How did killing method condemned for cruelty become standard?

As news emerged over the summer of how Britain’s ‘big four’ supermarkets are sourcing meat from pigs killed using carbon dioxide, outraged consumers have been left with no way of choosing pork, bacon or ham produced more humanely. 

In reply to letters to their chief executives, ASDA, Morrisons, Tesco and Sainsbury’s confirmed that pigs destined for their stores are killed using carbon dioxide. Morrisons said its move from more traditional electrical stunning to the gas killing technique began as recently as the end of 2017.

In addition, farm assurance scheme, Red Tractor, confirmed that CO2 gas killing of pigs “is permitted” within its standards.

“This is just awful; shocking and incredible,” wrote one respondent on Twitter, whilst others reacted with words such as “shameful”, “despicable” and “abhorrent”.

The slaughter method in question involves lowering pigs into a gas chamber containing CO2, causing them to gasp for breath and hyperventilate, causing pain and panic amongst the terrified animals. This often goes on for 30-60 seconds or more.

In 2003, the Government’s own expert advisory body, the Farm Animal Welfare Council (FAWC) condemned the practice, recommending that gas killing of pigs with high concentrations of CO2 should be banned within five years.

Sadly, that recommendation was never acted upon.

Now, at least half of Britain’s pigs are killed this way.

Instead of being discarded as some terrible anachronism, CO2 stunning has instead become industry standard. The convenient way of killing pigs. Yet, it’s not only major supermarkets and industry assurance schemes like Red Tractor that are allowing it: even some organic pigs can be killed this way.

So where does this leave consumers?

Well…, powerless. Except to avoid pig-meat altogether.

As it stands, consumers have no way of knowing whether meat comes from pigs gassed or stunned by any other method. There’s nothing on the label. There’s no obvious way of choosing one supermarket over another, in this case, as most if not all have gone down this route. You can’t even tell by choosing higher welfare labels like ‘outdoor bred’, ‘outdoor reared’ or ‘organic’. Consumers are left with the very real assumption that if you’re buying pork or bacon, then it may well be from an animal killed in a gas chamber.

How can it be considered humane?

The widely accepted understanding of humane slaughter involves a stunning or killing method that is instant or non-aversive. According to the Humane Slaughter Association (HSA), a charity set up more than a hundred years ago to promote humane killing methods, “If a stunning method does not cause instantaneous insensibility [until dead], the stunning must be non-aversive (i.e. must not cause fear, pain or other unpleasant feelings) to the animal.”

Against this common-sense benchmark, gassing pigs with high concentrations of CO2 falls well short of the mark.

As far back as 1996, clear scientific evidence highlighted that CO2 stunning for pigs causes severe welfare problems and a high degree of suffering. The study concluded that pigs show profound aversion to the gas which leads to “severe respiratory distress”. More recent evidence suggests that the pigs take 30-60 seconds or more to lose consciousness. That’s an awful long time when terrified and fighting for breath.

This science was reviewed in 2003 by FAWC, the UK Government’s own expert advisory body on welfare, which concluded that CO2 pig slaughter was “not acceptable” and called for a ban within five years.

A year later (2004), the European Food Safety Authority (EFSA) also condemned CO2 stunning for pigs as being “aversive” to the animals.

In 2009, the newly adopted EU Regulation on slaughter and welfare expressed disquiet, stressing the importance of exploring a phase-out of CO2 for pigs.

In 2015, leading animal welfare organisations, including Compassion in World Farming and Eurogroup for Animals, wrote a well-publicised letter to the European Commission demanding a ban on the method described as being “aversive” and causing “pain and suffering”.

Why condemned then adopted?

So how did a slaughter method so widely condemned as cruel become the norm?

In short, there seems to have been a quiet campaign to erode confidence in the slower, perhaps more labour-intensive method of electrical stunning. Yes, electrical stunning – where pigs are rendered unconscious by having electrical tongs applied to their head or body – has its own problems. However, when done well, it can render a pig unconscious within a fraction of a second: well before a mammal’s nervous system can register pain. In welfare terms, the stun is instant. 

However, lack of investment in training, design and equipment has meant that all too often the method isn’t done well.

The drawbacks of electrical stunning have slowly but surely been used to prepare the ground for the mass uptake of CO2.

Perceived positives of CO2 gas killing have been played up; such as the ability to keep pigs in groups all the way to those final moments. Pigs are social animals, becoming anxious and stressed when separated so keeping them together is seen as better handling. However, it is hard to see how this balances against the severity of suffering during the killing process. 

Donald Broom, Professor of Animal Welfare at Cambridge University, told the Mail Online, ‘The handling systems associated with gas stunning are generally better for pig welfare than those when electrical stunning is used.’

But he added: ‘When carbon dioxide stunning is used, the welfare of the pigs is poor until they lose consciousness, usually about 30 seconds. They gasp, throw their heads around and squeal.’ 

If killing with high concentrations of carbon dioxide is the answer, surely we’ve got the question badly wrong?

My view is that the move was driven by asking the wrong questions about animal welfare as well as the attraction for industry of efficiency and scale.

Larger slaughter plants in the UK and Europe, as well as Australia and South Africa, are now using CO2 stunning for pigs. According to the HSA, abattoirs that kill a lot of pigs in a short time (800 pigs per hour or more) see gas-stunning as often the “most reliable slaughter method”.

The UK’s National Pig Association (NPA) confirms the tendency for carbon dioxide to be the method of choice by larger abattoirs with high throughputs of animals. Indeed, “best available practice” is how the NPA’s June 2018 briefing describes it. The same briefing goes on to state how it is well documented that pigs “find high concentrations of carbon dioxide aversive and will try to avoid exposure to these.”

These two statements taken together add up to the conclusion that, on a large commercial scale, there is currently no humane way to kill a pig.

It seems the widespread adoption of CO2 stunning is part of the wider roll-out of mass automated pigmeat production. It is an evolution of an industrial farming practice that seems to value throughput over welfare and animal sentience.

International concern

Concern about the adoption of this widely criticised slaughter method is not confined to Britain.

I asked Bo Algers, Professor Emeritus at the Swedish University of Agricultural Sciences, Uppsala and now a spokesperson for Compassion in Sweden, for his view on why CO2 has become the method of choice?

“Probably because it is a cheap way to produce pork. It is a cheap and convenient way in a type of production which is based on a [high] flow of animals through a meat processing system. It’s cheap because CO2 is not very costly and it allows for a high speed of animals through the system.”

This analysis seems to be borne out by a UK Food Standards Agency report which found that 7 slaughterhouses using CO2 were processing more pigs during the same time as 120 plants using the more labour-intensive electrical stunning method.

Algers’ own research into CO2 stunning has led him to call for the practice to be banned. He told me how pigs arrive at the slaughterhouse already stressed from the journey from being “in a completely new environment, with new pigs, new sights and sounds. It is a sensory overload,” he said.

“We should abandon the use of carbon dioxide for both mammals and fish due to the negative affects including pain and anxiety,” he concluded.

Recent media interest, sparked by a fluke CO2 shortage, threatening fizzy drink supplies and coinciding with the festivities surrounding the World Cup, seem to have precipitated signs of a rethink.

The British Retail Consortium (BRC), which represents the supermarket industry, issued a statement saying, “Retailers take the welfare of animals extremely seriously. Co2 stunning is a legally permitted form of slaughter…. Research is underway to look at alternative stunning mixes although it may be some time until these are validated, approved and suitable for large-scale use.”

The UK government has allocated £400,000 of research funding to develop more humane alternatives to high concentration CO2 stunning.

A Defra spokesperson said, “We are aware of concerns over the use of carbon dioxide to stun pigs and are funding research alongside the Humane Slaughter Association to look into alternatives to the practice.”

Leading scientists believe that alternative electric stunning systems or using different gasses may hold the key to more humane alternatives. The use of argon as a non-aversive gas alternative is being investigated along with Low Atmosphere Pressure Stunning (LAPS). LAPS stuns animals by gradually reducing atmospheric pressure and hence the amount of oxygen available for animals to breathe. It mimics the reduction in pressure experienced by military pilots flying at high altitude and is not known to be unpleasant.

Call for Action

With the search for alternatives picking up pace in the wake of publicity, Compassion and the RSPCA have issued a joint statement, calling for “the use of high concentrations of carbon dioxide for the killing of pigs to be legally prohibited; and new, humane systems to be developed and commercially available to replace the use of high concentrations of carbon dioxide” by no later than 1^st January 2024.

Clearly, action is needed and the sooner the better.

This summer’s freak carbon dioxide shortage has drawn attention to how bringing home the bacon has never been so cruel. It is up to those who care to ensure that this version of hell masquerading as ‘humane’ slaughter is seen for what it is and outlawed swiftly. 

Please click here to take action by writing to Michael Gove, Defra Secretary of State, calling for urgent action to ban high-concentrate carbon dioxide stunning. Thank you.

Philip Lymbery

7^th August 2018