Anoxia
Total absence of oxygen as the
principle of the N2GF technology
For more information: www.n2gf.com

Index
Part 1 Anoxia
Part 2 Killing and slaughter within the European framework
Directive EU 1099/2009
Part 3 Killing and the slaughter of animals using nitrogen foam
Part 4 Research projects
Part 5 Conclusions
For more information: www.n2gf.com 2

Part 1
Anoxia
For more information: www.n2gf.com 3

Anoxia, Hypoxia and Hemoglobin
• Anoxia is the condition characterized by complete absence
(or almost complete absence) of oxygen supply to the brain
• Hypoxia is the condition is characterized by insufficient
oxygen supply to the brain
• Hemoglobin protein in red blood cells which plays a crucial
role in the transportation of oxygen and other gasses
throughout the body
For more information: www.n2gf.com 4

Five types of Anoxia
• Hypoxemic anoxia – high altitude
– Hypoxemic anoxia can happen during deep sea diving or at high altitude, when the
oxygen pressure outside the body is so low that hemoglobin in the red blood cells is
unable to absorb sufficient oxygen.
• Anemic anoxia - accident
– Anemic anoxia results from a decrease in the amount of hemoglobin in the blood, which
reduces the ability to get oxygen to the tissues, caused for instance by blood loss
(hemorrhage)
• Affinity anoxia – blood failure
– Affinity anoxia involves a defect in the chemistry of the blood such that the hemoglobin
can not release oxygen
• Stagnant anoxia – heart disease
– Stagnant anoxia occurs when the blood flow is blocked, although the blood and its
oxygen-carrying abilities are normal
• Histotoxic anoxia – narcotics and alcohol
– Histotoxic anoxia can also be caused by exposure to narcotics, alcohol etc.
For more information: www.n2gf.com 5

The function of hemoglobin
Hemoglobin plays a crucial role in the transport of gasses:
• Hemoglobin is the iron-
containing oxygen-transport
metalloprotein in the red blood
cells of all vertebrates
• Hemoglobin in the blood carries
oxygen from the respiratory
organs (lungs) to the rest of the
body where it releases the
oxygen
For more information: www.n2gf.com 6

Never heard about Anoxia?
• In a plane you are instructed what to do in
case the cabin pressure drops ..
• In case you would climb the Mount Everest,
you need additional oxygen, unless you are
a Sherpa ..
• In case you are diving, you are instructed
what to do when you dive below 30 meters
..
For more information: www.n2gf.com 7

So, if oxygen isn’t transported to the lungs,
what kind of gasses are transported instead?
– Oxygen must be present in every breathing gas
because it is essential to the human body's
metabolic process
– As the altitude increases (from > 2,400 meter)
atmospheric pressure decreases, oxygen levels drop
– At 30 meter below sea-level, the pressure raises to
the level of 4x the normal atmosphere, leading to
higher CO2 and lower Oxygen levels.
– Decrease of the oxygen level in the blood leads to
relative increase of the nitrogen concentration
inhaled, resulting in Hypoxic Anoxia
– In the medical literature, the effects of exposure to
high concentrations of nitrogen is described as
Nitrogen Asphyxiation
For more information: www.n2gf.com 8

Nitrogen Asphyxiation and its effects
• Nitrogen asphyxiation is a medical condition in which a person dies from
hypoxemic anoxia because the nitrogen concentration in his body is too
high
• When such asphyxiation begins, it only takes several breaths until it affects
the body’s oxygen supply: 1 minute of nitrogen exposure may cause a
person to fall unconscious and die in less than 10 minutes
• Until nitrogen exposure reaches a dangerous level, most persons don’t feel
stress or pain. Dying from high level nitrogen happens without warning or
immediately noticeable effects, unlike when a person dies from carbon
monoxide or carbon dioxide asphyxiation (they typically will become dizzy
and feel pain before dying).
For more information: www.n2gf.com 9

Example:
Nitrogen asphyxiation and diving
• Underwater, a diver must deal with two major issues: pressure and temperature. Pressure
affects the amount of nitrogen and oxygen gases that dissolve in the blood and tissues
• Atmospheric air is a mixture of 21% oxygen and 78% nitrogen. When a person inhales air, the
body does nothing with the nitrogen: it only consumes the oxygen and replaces some of it
with carbon dioxide
• When a diver descends under the water, the pressure on his body increases, so more
nitrogen and oxygen dissolve in his blood. Most of the oxygen gets consumed by his tissues,
but the nitrogen remains dissolved
• When a diver reaches depths of about 30 m or more, he experiences a feeling of euphoria
called nitrogen narcosis: the nitrogen partial pressure reaches high levels, causing the
replacement of oxygen by nitrogen in the blood
• Nitrogen narcosis can impair the divers judgment, make him feel relaxed or even sleepy
• Narcosis comes on suddenly and without warning and when its not detected by a buddy
diver, it leads to drowning of the diver
For more information: www.n2gf.com 10

Part 2
Killing and slaughter within the European framework
Directive EU 1099/2009
For more information: www.n2gf.com 11

Killing and slaughtering animals
According to Directive EU 1099/2009
• Directive EU 1099/2009 is valid for all situations where
animals are killed or slaughtered:
– slaughtering of animals at the slaughter house
– mass culling during outbreak situations
– Killing of sick and crippled animals on the farm
• Basic principle: manually killing of animals is not allowed as
primary killing method
• Only 4 general types of killing techniques are allowed
For more information: www.n2gf.com 12

General types of
killing techniques (1)
1. Mechanical methods
– Penetrative captive bolt device
– Non-penetrative captive bolt device
– Firearm with free projectile
– Maceration
– Cervical dislocation
– Percussive blow to the head
2. Electrical methods
– Head-only electrical stunning
– Head-to-Body electrical stunning
– Electrical waterbath
For more information: www.n2gf.com 13

General types of
killing techniques (2)
3. Gas methods (hypoxia, hypoxemic anoxia, anoxia)
– Carbon dioxide at high concentration
– Carbon dioxide in two phases
– Carbon dioxide associated with inert gases
– Inert gases
– Carbon monoxide (pure source)
– Carbon monoxide associated with other gases
4. Other methods
– Lethal injection (T61)
For more information: www.n2gf.com 14

Category 3:
Gas methods
A. Hypoxia – CO2
A. Hypoxemic Anoxia – CO2 + Argon
A. Anoxia – Nitrogen
For more information: www.n2gf.com 15

A: Hypoxia
• Most common gas method: Carbon dioxide
• CO2 in high concentration
• minimum concentration for poultry: > 40%
• Minimum concentration for pigs: > 80%
• Applied in various situations
• Containers
• Pits
• Tunnels
• Sealed-off buildings
• Various forms
• Compressed gas in Bottles
• Liquid gas in bulk tanks
• Dry ice
For more information: www.n2gf.com 16

Hypoxia and the
effects on animals
• Animals are placed in a room (container/pit/tunnel or in a sealed off
building) that is flooded with CO2 that is heavier than air and cold (the
temperature of solid CO2 -dry ice- is -78C)
• With the raise of the CO2 level, the oxygen level in the room is deprived
• The animals notice that they are dying
• The animal is slowly but steadily confronted with lack of oxygen the
animals react before being unconscious by head shaking (heavy breathing)
and convulsions (lack of control over their nerve system)
• Some animals react to the raising level of CO2 by withholding their breath
as long as possible or try to climb to the highest point in the room
• The animals die by the effects of hypoxia
For more information: www.n2gf.com 17

B: Hypoxemic Anoxia
• Most common gas combination: Carbon dioxide + Argon
• Mixture of different gasses
• minimum concentration for poultry: < 40% CO2
• Minimum concentration for stunning pigs: > 30% CO2 within 7 minutes max
• Minimum concentration for stunning poultry: > 30% CO2 within 3 minutes max
• Applied in various situations
• Containers
• Pits
• Tunnels
• Sealed-off buildings
• Various forms
• Compressed gas mixtures in Bottles
• Liquid gas mixtures in bulk tanks
For more information: www.n2gf.com 18

Hypoxemic Anoxia and the
effects on animals
• Animals are placed in a room (container/pit/tunnel or in a sealed of
building) that is flooded with a mixture of CO2 + Argon
• In some cases, additional oxygen is added in the first minute to stimulate
the animals to maintain their breathing
• The animals notice that they are dying
• Like with pure CO2, the animal is slowly but steadily confronted with lack
of oxygen. The animals react before being unconscious by head shaking
(heavy breathing) and convulsions (lack of control over their nerve
system)
• Because of the gas mixture and the lower concentration of CO2, the lungs
are filled with a high concentration of Argon
• The animals die by the effects of hypoxic anoxia
For more information: www.n2gf.com 19

C. Anoxia
• Techniques based on the exposure
concentration of more than 95% nitrogen
– Applied in gas chambers floated with high
concentrations of nitrogen
– Applied in high expansion foam: the N2GF
Method
For more information: www.n2gf.com 20

Anoxia and the
effects on animals
• Animals are placed in a room (container/pit/tunnel or in a sealed of
building) that is flooded with gas foam, containing a concentration of
>95% Nitrogen
• The reaction of the animal to being submerged in foam is minimal
• The total absence of oxygen stays unnoticed
• The animals do not notice that they are dying
• Unlike hypoxia and hypoxic anoxia, the animals don’t react by head
shaking or perform convulsions prior to their unconsciousness
• After the animals are unconscious, their body reacts with convulsions
caused by the lack of control in the nerve system
• The animal dies after being submerged in the foam for 1,5 to 2 minutes
For more information: www.n2gf.com 21

The three slaughter principles compared
• Hypoxia and Hypoxic anoxia methods:
– Large quantities of gas are needed to reach the gas level needed to
slaughter/kill the animals
– During the process of filling the room with gas, the animals notice that
the oxygen level slowly but steadily deprives
– Animals react prior to reaching the state of unconsciousness and their
reaction on the presence of CO2 (or a combination of CO2 and Argon)
• Anoxia methods:
– Only a fraction of nitrogen (compared to CO2/combination of
CO2+Argon) is needed to create an atmosphere of >95% nitrogen
– The animals don’t notice that they are in the process being killed or
slaughtered
– The animals are killed without any additional stress or pain caused by
the slaughter process
For more information: www.n2gf.com 22

Part 3
Killing and slaughtering animals
using nitrogen foam
For more information: www.n2gf.com 23

Directive EU 1099/2009
on slaughter by Anoxia
The European Union described Anoxia as an accepted gas method
(category 3) for the slaughter of poultry and pigs:
• ANNEX I - LIST OF STUNNING METHODS AND RELATED SPECIFICATIONS (as
referred to in Article 4) CHAPTER I - Methods – table 3 – under 4:
• Name: Inert Gas
• Description: Direct or progressive exposure of conscious animals to a inert gas
mixture such as Argon or Nitrogen leading to anoxia. The method may be used in
pits, bags, tunnels, containers or in buildings previously sealed
• Conditions of use: Pigs and poultry – slaughter - depopulation and other situations
For more information: www.n2gf.com 24

Animals and nitrogen foam?
• Animals hardly show any stress reaction when they are submerged into
the foam:
– Touching the foam does not hurt
– Nitrogen is odorless and tasteless
– Foam is colorless
• As soon as the head of the animal submerges, it is exposed to a mixture of
> 95% nitrogen and <5% oxygen
• The first 20 – 25 seconds after being submerged, the animals still don’t
notice the absence of oxygen
– They maintain their normal breading
– They don’t show any muscle contractions
• After 20 to 25 seconds, the animals renders unconscious, resulting in the
start of the muscle contractions
• After 1 to 1,5 minutes, the high concentration of nitrogen in the blood
produces heart failure and mortality.
For more information: www.n2gf.com 25

Description
nitrogen foam equipment
The standard equipment is attached
to the wall and consists of:
1. A nitrogen gas cylinder, including hoses
and a regulator
2. A pressure vessel for water and soap
mix, including water hoses
3. A foam nozzle in which nitrogen and
the water/soap solution are mixed
4. Measuring and control equipment to
monitor the gas concentration and
temperature
5. A standard barrel or container that is
filled with the nitrogen gas foam.
For more information: www.n2gf.com 26

Components
Foam nozzle
Water and foaming agent
Nitrogen
High expansion foam
For more information: www.n2gf.com 27

Benefits for farmers
• The nitrogen gas foam method is easy to integrate into procedures on the
farm, and given the absence of unnecessary pain and suffering, it is the
most humane killing method available
• Both the initial investment and operating costs are very low
• Stunning and killing of animals (pigs and poultry) by anoxia is accepted
according to the EU directive EU 1099/2009
• The direct involvement of the operator performing the killing of the
animals and the effect on him are minimized: low risk of error or failure -
minor psychological stress - low physical load
• The method is safe. The operator needs only to assure that his nose and
mouth are not in direct contact with the gas foam.
For more information: www.n2gf.com 28

Simplified description of the standard procedure
to kill animals with nitrogen gas foam
The operator starts the procedure to produce the nitrogen foam:
• controls water and soap in the pressure vessel - checks gas reserves in the
nitrogen bottle - starts the foam production - places the cadaver barrel
below the foam nozzle - controls temperature and nitrogen concentration
in the foam
• makes his rounds through the stables and selects weak and sick animals
• removes these animals from the stable and transports them to the
cadaver barrel
• allows the animals one-by-one carefully through the top layer of the
nitrogen foam into the barrel at intervals of 2 minutes
• After all sick and weak animals are killed, the the cadaver barrel is closed.
The nitrogen foam dissolves completely in the course of time and the
concentration of nitrogen in the barrel easily disappears into the
atmosphere.
For more information: www.n2gf.com 29

Special features
• Simplicity: control, cleaning and disinfection
• Cost effective: Low initial investment. Operational costs are very
low: only water, soap and nitrogen
• Stability of the foam: upper layer of foam (at least 40 cm) ensures
that the concentration of nitrogen that is located beneath the foam
layer remains high, in spite of the convulsions of the animal. The
nitrogen can not escape. Even during the time that the animal falls
through the upper foam layer, the concentration of nitrogen
remains intact
• Safety: nitrogen is an atmospheric gas - non toxic - safe to transport
- the soap has no adverse effects on humans and the environment
• Animal welfare: animal dies within 1.5 to 2 minutes as a
consequence of the absence of oxygen
For more information: www.n2gf.com 30

Part 4
Research projects
Opinion of leading animal scientists on
Hypoxia and anoxia as slaughter technique
For more information: www.n2gf.com 31

Anoxia
Scientific research projects
Overview resent research projects (from 2006 until today) on Anoxia and
slaughter:
• Dr. Marien Gerritzen (Anoxia caused by nitrogen foam)
• Dr. Dorothy McKeegan (Anoxia caused by nitrogen foam)
Overview resent research projects on Hypoxemic anoxia:
• Dr. Mohan Raj (Hypoxemic anoxia by a gas mix of CO2 and argon)
For more information: www.n2gf.com 32

Dr. Marien Gerritzen
WUR University of Wageningen
Summary, page 11:
‘The use of high expansion gas-filled foam
containing CO2 or an Anoxic gas such as
Nitrogen presents a feasible alternative
delivery method of hypercapnic or anoxic
killing, because as the foam envelopes the
bird, oxygen will be effectively eliminated and
or carbon dioxide will be effectively presented
and birds will die by hypercapnic-anoxia or by
anoxia.’
For the full text of the report, visit www.N2GF.com
For more information: www.n2gf.com 33

Dr. Dorothy McKeegan
University of Glasgow,
College of Medical, Veterinary & Life Sciences
Presentation: Gasfoam - a humane
agent? (Oct ‘11), conclusions, page 10:
‘Collectively, the results show that
anoxic foam has the potential to be a
reliable and humane method of
emergency killing for poultry.’
For the full text of the report, visit www.N2GF.com
For more information: www.n2gf.com 34

Dr. Mohan Raj
Bristol University,
Bristol Veterinary school
HSUS Report: The Welfare of Birds at
slaughter - Conclusions - page 8:
Comparing electrocution and hypoxemic
anoxia using a mixture of CO2 and Argon:
‘After a comprehensive review of the
scientific literature, the Scientific Panel on
Animal Health and Welfare, an official
advisory body to the European Commission,
(EFSA) stated:
Since welfare is poor when the shackling line
and water bath electrical stunning method is
used, and birds are occasionally not stunned
before slaughter, the method should be
replaced as soon as possible. At present, the
inert gas stun/killing method is the best
alternative.’
For more information: www.n2gf.com text of the report, visit www.N2GF.com
For the full 35

The technique
behind the N2GF method
The N2GF technique is based on the principle of Anoxia:
– High expansion foam bubbles are created, using a nozzle
– The water/soap mix is composed by 95% water and 5% soap
– The foam bubble is filled with >95% nitrogen
– The animals are covered with a layer of foam
– Form one moment to the other, the animal is confronted with the total
absence of oxygen without noticing
– The animal stays completely calm and doesn’t show any convulsions
until its unconscious. From that moment on, the convulsions start
– After being unconscious, the animal dies, caused by Anoxia
For more information: www.n2gf.com 36

scientific research
based on applying the nitrogen foam technique
• Since January 2013, the research on applying the technique is
conducted at the Pig Innovation Center VIC Sterksel, part of WUR
Wageningen University in Holland
• The research concentrates on how the technique can be applied as
general technique on pig and poultry farms
• Following the results, the research will be expanded to the possible
application on other animal species
• Based on the results, special tools will be developed and tested so
that the technique can be applied easily within the daily routines on
the farm
• The introduction will be completed by an online and vocational
training module, including certification for the users
For more information: www.n2gf.com 37

Part 5
Conclusions
For more information: www.n2gf.com 38

Conclusions
• The gas foam technique is the only universal killing technique,
because it is based purely on Anoxia
• Killing and slaughtering with gas foam does not create
additional stress or pain
• The influence of humans is minimalized using gas foam
• Gas foam is efficient and (cost) effective and cheap to apply
• Gas foam can be applied on single (sick and injured) animals
on the farm, as well as to large numbers of animals during
outbreaks of diseases
For more information: www.n2gf.com 39