Applying Firefighting Foam for Depopulation.pdf

Applying high expansion firefighting foam for depopulation purposes
Confidential Page 1 3/13/24
Applying Compressed Air Firefighting Foam for Depopulation
“The World Organization for Animal Health (WOAH) defines animal welfare as the
holistic well-being of an animal considering both its physical and mental state in
relation to its living and dying conditions. As an expert in this field, this definition
serves as the foundation for devising methods to humanely euthanize animals during
crisis scenarios.
I have significant concerns about the potential normalization of using water-based
Compressed Air Foam (CAF) as a regular method to euthanize large numbers of farm
animals by suffocation in highly stressful situations. My viewpoint emphasizes the
necessity of categorizing animals into two groups: infected and non-infected.
It is crucial to prioritize the handling of non-infected animals by establishing temporary
processing centers within restricted transport zones. The welfare of these animals
should mirror or exceed the standards observed in conventional slaughter facilities.
Conversely, infected animals must be swiftly depopulated, potentially involving the use
of air-based CAFs in emergency situations arising not due to lack of preparation or
investment.
I believe it is the responsibility of the AVMA (American Veterinary Medical Association)
to establish legislative guidelines that differentiate between these categories,
preventing the unnecessary suffering and euthanasia of healthy animals.”
Harm Kiezebrink MBA
Subject matter expert
and Independent Program Manager
Sweden: +46 70 29 45 334
Harm.kie@gmail.com

Executive Summary:
The Livetec technology, based on using Compressed Air Foam (CAF) for depopulating pigs,
emerges within a critical landscape. The complexities of implementing effective emergency
depopulation strategies for livestock, particularly swine, present multifaceted challenges.
Livetec's approach relies on high expansion firefighting foam, aiming to euthanize pigs by
submerging them in foam.
The evaluation highlights numerous issues surrounding CAF technology. Firstly, the identified
concerns about using firefighting foam for purposes other than fire suppression emphasize
the need for a thorough understanding of its chemical properties and associated risks.
Specifically, the stress caused to animals and the challenges in effectively administering foam
due to animal movements raise significant animal welfare and practicality concerns.
Moreover, the application of medium-expansion CAFs, despite its potential feasibility in
covering floor-reared poultry, faces limitations in effectively euthanizing pigs. The inability to
achieve desired expansion rates, leading to insufficient foam coverage and potential occlusion
of the trachea rather than a humane euthanization process, diminishes its credibility as a
viable method for pig depopulation.
The Livetec system's claims about the effectiveness of nitrogen-filled high expansion foam for
depopulating market pigs lack substantial evidence upon analysis. The discrepancy between
the actual foam produced during field trials and the promised high expansion foam, coupled
with the absence of concrete proof supporting the method's efficacy, discredits the
technology's claims.
Overall, the Livetec technology's purported advantages in depopulating pigs using CAF,
especially in terms of animal welfare and practicality, are called into question due to the
complexities, costs, and impracticalities revealed through analysis and field trials. The lack of
evidence supporting its effectiveness and concerns regarding animal welfare suggest that
employing CAF for pig depopulation should be approached cautiously and critically evaluated
before widespread adoption.
Audience
The report is intended for welfare specialists and experts involved in evaluating novel
depopulation techniques. It aims to provide background information on the use of high
expansion foam technology and its potential application for the humane and efficient killing
of farm animals.

Reference
The report features general information provided by the producers of high expansion
firefighting foam and the personal experiences of the author who has been involved in
developing alternative stunning methods and techniques during the past 25 years, with
hands-on experience as executive crisis manager during more than 2.000 outbreaks, and as
international advisor, and trainer for various UN organizations.

Overview
Executive Summary: ...................................................................................................2
Audience .................................................................................................................2
Reference ................................................................................................................3
Overview..................................................................................................................4
1. Introduction..........................................................................................................6
2. History of using Compressed Air Foam for depopulation purposes ...................7
The technical- and physical properties of high expansion foam ............................9
Applying Water Based Compressed Air Foams - CAFs for Combatting Fire..........9
3. Applying Water Based Compressed Air Foams - CAFs....................................11
Initial research: Bud Malone, University of Delaware............................................11
Low- and Medium- expansion CAFs .....................................................................11
Additional research: Using CAFs for large-scale depopulation purposes............11
Technical factors influencing foam production .....................................................12
Experiment 1: Applying CAFs in different size poultry barns................................12
Calculations of Actual Expansion Rates – Total Fluid Usage – total Concentrate
Usage ....................................................................................................................13
Total Fluids Usage Experiment 1...........................................................................13
Results Total Fluid Volume in m3
...........................................................................13
Results Total Foam Concentrate in liters...............................................................14
Experiment 2, applying CAFs in 30,5 m3
commercial trash dumpster..................14
Disposal of the discharged foam and wastewater................................................14
3. Killing Poultry by Inhaling CAF ..........................................................................16
Stratification of the foam and other technical obstacles .......................................17
4. Killing Pigs by Inhaling nitrogen-filled High Expansion Foam...........................19
Introduction: Applying the Livetec technique during the field trials......................19
Validation of the Livetec Systems Nitrogen Foam Delivery System (NFDS) .........19
Loading norm ........................................................................................................20
Dimension of the containment...............................................................................20
Technique and capacity........................................................................................20
Technical foaming procedure ...............................................................................20
Setting of the NFDS foaming system capacity per volume/hour/minute...............20
Water and foam concentrate consumption ...........................................................20

Volume capacity to fill the containment with foam ................................................21
Filling time per containment ..................................................................................21
Foam production in reality under field circumstances ..........................................21
Table: Range of foam properties at continued foaming........................................22
Comments on the observations during the study..................................................22
5. Opinion of the author .........................................................................................23
Vulnerability of high expansion foam.....................................................................24
Main Points in the US Pork Board's Validation Report ..........................................25
Cessation of Movement, Los of Posture, Loss of Consciousness.........................25
Water-based CAFs as last resort method for depopulating pigs..........................27
Conclusion.............................................................................................................27

1. Introduction
Many firefighting foams are developed for the purpose of for fire suppression of fossil fuels. Its
role is to cool the fire and to coat the fuel, preventing its contact with oxygen, thus achieving
suppression of the combustion.
In 2006, firefighting foam was used for the first time for the purpose of depopulating large
quantities of poultry, quickly, economically viable, without direct contact between animals
and humans.
The first applications of this new method involved the same technique as for its original
purpose: a blanket of mid-expansion foam is rolled over poultry, inside the barn.
An improved version of this technique was developed by Kifco Inc, Havana Illinois, in close
cooperation with Professor dr. Eric Benson and dr. Bud Malone of the University of Delaware,
USA. Their approach, placing large firefighting foam generators in various compartments
within the barn, has been accepted by the AVMA i
, and temporary approved by the US
veterinary authorities, based on its effectiveness of killing quantities of poultry.
The Compressed Air Foam method -CAF- has since been used as an alternative method to
mass depopulate floor-reared poultry as an alternative to carbon dioxide stable gassing,
especially in cases that the type of barn was not suitable for the latter method.
The primary goals of this technology are to terminate animals efficiently at a minimal cost
with a 100% success rate. Although animal welfare principles, human handling and
depopulation techniques should be employed on the basis of scientific evidence, the AVMA
does not venture into the morality of killing animals during depopulation. Therefore, animal
welfare has not the same level of priority as it has within the European Union.
The CAF technology utilizes low expansion foam that effectively blocks the trachea of the
animals, creating an effective and efficient way to kill birds. No rigorous behavioral studies on
the impact to animal welfare have been reported.
Furthermore, during the presentationii
of Class A high expansion foam, the foam concentrates
were presented as a substance, similar to soap, and the foam quality similar to shaving foam.
Unless the chemical content of the foam agent has been assessed on the toxicity of its
components, the assertion that CAFs is as innocent as soap or shaving foam don’t pose
environmental risks at the application site is unsubstantiated.
Low expansion CAFs contain a significant amount of water, making them impractical to use in
freezing conditions.
It is crucial to relate manufacturers’ claims of the safety of their firefighting products to their
use as firefighting foam, and not for depopulation of large numbers of poultry or other farm
animals.

When CAFs are used for this alternative purpose, policy makers, veterinarians, emergency
responders and farmers need to have a better understanding of the chemical properties of
firefighting foam to grasp the occupational health- and environmental risks associated with
its extensive use in concentrated areas.
2. History of using Compressed Air Foam for depopulation purposes
The United States relies heavily on its poultry and pig supply chains as crucial components of
the nation's agricultural sector. The pig industry spans around 60,000 to 65,000 farms
nationwide, while the expansive poultry industry involves numerous large-scale farms.
A significant portion of these pig farms operates through vertically integrated systems,
managed by a single entity across various production stages. Sometimes, the breeding phase
occurs in Canada, followed by growth phases in the U.S.
Large farms using indoor housing pose the challenges owing to a large number of pigs on the
site, as well as the presence of slatted floors and deep manure pits. These features make
some euthanasia methods non-feasible and present significant challenges to post-death
handling and disposal.
Similar to all intricate agricultural systems, the U.S. pork supply chains are susceptible to
internal and external threats. These threats include disease outbreaks, natural disasters,
supply chain disruptions, and economic challenges. It's crucial to implement comprehensive
response plans to mitigate these vulnerabilities effectively.
A primary concern for these sectors involves potential incursions of foreign diseases such as
African Swine Fever (ASF), Foot-and-Mouth Disease (FMD), and salmonella infections. These
diseases can devastate swine herds, disrupting supply chains and causing significant
economic losses. Prompt and efficient responses are essential to contain disease outbreaks
and minimize their impact on the industry.
Acknowledging the urgent need for development of rapid mass depopulation procedures for
the purpose of killing pigs during emergency situations, various groups of experts and
specialists have tried to develop methods for depopulation of pigs over the past 30 years.
Despite research over these three decades, a safe and reliable way to induce rapid
unconsciousness and death in larger populations of swine did not emerge.
Systematic literature review
The absence of a safe and reliable mass depopulation method for swine is one of the main
conclusions of an extensive study, recently published in Nature at November 20, 2020, by
Arruda et al (Ohio State University): A Systematic Literature Review on Depopulation

Methods for Swineiii
. Arrura et al summarized the applicability of different techniques for
depopulation of large numbers of pigs and highlighted critical gaps in knowledge.
One of the major findings is that there is a small number of studies on mass depopulation of
pigs, but that the available reports are inconsistent in describing main characteristics of
depopulation methods, and most assume a scalable process based on small sample sizes.
The literature review revealed subjectivity and a lack of standardization in determining crucial
factors like time to death. This lack of consistency, combined with different methods used
across studies, reduced the possibility of direct comparisons among the 18 studies reviewed.
Only half of these studies clearly defined how unconsciousness was measured, and just 60%
provided a clear description of welfare-based assessments. Even within this 60%, the
assessments varied significantly, ranging from expert perception and animal behavior to
stress indicators and physical reactions. This variability hindered the ability to compare
outcomes across the studies effectively.
Inhalation of CO2
Inhalation-based depopulation using gaseous CO2 was the most commonly investigated
method in this review. This was not surprising given there is a substantial body of literature
supporting the uses of CO2 for slaughter stunning in pigs. However, it is very important to note
that meat-packing CO2 systems are designed based on research findings under controlled
conditions within a plant, whereas on-farm depopulation scenarios are considered highly
variable due to extraneous factors.
In addition, distress, aversion, and escape behaviors in response to the presence of a high
concentration (greater than 50%) of CO2 in the air indicates that CO2 can compromise pig
welfare due to air hunger, fear, anxiety, and pain.
Inconsistencies in CO2 research
There is evidence of CO2 causing direct painful sensation through the trigeminal nerve in
humans as well as other experimental animal models. However, researchers have not
consistently observed this effect, and some found CO2 concentrations as high as 90% to be
considerably less aversive than electrocution.
The variations observed could be due to varying gas concentrations, the age of the animals,
duration of gas exposure, genetic diversity among the animals studied, and the specific
behaviors examined. For example, certain breeds displayed higher aversion to 90% CO2 in one
test, but in another trial by the same researchers, the difference was attributed to individual
animal temperament rather than the breed itself.
Studies commonly explored combining CO2 with inert gases like argon, showing promise in
lessening the aversive effects of CO2 when used alone.

Availability and costs of CO2
Several limited studies primarily centered on equipment design but also touched on various
practical issues. Periodic shortages of liquid CO2 not only affect costs but also restrict the
access to large quantities during emergencies as gas companies prioritize their regular clients.
Similarly, the lack of logistical infrastructure to convert CO2 into its required gaseous form
presents critical challenges for employing these techniques. Ultimately, constructing a
national depopulation strategy based on CO2 utilization is not viable.
Applying Compressed Air-filled foam CAF for depopulation purposes
Various methods, including the use of water-based Compressed Air Foam (CAF), have been
suggested and assessed through field studies for practicality and effectiveness, although
according to the review of Arruda et al, there are no reports for their uses on pigs.
The use of CAFs has been reportediv
to be effective in the depopulation of large numbers of
caged layer hens, but the AVMAv
allows CAF-based methods for poultry in constrained
circumstances only, but does not approve CAF for pigs.
Arrura et al concluded that none of the published studies demonstrated the existence of an
ideal, reliable, and safe technique to induce rapid unconsciousness in large groups of pigs
during depopulation. It is therefore understandable that recently developed techniques,
developed in Europe, would be subject to research on its applicability under practice
conditions. Two of these techniques are based on the use of high expansion foam, filled with
gas.
Therefore, prior to approving CAF as a technique for depopulating pigs, field trials are needed
to assess its effectiveness. In this report various publications are assessed that describe the
application of water-based firefighting CAFs as potential depopulation technique.
Upon approval, specific terms, conditions, and technical guidelines should be integrated into
emergency management and control plans. Training programs should also include the safe
and humane execution of this technique.
The technical- and physical properties of high expansion foam
Using firefighting foam to kill animals during emergency situations comes with additional
uncertainness and possible extra risks, depending on factors like the type of foam used, how
much water is used, the temperature in the surroundings, and concerns about too much
foam in closed spaces with sensitive equipment that can get rusty. It also involves dealing
with wastewater that has high levels of foaming agents, with a high oxygen demand and
foam accumulation in sewage treatment plants. .
Applying Water Based Compressed Air Foams - CAFs for Combatting Fire
In the mid-1980s, water-based compressed air foams (CAFs) were created for the purpose of
combating wildfires. Compressed air foams with an expansion rate of < 20:1 work by reducing

the natural resistance of water, making it easier to soak and saturate flammable materials
with water. They can reach deep into the fire to put out smoldering embers, thus helping to
control the fire and avoid it flaring up again.
There are three different techniques to apply CAFs:
• Sweep (roll-on) method
This method is used on a pool of flammable product on open ground, directing the foam
stream onto the ground in front of the product involved
• Bankshot (bankdown) method
The Bankshot method is used on objects to deflect the foam stream so it flows down the
burning surface, allowing the foam to spread over the material and form a foam blanket
• Raindown method
The Raindown method is only used when it is not possible to employ the Bankshot method
or the Roll-on method.
Water-based CAFs are effective as long as the foam stream completely covers the material
but might not be effective if wind or weather conditions are unfavorable.

3. Applying Water Based Compressed Air Foams - CAFs
Initial research: Bud Malone, University of Delaware
After the large-scale outbreak of HPAI in Europe in 2003, Dr. Bud Malone et al (University of
Delaware) started to develop alternative methods for mass depopulation of poultry. A team of
scientists from the University of Delaware identified a number of complicating factors for
mass emergency depopulation, including a lack of personnel with emergency depopulation
experience, emotional and physical fatigue, finding and training temporary employees,
communicating with employees who were not native English speakers, maintaining employee
morale, employee safety, biosecurity, time pressure, and a lack of proven humane and
efficient emergency depopulation methods.
Benson et al developed applications to apply water-based CAFs for mass depopulation of
poultry, and presented their results in the publication “Foam-Based Mass Emergency
Depopulation of Floor-Reared Meat-Type Poultry Operations” on March 2007 in Poultry
Science.
Low- and Medium- expansion CAFs
Applying low-expansion CAFs was first recognized as an option to quickly mobilize existing
firefighting capacity that would make it possible to carry out a number of depopulation
operations simultaneously. The prospect of reducing the labor and possible exposure to the
virus, less physical and mental distress, reducing the bio security risks, a fast death and the
prospect of in-house composting of carcasses were promising, but the limited expansion
ratio of <20:1 of low-expansion CAFs appeared to be insufficient to guarantee a foam blanket
to cover the poultry under all possible circumstances.
Medium expansion CAFs seemed to be more feasible and practical option to kill large
numbers of floor-reared poultry. Medium expansion CAFs have an expanding ratio varying
from 50:1 to 250: 1. This should in theory be sufficient to create a foam blanket with larger
bubbles, what makes it easier to quickly and effectively cover animals raised on the floor up
to a certain height with foam.
Medium expansion CAFs also includes the ability to use specific gases to expand the bubbles,
including properties to stun and kill animals, such as carbon dioxide, nitrogen, or argon. For
this purpose, specific nozzles were developed to produce medium-expansion CAFs.
Additional research: Using CAFs for large-scale depopulation purposes
In an article titled ”Implementing water-based foam depopulation of floor reared poultry”,
published by Shailesh Gurung et al on September 23, 2017 in the Journal of Veterinary
Medicine and Research, the results of two technical experiments of creating CAFs using

different foam production techniques and different foam agents are used that could be
considered for depopulation of poultry.
This technical study (no actual poultry was used) examined the processes of using CAFs as a
depopulation method that could be applied on large poultry populations, in two different test
settings. In the first setting, they looked at how well it worked in bigger poultry barns. In the
second setting, they studied how to use containers for this purpose.
Technical factors influencing foam production
The foam generator is said by the manufacturer to have a 100:1 expansion ratio, while the
nozzle has a 60:1 ratio. Both ratios comply with USDA guidelines for floor-raised poultry.
However, experiments revealed various factors that notably decrease the real foam expansion
rate. These factors encompass the foam concentrate type, foam layer height, barn width,
nozzle selection, and generator operation method. This discovery holds significance as the
expansion rate directly impacts the required quantities of water and foam agent in
operations.
The foam's expansion rate, ER, varied based on the equipment used. Foam generators caused
faster expansion than air aspirating nozzles. Normally, the longer the system ran, the better
the foam expanded. Yet, in wide poultry barns, foam expansion slowed down. To fix this, an
extensional air aspirating nozzle was added to the foam generator cart. This helped spread
the foam effectively toward the barn's outer edges for efficient operation.
Experiment 1: Applying CAFs in different size poultry barns
Experiment 1 utilized a Kifco Avi-Foam Guard AV- ST3 IRR depopulation system for foam
production, testing various commercially available foam concentrates like Ansul Silvex, ICL
Performance Products Phos-Chek First Response, and Phos-Chek WD881, with foam
concentrate maintained at 1%.
Large broiler barns are typically 12.5 m x 153 m in size. As a result of economies of scale the
poultry industry has shifted toward larger barns. Broiler barns built recently are usually 20.1 x
183 meters, whereas turkey barns can reach up to 28.0 m x 280 m in size. The majority of the
foam generating system's testing and development took place in smaller, older barns. For
these experiments penning has been utilized to split the barn lengthwise, and foaming is done
from each end.
Two distinct open-air pens, one 15.3 m wide x 62.3 m long and one 23.7 m wide x 62.3 m
long, were constructed on level soil together with 0.9 m silt fence. The pen lengths were set to
allow the system to reach the optimal operating configuration while avoiding side effects
caused by starting and halting of the foam production process. The foam generators were
utilized to fill the pen from the back wall forward.

Calculations of Actual Expansion Rates – Total Fluid Usage – total Concentrate Usage
The foam concentrates used had a theoretical expansion ratio of 120:1 to 135:1, whereas,
even without the possible impact of animal convulsions, the actual expansion rates during the
experiment were considerably lower :
Total Fluids Usage Experiment 1
Based on the data provided in the Gurung et al article, the total volume of -water and -foam
concentrate was calculated, using the following formula:
1. Volume (VW) = ((Length x Width x Height)
/ Expansion Rate (ER))
The total Volume Foam Concentrate (VFC) used per barn was calculated, using the following
formula:
2. Volume (VFC) = ((Length x Width x Height)
/ Expansion Rate (ER))x 1%
Results Total Fluid Volume in m3
When applied to the average farm sizes of three typical US poultry barns, the total fluid
volume in m3
is:
.
1 Typical large broiler barn: 2 Newer construction broiler barns : 3 Turkey barn:
Fluid volume A: 21,7 m
3
3
3
Fluid volume B: 24 m3
Fluid volume B: 46,2 m3
Fluid volume B: 98,5 m3
Fluid volume C: 26,4 m3
Concentrate Actual expansion rate
Concentrate A 79,5:1
Concentrate B 76,6:1
Concentrate C 65,2:1

Results Total Foam Concentrate in liters
When applied to the average farm sizes of three typical US poultry barns, the total
concentrate consumption is:
.
Experiment 2, applying CAFs in 30,5 m3 commercial trash dumpster
In Experiment 2, foam was created using a single generator or a single foam nozzle was used
in a commercial trash dumpster with a total volume of 30.5 m3
(the actual length, width, and
height of the container were not mentioned) was filled to a height of 1.2 m - 2.1 m to
determine the expansion rate of the foam. Foam concentrates A and B were used, at 1%
foam concentrate. Expanded foam volume and Expansion Rate ER were calculated from the
recorded data and the actual foam height was used as part of the calculations for resulting
volume and ER.
• Expansion rate for foam concentrate A: 111: 1
• Expansion rate for foam concentrate B: 97:1
Disposal of the discharged foam and wastewater
Even though the concentrates used in these experiments are advertised as being
environmentally friendly, it's essential to be mindful of how the foam solution and
concentrates should be disposed to protect both the environment and those working with
them.
For this reason, the U.S. Environmental Protection Agency (USEPA) National Response Center
demanded that, if more than 38 liters of foam concentrate were released, this had to be
reported. Although reporting is no longer required, many large users of foam still try to use it
sparingly for environmental reasons.
During the experiment, a total volume of water between 21,7 m3
and 108,2 m3
, connected to
that, between 21,7 liter and 108,2 liter of foam concentrate has been applied. The total
volume will increase considerably if the movement of the animals, and the connecting
stratification process connected to convulsions and wing flapping is going to be taken into
account.
1 Typical large broiler barn: 2 Newer construction broiler barns : 3 Turkey barn:
Concentrate A: 21,7 l Concentrate A: 41,6 l Concentrate A: 88,8 l
Concentrate B: 24 l Concentrate B: 46,2 l Concentrate B: 98,5 l
Concentrate C: 26,4 l Concentrate C: 50,8 l Concentrate C: 108,2 l

To ensure safe handling during large-scale depopulation, it's crucial to prevent significant
amounts of foam agent from entering groundwater or surface water. Avoiding direct release
into storm sewers is important because they typically flow into natural water bodies like
rivers, streams, or ponds. Using containment ponds can effectively capture runoff, storing it
until proper processing is feasible.
Another concern arises if concentrated foam or its solution reaches wastewater treatment
facilities. To address this, adding an anti-foaming agent to the disposed foam solution before
it enters the treatment system can help mitigate issues.
Adhering to USEPA guidelines, it's essential to properly collect, treat, and discharge fluids
containing the foam agent to prevent potential environmental impacts on the farm and its
surroundings.

3. Killing Poultry by Inhaling CAF
Using firefighting foams to kill animals carries certain challenges. The main challenge arises
from the fact that firefighting foams are primarily designed to combat fires, not to stun and
kill animals. Applying firefighting foams to animals causes them to experience natural stress
reactions.
Movements of animals move affect the quality of the foam. This movement can burst large
bubbles, causing the compressed air within them to escape, and the liquid gets trapped
between the remaining bubbles. The process of bursting bubbles and forming liquid drops
between them is intensified when animals experience Loss of Posture and Loss of
Consciousness and may start convulsions. To maintain the foam cover around the animals,
the foaming process needs to continue until the animal movements cease.
In the publication titled “Carbon Dioxide and nitrogen Infused Compressed Air Foam for
Depopulation of Caged Laying Hens”,vi
published by Shailesh Gurung et al, in Animals on
January 3, 2018, the authors explored the effectiveness of infusing gases like carbon dioxide
and nitrogen into Compressed Air Foam (CAF), to cause death of poultry by occlusion of the
trachea, caused by inhaling CAF.
The goal of the trials discussed in this publication was to reduce physiological stress of the
operators and to speed up the Cessation of Movement CoM during the occlusion process.
This study had different treatment groups, amongst them were the treatment with CAF filled
with air, CAF filled with nitrogen, and CAF filled with CO2.
Serum corticosterone as stress indicator
Corticosterone CORT is the predominant glucocorticoid released from the adrenal cortex in
animals. Once released into the peripheral circulation, CORT binds to the intracellular
glucocorticoid receptors. Glucose synthesis, lipolysis, and protein degradation are some of
the effects of CORT used by an animal to cope with stressors.
The levels of serum cortisone CORT produced during the trials didn’t differ between CAF
filled with air (8.4 ng/ml), CAF filled with nitrogen (8.0 ng/ml), and CAF filled with CO2 (6.8
ng/ml), (p > 0.05). The infusion of gases into CAF did not cause significant changes in the
CORT concentration of spent hens as compared to the CAF treatment.
Cessation of Movement CoM as indicator of brain death
Animals subjected to euthanasia lose body posture, which is followed by the onset of clonic
and tonic convulsions. The cessation of convulsive movements is an indicator of brain death.
The time it took for movement to cease, known as Cessation of Movement CoM,
differentiated between 180 sec for the CAF filled with air, 167 sec for the CAF filled with CO2
and 132 sec for the CAF filled with nitrogen.

The serotonergic reflexes were similarly high for all groups, indicating a high level of fear and
anxiety before the cessation of movement (COM).
Foam quality parameters
The expansion ratios of CAF filled with air (111:1) and CAF filled with nitrogen (111:1) differ
significantly from CAF filled with CO2 (66:1).
The data suggests that adding CO2 to CAF has a negative impact on the foam quality. This
might be caused by the fact that adding CO2 to the foam leads to the forming of carbonic acid
(H2CO3), which acidifies the water. Acidity lowers the pH of the foam and may contribute to
the breakdown of the foam into opaque foam.
Stratification of the foam and other technical obstacles
The purpose of CAFs (Compressed Air Foam systems) is to effectively manage specific
firefighting emergencies, not to reduce the population of farm animals. This means they don't
consider the specific conditions in the process of euthanizing farm animals. During stunning
and killing, convulsions before, during, and after the Loss of Posture are significant. When is
poultry being killed, intense wing flapping affects the foam, breaking up foam bubbles around
the birds. This creates larger bubbles filled with air, surrounded by collapsed narrower bubbles
mainly holding fluid.
The narrower bubbles, heavier due to more water content, sink to the lower levels of the foam
cloud, while larger bubbles float to the top layer. These larger bubbles are broken easily,
causing the foam cloud to collapse at the surface, requiring more foam and fluid to
compensate for this loss.
This process of heavier, wet foam sinking down can be described as foam stratification.
Within the foam cloud, stratification leads to suffocation of the animals, as they inhale
numerous small bubbles in opaque foam, blocking their trachea and causing death.
Technical challenges also arise from foam properties, impacting various criteria such as foam
concentrates' classification, physical properties like surface tension, spreading coefficient, and
drainage time. Factors influencing foam expansion ingredients, like air, fluid, and gas
temperatures, as well as external conditions like weather seasonal, indoor/outdoor
temperatures and equipment-related factors, also play a role.
When large quantities of CAFs are needed due to animal movements during population
reduction, substantial water usage leads to foam considerable waste. Proper management of
this waste is essential to prevent pollution in sewer systems and soil surrounding agricultural
areas.

Addressing animal welfare issues resulting from foam stratification, combined with technical
challenges due to limited prior knowledge of circumstances, makes predicting success rates
difficult.
In conclusion, foam stratification significantly extends the time needed to euthanize animals
during depopulation efforts. Continuously generating foam to maintain the process water and
concentrate usage. Over time, foam separates into two parts, with the top layer clear and the
bottom layer opaque due to varying liquid content.
Using medium-expansion firefighting foam can euthanize animals but adding gas to medium-
expansion foam doesn't improve results. In all cases, death occurs from inhaling substantial
liquid quantities in opaque foam, blocking the trachea, regardless of if using air or gas to
expand the foam.

4. Killing Pigs by Inhaling nitrogen-filled High Expansion Foam
Introduction: Applying the Livetec technique during the field trials
Since 2007, Livetec Systems in the UK, has been involved in the development of applications
based on using gas-filled high expansion firefighting foam in open top applications. The
technology used is based on submerging animals by and continuous flow of foam,
submerging and enveloping animals inside open top containers, or by covering animals by
rolling on a large blanket of foam over animals in a barn.
Livetec Systems’ technology can be applied in open environments, like inside stables or in non-
concealed open air containers and is based on applying CAF technology. The idea of use CAF-
based solutions for poultry as the basis of the development of new and innovative
depopulation techniques for pigs in stables and open containers looked very promising:
• it could be the CAF-based alternative for CO2 stable gassing and CO2 container gassing
• the use of CAF is widely spread, and the basic technique is therefore available
• it can be applied as a scalable process
• it is cost effective at first sight
• there are sufficient, well-trained, operators available to apply the technique during
emergency situations.
Livetec uses the foaming agent Fomtec LS xMax, produced by Dafo Fomtec AB in Sweden.
Validation of the Livetec Systems Nitrogen Foam Delivery System (NFDS)
On March 31, 2023 the US National Pork Board (NPB) 19validated a study by Todd Williams,
of Pipestone Veterinary Services; Jeff Hill, Livestock Welfare Strategies; Gary Flory, GA Flory
Consulting LLC; Julian Sparrey, Livetec Systems Inc; and Lucia Hunt, Minnesota Department of
Agriculture, based on the use of high expansion nitrogen foam for the large-scale
depopulation of all classes of swine, utilizing Livetec Systems Nitrogen Foam Delivery Systemvii
(NFDS).
This study evaluates the efficacy of high expansion nitrogen foam across different application
techniques, the impact of the extreme seasonal variations of the upper Midwest on the
effectiveness and assesses the impact of the utilization of high expansion nitrogen foam on
the primary mortality disposal methods utilized in upper Midwest in market class pigs.
The high expansion foam produced by the Livetec Systems NFDS surrounds the animal in
large bubbles filled with nitrogen with a base expansion ration of between 300 and 350 to 1,
as mentioned on the information provided by the producer of the firefighting foam.

Loading norm
Animals were supposed to be placed in the containment systems at a density that could go as
high as 120% of the recommended space for transporting, as suggested by the National Pork
Board. To accommodate this density, each 113.4 kg market pig would need 3.2 square
meters of space.
Dimension of the containment
A 30,5 m3
roll-off dumpster, a portable cattle corral gating system (secured by steel posts
at the corners and plywood boardings), and a dug out earthen basin were used for animal
containment (dimensions 6,4 m x 2.1 m x 2.1 m).
Technique and capacity
Livetec Systems uses mobile foam generator units with a theoretically maximum capacity of
50 m3
foam/ min each, assuming that the supplied with gas and foam solution to the correct
pressure and flow rates.
Technical foaming procedure
Once the containment was filled to a height of 2,13 m, the nitrogen system was shut off, and
a 20-minute dwell time was observed to ensure a 7-minute exposure to the nitrogen gas and
ample dewatering of the foam before using air lances (leaf blowers) to remove the foam and
evaluate the animals.
Setting of the NFDS foaming system capacity per volume/hour/minute
The NFDS system was set to create a continuous flow of 7.000 m3
/ hour with two foam
generators. The system mixed gaseous nitrogen with water and Fomtec LS xMax high
expansion foam concentrate, intending to produce bubbles with a 20 mm scope:
• 7.000 m3
/ hour / 60 minutes = 116 m3
per minute
Given the flow capacity per generator is set at 45,3 m3
/min per generator, the total capacity
was sufficient to operate 2 foam generators, setting the flow rate at:
• 45,3 m3
/ min x 2 = 90,6 m3
/ min for two generators.
Water and foam concentrate consumption
The pumping unit and the concentrate mixing units were set to produce 7.000 m3
foam per
hour. With the theoretical expansion rate of 300:1 the fluid consumption was fixed on:
• 23,3 m3
fluid (water-detergent mixture)/ hour
• 23.1 m3
water
• 233 liter detergent / hour (concentration set to 1% detergent/ liter)

Volume capacity to fill the containment with foam
Filling the 30,5 m3 container, with 10 market size pigs (113 kg) would in theory mean:
• 30,5 m3
minus (10 x 0,113m3
) = 29,4 m3
foam; 2,94 m3
per pig
• This foam contains at an expansion rate of 300:1 98 liter fluid, a mixture of 96,9 liter
water and 1,1 liter foam concentrate
Filling time per containment
In order to build up 29,4 m3 foam with 2 active foam generators at full capacity would
theoretically take 19,5 seconds:
• 29,4m3
/ 90,6 m3
/min = 0,325 x 60 sec = 19,5 seconds
Foam production in reality under field circumstances
The actual time to fill the containment during the summer and winter trials differed
substantially. According to the material safety data sheet and the online information
provided by the producer despite that the expansion rate of the Fomtec LS xMax high
expansion foam concentrate was set at > 450:1 @ 6 bar, Livetec mentions the typical
expansion rate of 300:1, leading to a blanket of foam bubbles with a scope of 20 mm of each
bubble. In practice, the foam bubbles during the trials reached an average expansion rate
between 20:1 and 60:1, depending on seasonal influences.

Table: Range of foam properties at continued foaming
Duration of
foaming (s)
Foam premix
used (m3
)
Foam height if
no foam
collapses
(ER=300) (m)
Expansion
rate (ER) if
foam
collapsed but
level remains
at container
height *)
Height of liquid
layer on floor if
foam fully
collapses (ER=1)
(cm)
Theoretical rate**) 20 0,1 2,1 300 0,7
Actual summer min 96 0,5 10,5 60 3,6
Actual summer av 159 0,8 16,8 38 5,8
Actual summer max 240 1,2 25,2 25 8,8
Actual winter min 120 0,6 12,6 30 4,4
Actual winter av 204 1,0 20,8 50 7,2
Actual winter max 296 1,5 31,1 20 10,8
*) assuming all excess gas volatizes and no stratification occurs over the height of the foam column
**) container level filled at set Expansion Rate =300
floor surface (m): 13,44 m
container height (m): 2.1 m
The foaming process needed to be continued until the containment was completely full.
Based on the actual timetables and consumption data described in the final report, the
expansion rate that was reached under practice conditions during the trials was recalculated.
Comments on the observations during the study
The outcome of the trials was observed by a team of experts that provided the impression
that it was impossible to match the theoretical values the setup of the trials. The researchers
concluded that the time to fill the containment took longer in the winter than in the summer.
It appeared (though not measured) that bubble size was smaller during the winter, shrinking
the bubble size when exposed to the winter temperature. For that reason, a construction trash
chute was attached to the end of the foam generator to allow the foam to be better directed
to the container.

5. Opinion of the author
The most favorable method for reducing the population of numerous animals likely involves
utilizing high expansion foam infused with either 100% stunning agents or anoxic gas.
However, implementing this technique in practical scenarios has proven to be quite
challenging. Originating around 2004/2005, the fundamental concept was conceived by the
author, subsequently evolving into diverse applications by Livetec UK, Anoxia BV in Holland,
and HEFT International AB in Sweden.
Significant different technical approaches
The developed techniques can be differentiated in two separated categories: Open system
approach, and enclosed system approach.
The similarities between both methods are that they were discovered at the same time, after
the corporation of the author with dr. Bud Malone at the University of Delaware in 2003.
Both approaches are originated by the idea of using CAFs as the basis to create high
expansion foam; both techniques contain 100% nitrogen; and both techniques were
developed for the purpose of to be applied during large-scale depopulation of poultry.
Still, these approaches cannot be compared because of significant differences:
Open systems:
• Livetec is applying mid- to high expansion CAF firefighting foam, filled with 100%
nitrogen within an open environment with free access to the atmosphere
• Livetec applies its foam technology similar to the techniques that are applied for
firefighting purposes
• Livetec creates a continuous flow of medium to high expansion foam, covering animals
until Cessation of Movement (CoM)
Enclosed systems:
• Anoxia and HEFT developed a different approach, applying specially designed plant-
based high expansion foam, filled with 100% nitrogen
• The foam is created with high speed nozzles that produce large quantities of high
expansion foam with an expansion rate between 1.000:1 and 2.500:1
• This foam is deployed within closed containers, using the foam to replace the oxygen
in the container within 30 seconds to 1 minute depending on the size of the container
(between 0,5 m3
and 40 m3
• Once the container is completely filled with foam, the container is closed, sealed off.
• The foam inside the container is destructed by a strong nitrogen pulse, before Loss of
Posture of the pigs occur

• Destructing the foam ensures that >98% nitrogen is equally distributed within the
container
• Based on the complete absence of foam, the pigs are not able to inhale foam in any
form.
Unfounded claims
Scientific studies since the beginning of high expansion foam development have shown that it
works well in real-life situations without harming animals. Research Institutes of Swedenviii
(RISE) confirmed in 2020 that using high expansion foam filled with nitrogen is a humane way
to stun and euthanize pigs, based on specific animal welfare indicators and measures.
Afterward, RISE conducted more studies exploring this foam filled with nitrogen as a potential
replacement for carbon dioxide in pig slaughter.
RISE tested this technology using enclosed systems developed by HEFT AB. Despite differences
in how the foam is delivered, Sparrey, citing Wallenbeck et al.'s research, suggested that
Livetec's technology, as mentioned in a online publication by Livetec and at the Pork Checkoff
platform, in March 2021, could also be considered a humane method for stunning and
euthanizing pigs.
Vulnerability of high expansion foam
High expansion foam is extremely vulnerable when exposed to negative energy, impacting the
bubble size. The stratification process that causes degrading of the expansion ratio of the high
expansion foam plays critical role in case it will be applied to pigs. Analyzing the data from the
Livetec field trials, the most likely sources of negative energy that need to be taken into when
used open top account are:
• outdoor temperature
• rain
• wind conditions
• movement of the foam over longer distance through a construction trash chute
• movement of the animals
• temperature of the animals
• rough obstacles
This stratification process is not visible for the external observers. Visually, the foam blanket
remains intact, but to remain that status during the entire trial, a continues flow is necessary
to maintain the open top container enclosed with foam.

Main Points in the US Pork Board's Validation Report
Actual processing time
The actual process to create sufficient foam to cover the containment took much longer than
expected, with drastic effects to the actual expansion rate. During the summer trials, the
actual time to fill the containment with foam was between 96 and 240 seconds; 5 to 12 times
longer than anticipated; the actual expansion rate was between 60:1 and 25:1, instead of the
theoretical expansion rate of 300:1.
Actual fluid consumption
The fluid consumption during the foaming procedure was subsequently higher than
anticipated in the pre-calculation: the actual fluid consumption during the summer trials were
in average 784 liter per containment; 78,4 liter per pig; during the winter trials, the fluid
consumption was in average 980 liter per containment; 98 liter per pig.
Actual nitrogen gas consumption
Converting 1.000 liter liquid nitrogen (LIN) creates 682 m3
gaseous nitrogen; to fill one
containment with a net volume of 29,4 m3
containing 10 market size pigs would take
theoretically 100 m3
gaseous nitrogen due to the flushing necessary to reach an oxygen
concentration lower than 2%. This would require 146 liters liquid nitrogen per run:
1000*100/682=146 liter liquid nitrogen per run; 14,6 liter/ pig
The actual nitrogen consumption during the foaming procedure was subsequently higher than
anticipated in the pre-calculation: the actual liquid nitrogen consumption during the summer
trials were in average 186 liter per containment; 18,6 liter per pig; during the winter trials, the
fluid nitrogen consumption was in average 232 liter per containment; 23,2 liter per pig.
Cessation of Movement, Los of Posture, Loss of Consciousness
Even though the Cessation of Movement (CoM) was tracked electronically, the exact
moments when Posture Loss (LoP) and Loss of Consciousness (LoC) occurred couldn't be
recorded accurately.
The data from the accelerometers on the Gulf Coast confirmed the time needed for CoM
during the winter in an earthen basin. During the summer experiments, it was impossible to
collect any data from these sensors due to various reasons. According to the publication, the
main issues were the high humidity in the environment where the sensors were placed, the

sensors getting detached from the leg and wrapping during the foaming process, and
concerns about syncing the sensor times correctly.
Grunts, squeals, and escape attempts
Escape efforts were only documented during the summer assessment at 32 degrees Celsius,
with no audible sounds of distress. The escape attempts varied in duration, spanning from 44
to 66 seconds during the summer assessment. These attempts commenced approximately 20
seconds after the foam filling began in the containment unit.
In contrast, during the winter evaluation at -13 degrees Celsius, not only were escape
attempts observed, but also audible grunts and squeals were noted. Due to the extremely
cold temperatures, data recording devices were unable to function properly during the
winter evaluation, preventing the collection of detailed information.
Animal welfare assessment: Prominent hazards could not be registered
The pigs could only be visually monitored once the foaming process was finished. Even
though the pigs were all deceased after 20 minutes, it was uncertain whether nitrogen was
the definite cause of death. It is questionable whether the expansion rate still was sufficient
enough, causing the pigs inhaling opaque foam when LoP and LoC happened.
Inhaling foam instead of nitrogen
The pigs are at the lower part of the open container, confronted with the smaller foam
bubbles at the lower part of the foam blanket, exposing the pigs at the height of their
head/nose/mouth to opaque foam. This opaque foam causes the occlusion of the trachea, a
significant animal welfare hazard that was especially registered during the winter trials.
It is unknown to what extent occlusion of the trachea contributed to the course of death
because an endoscope for proper intratracheal evaluation was not available during the trials.
Thus, a necropsy was performed to evaluate the amount of foam present in the trachea. The
animal movement and necropsy hindered the ability to state whether the trachea had
obstructed, and it therefore questionable to claim that that the animals died by Anoxia,
caused by the nitrogen.

Water-based CAFs as last resort method for depopulating pigs
Water-based CAFs are considered as the best possible option for depopulation of large
quantities of farm animals, but it is too easy to conclude that the CAF trials carried out by
applying the Livetec approach were successful or not. That depends in the first place on
success was defined before the trials.
Given the absence of large-scale emergency response solutions in the U.S, the definition of
success could be interpreted as method with 100% success in killing animals, within a
reasonable time, causing acceptable level of pain and stress, and against reasonable costs
compared to possible alternative methods.
This is one of the main reasons to argue that applying CAFs for depopulating pigs should be
allowed under constrains, leaving the interpretation of terms reasonable and acceptable to
be determined by either the legislator or the veterinary officer in charge of the depopulation
who then has to decide to use CAFs as acceptable method as a last resort.
Still, there are considerable disadvantaged that need to be addressed, and that will influence
the effectiveness of CAFs.
Conclusion
Although the Livetec report concludes that the results of the study show that using high
expansion foam filled with nitrogen to depopulate market pigs is an efficient and effective
method of depopulation of market swine with acceptable animal welfare, despite the
extremes of seasons in the upper Midwest, the trials failed to produce evidence to support
that assumption.
Analysis of the data presented in the report demonstrates that the expansion rate under field
conditions is insufficient to be classified as high expansion foam. The foam produced during
the field trials resembles Compressed Air Foam as used for depopulating poultry. In both
cases, death is caused by occlusion of the trachea, whereas death by drowning in fluid cannot
be excluded. Adding gas does not have any of the supposed effects. Applying the Livetec
technology makes the foaming process unnecessary complicated, costly, and impractical.
I would like to express my thanks to Dr. Michiel van Mil for all his help and support creating
this report, expressing my personal opinion on the application of high expansion nitrogen
foam for depopulation purposes of pigs.
Harm Kiezebrink MBA
Subject matter expert

References
i
Methods of Mass Depopulation for Poultry Flocks with Highly Infectious Disease, dr. Bud Malone et al, ANECA Symposium
on Emerging Diseases. Queretaro, Mexico, Nov 2007
ii
Proceedings to ANECA Symposium on Emerging Diseases. Queretaro, Mexico Nov 2007.
iii
A Systematic Literature Review on Depopulation Methods for Swine, Arruda et al, published in Animals, at 2020 Nov 2020
iv
Depopulation of caged layer hens with a compressed air foam system, Gurung et al, Animals, January 8, 2018
v
https://www.avma.org/sites/default/files/resources/AVMA-Guidelines-for-the-Depopulation-of-Animals.pdf
vi
Carbon Dioxide and nitrogen Infused Compressed Air Foam for Depopulation of Caged Laying Hens, Shailesh Gurung et al,
Animals January 3, 2018
vii
The Utilization of Livetec Systems’ nitrogen Foam Delivery System for the Rapid, Large-scale Depopulation of Swine, final
report published on March 31, 2023.
viii
Responses of Pigs to Stunning with Nitrogen Filled High-Expansion Foam, by Cecilia Lindahl et al, published in Animals,
November 2020

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