep from the readers?
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4) NOTE: The death penalty/executions save and protect innocent lives, in six ways, better than does life without parole (LWOP) (8).
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5) BPM: "In the past year, several US states have adopted nitrogen gas as a method for inmate execution, and a nitrogen‑filled “Sarco pod” (short for sarcophagus) euthanasia device has made headlines in Switzerland. While both claim to offer a calm, painless death, the science tells a different story." (1)
Sharp: No, it does not. The minimum time to unconsciousness will be less than the 17-20 seconds (let's say 16 seconds or less) of breathing 100% nitrogen gas, as the murderer is facing execution and will, thereby, have higher pulse, blood pressure and respiration rates
6) BPM: "Nitrogen asphyxiation kills by replacing breathable air with pure nitrogen, starving the
brain and body of oxygen. It is described by some commentators as humane – a supposedly
peaceful fading into unconsciousness without pain or panic. But the physiological reality is far more disturbing. "
Sharp: The physiological realities do not overcome the unconsciousness and the absence of
panic and pain, while unconscious. As detailed, below, there might be 0-2 seconds of distress,
related to the nitrogen, specifically, which will be nothing compared to the murderer's anxiety of being executed for the murder of innocents.
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7) "Kety (1950) has calculated that at any one moment the total oxygen content of the brain and of the cerebral capillary blood is about 7 ml. Thus at the normal level of cerebral oxygen consumption the oxygen tension of the brain following cessation of the supply of this sub stance would be reduced to zero in about 8 sec..These results suggest that when unconsciousness supervenes following the sudden induction of severe cerebral hypoxia (nitrogen execution) the cellular oxygen tension in many regions of the brain will be virtually zero." (Ernsting, 1963) " (2)
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8) BPM: "As oxygen levels plummet, the body’s survival systems erupt into panic. People gasp, choke, thrash and experience terrifying air hunger as their cells suffocate. These are not the signs of a gentle passing but of a body desperately fighting for life."
Sharp: Tell us, exactly, when the survival symptoms erupt, maybe 11-13 seconds, with less than 17 seconds it takes to become unconscious. 0-5 seconds? Less? Do you know? No.
According to the U.S. Chemical Safety and Hazard Investigation Board, in humans, "breathing an oxygen deficient atmosphere can have serious and immediate effects, including unconsciousness after only one or two breaths. The exposed person has no warning and cannot sense that the oxygen level is too low." (3), which rejects the conscious air hunger from BPM.
All of those symptoms are commonly known as death throes and/or air hunger, aka oxygen deprivation, which do not overcome the peaceful, painless death within unconsciousness.
9) BPM: "The shift (to nitrogen) has been driven by shortages of lethal-injection drugs . . .
Sharp: There is not nor has there been a shortage of lethal injection drugs. Police evidence rooms have huge amounts of fentanyl, free and available to the states, with not all needed for evidence, only, tiny amounts needed for executions and only testing for efficacy, prior to executions, with quick and painless deaths, as very well known. Both Nebraska and Nevada have fentanyl within their execution protocols.
It is a bizarre mystery why states are not using it.
Again, 1 or 2, no fact checking, no vetting nor critical thinking, regarding another issue.
10) BPM: "Yet eyewitness accounts from a recent execution reveal visible suffering lasting minutes before death: violent convulsions, heaving, gasping and desperate attempts to breathe. Advocates claim that removing oxygen while keeping carbon dioxide levels low prevents panic – a claim rooted in misunderstanding. The body is exquisitely sensitive to oxygen deprivation. Tiny sensors in our neck, called carotid bodies, constantly monitor oxygen levels. When levels fall, they trigger powerful signals to breathe harder. This response, known as air hunger, is one of the most distressing sensations humans can experience. Unlike drifting into unconsciousness under anaesthesia, oxygen starvation brings an overwhelming feeling of suffocation, panic and terror."
Sharp: 1) What BPM calls "visible suffering" is visible evidence of movements, outbursts, etc. which are not evidence of suffering but of death throes, oxygen deprivations, etc, which does not overcome unconsciousness, in less than 17 seconds, meaning no panic nor pain.
Some death throes will be quite violent, others quite small, with all being unconscious reflex.
2) With nitrogen gas executions, it was predicted that murderers would hold their breaths, for as long as possible, 3-4 minutes, if properly prepared, while thrashing with their restraints, until 2-3 deep breaths were necessary, within that less than 17 seconds to unconsciousness, then death. All that activity will increase pulse rate, blood pressure and respiration, leading to faster unconsciousness and death.
That 3-4 minutes is not death throes, but, simply, consciously, intentionally, fighting the restraints, for drama. The death throes will show soon after unconsciousness.
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11) "In the few experiments in which nitrogen was breathed for 17-20 sec unconsciousness supervened and was accompanied on most occasions by a generalized convulsion." "The duration of the interval between the start of over-ventilation with nitrogen and the onset of symptoms was 12-14 sec" (Ernsting, 1963) " (2)
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12) BPM: "Even trained pilots, exposed to sudden oxygen loss at high altitude, describe severe breathlessness and confusion within seconds – that interval before incapacitating confusion constitutes a state known in aviation medicine as the “time of useful consciousness”. At 50,000 feet, pilots have less than 12 seconds before confusion sets in – and those moments are anything but peaceful, equivalent to breathing almost pure nitrogen at ground level. The experience is so traumatic that military and commercial pilots undergo hypoxia recognition training precisely to avoid confusion and loss of control when oxygen fails."
Sharp: Pain was never mentioned. No surprise.
13) BPM: "In nitrogen executions, the situation is far worse. Prisoners are restrained, unable to expand their chest fully against straps that restrict breathing, amplifying the sense of suffocation. Witnesses have reported prolonged movements and vocalisations, consistent with the body’s involuntary struggle to breathe – unmistakable signs of physiological distress, not serene unconsciousness."
Sharp: BPM have presented no contradiction to a serene unconsciousness. BPM have, only, presented what is, commonly, known as death throes and/or oxygen deprivation, while the murderer remains unconscious.
It is as if BPM are unaware that physiological distress and serene unconsciousness can exist at the same time. Strange.
14) Ernstine: "The concentration of oxygen in the gas contained within the respiratory tract at the beginning of the nitrogen breathing period was reduced very rapidly by the very large voluntary increase of pulmonary ventilation. The reduction of the lung volume to a minimum before the first breath of nitrogen was taken decreased the quantity of oxygen to be washed out. The combination of these two manoeuvres resulted in a very rapid fall of end-tidal oxygen tension to 10 mm Hg after 8 sec of over-ventilation."
(Ernsting, 1963) " (2)
Sharp: This is, of course, different that with nitrogen execution, which would, very likely, have a much quicker "very rapid fall of end-tidal oxygen tension to 10 mm Hg after 8 sec of over-ventilation.", with the second inhaling of nitrogen.
15) BPM: "A similar claim of a “gentle” death has entered debates over assisted suicide . . . with the Sarco pod – a 3D‑printed capsule filled with nitrogen . . . Its inventor, Dr Philip Nitschke, has said users “drift off peacefully”. However, there is no substantial evidence to support this."
"The first reported use in 2024 triggered a criminal investigation, and the lack of reported eyewitness accounts makes it impossible to know what the person experienced."
Sharp: How it is that you left out all of the eye witnesses in those industrial accidents, that showed the victims passing out with no warning. See Preface.
16) BPM: "The notion that breathing pure nitrogen induces calm probably stems from confusion with nitrogen narcosis – the intoxicating effect deep‑sea divers feel under high pressure. Yet this “martini effect” occurs only when nitrogen is breathed at several times normal atmospheric pressure."
Sharp: Which does not negate anything I have written.
17) BPM: "At sea level, nitrogen simply displaces oxygen, causing hypoxia and anoxia without any sedative properties. The result is not a blissful drift into unconsciousness, but a terrifying physiological fight for air."
Sharp: Unconscious within 17 seconds is quite the sedative, although not one. The physiological fight for air is reflex within an unconscious murderer.
18) BPM: "Breathing pure nitrogen can cause loss of consciousness within about 20 seconds as blood oxygen falls below critical levels. But even in that brief window, there are several agonising seconds of confusion and suffocation. Death soon follows as the brain and heart are starved of oxygen. Far from being humane, this process resembles drowning without water – silent, invisible, yet equally violent."
Sharp: Within those 17 seconds, or less, how long is there a conscious suffocation effect. BPM? Maybe 0-5 seconds prior to unconsciousness. Maybe? BPM goes as far as " . . . several agonizing seconds"? Can BPM prove any conscious agonizing effect within nitrogen executions? No.
19) BPM: "The ethical implications are profound."
Sharp: Most likely, there is no consciousness of physiological panic for the murderer. Profound. The panic is that the murderer knows they are being executed for murdering an innocent, not once mentioned by BPM.
20) BPM: "In response to concerns, three major suppliers of medical‑grade nitrogen in the US have banned sales for executions." (1)
Sharp: The concerns are, only, that they do not wish their products to be used in the executions of guilty murderers. That's fair.
How many pharmaceutical companies refuse to provide the drugs used for killing innocents in abortions or assisted suicides? Any? Why? Money? See Hippocratic Oath (6).
21) BPM: "Yet some policymakers present the method as clean and clinical, even though medical evidence suggests the physical experience is far from peaceful. That is both scientifically and morally misleading." (1)
Sharp: Is there any consciousness that BPM might be misleading?
22) BPM: "Death by nitrogen is indeed invisible and silent in itself – no blood, no smoke, no residue. But that silence masks a violent physiological response from gasping and retching to brutal respiratory distress and convulsions To call this humane is to fundamentally misunderstand how the body works.
Sharp: No it does not. We can accept BPM's physiological descriptions, while acknowledging the murderer will experience no pain, pre and post unconsciousness, while BPM must acknowledge that, as well, but have not.
23) BPM: "As policymakers and the public confront these developments, decisions must be guided not by euphemisms or convenience but by evidence."
Sharp: Agreed. It is unfortunate BPM left out some well known evidence. See Preface, as throughout.
24) BPM: "Science makes one fact clear: nitrogen itself may be quiet, but it most certainly is not kind."
Sharp: Well yes, it is used to execute, peacefully, while the murderer is unconscious.
Your article avoided all of the well known, well documented peaceful deaths, within industrial accidents, as well as the additional points that I addressed.
It wavers on impossible that BPM, accidentally, left all of that out.
In Closing
BPM wrote an anti-death penalty screed, leaving out vital information.
Again, the most important person:
Elizabeth Sennett was murdered by Kenneth Smith and John Parker, who were hired by her husband, Rev. Charles Sennett Sr. They ambushed her in her home. The murderers "blind-sided her." with a beating in which the victim apparently struggled for her life. The evidence indicated that during the beating any item within reach was used as a weapon. The men apparently used every piece of a fireplace set, a walking cane, and a piece of galvanized pipe and, after beating her, stabbed her eight times with a survival knife, in the chest, neck, face, and scalp.
How long this horror lasted and how long Elizabeth remained conscious, I could not find. Possibly, BPM will research.
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1) Silent but not serene: what science says about nitrogen death, The Conversation, 18 November, 2025,
by Damian Bailey, Professor of Physiology and Biochemistry at the University of South Wales
David Poole, Professor of Kinesiology at Kansas State University, and
Vaughan Macefield, Professor of Neuroscience at Monash University
aka BPM
2) editorial Exp Physiol. 2024 Mar 29;109(7):1009–1014. doi: 10.1113/EP091836 Death by nitrogen anoxia: On the integrated physiology of human execution
David C Poole 1,2,✉, Damian M Bailey
the Ersting (1963) are the human experiments, here:
J. Phy8iol. (1963), 169, pp. 292-311, Printed in Great Britain, THE EFFECT OF BRIEF PROFOUND HYPOXIA UPON THE ARTERIAL AND VENOUS OXYGEN TENSIONS IN MAN BY J. ERNSTING From the Royal Air Force Institute of Aviation Medicine, Farnborough, Hants. (Received 23 January 1963)
3) "Nitrogen: The Silent Killer", Josh Cable, EHS Today,Sept. 20, 2006
4) https://www.google.com/search?q=%22nitrogen+gas%22+disaster+NASA+1981+investigation&sca_esv=4c83e8cc851d4e9c&ei=pjZEafnOEcqkqtsP9LCUmAY&ved=0ahUKEwj5uYvX0ceRAxVKkmoFHXQYBWMQ4dUDCBE&uact=5&oq=%22nitrogen+gas%22+disaster+NASA+1981+investigation&gs_lp=Egxnd3Mtd2l6LXNlcnAiLyJuaXRyb2dlbiBnYXMiIGRpc2FzdGVyIE5BU0EgMTk4MSBpbnZlc3RpZ2F0aW9uMgUQIRigATIFECEYoAEyBRAhGKABSLGjAVDyCFj1ngFwBXgAkAEAmAH9AqAB0DyqAQk1LjE2LjExLji4AQPIAQD4AQGYAiigAu01wgIOEAAYgAQYsAMYhgMYigXCAgsQABiABBiwAxiiBMICCBAAGLADGO8FwgIFECEYqwKYAwCIBgGQBgWSBwg2LjE5LjguN6AH1cMBsgcIMS4xOS44Lje4B7k1wgcGMi0zMi44yAf6AYAIAA&sclient=gws-wiz-serp
5) Hong Kong Journal of Emergency Medicine, Asphyxia due to accidental nitrogen gas inhalation: a case report, F Çalkan Tür and E Aksay, 2012;19:46-48
The media/academic norm is to use anti-death penalty material, refuse to fact check or vet it and avoid all pro-death penalty research and experts or to pretend that is the case. How will you know that is true? Read on:
a) The Death Penalty: Justice & Saving More Innocents
and
b) Students, Academics & Journalists: Death Penalty Research
(7 pro-death penalty experts are included)
c) 600+ pro death penalty quotes from murder victim's families &
3300+ from some of the greatest thinkers in history
7) Hippocratic Oath is within
The Death Penalty: Medical Ethics Revisited
8) 30 Examples: How Death Penalty Abolitionists Value Murderers
More Than Their Innocent Victims:
AKA - Full Rebuttal of Sir Richard Branson & His Death Penalty Comments
9) The Death Penalty: Saving More Innocent Lives
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