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CO₂ Stunning in Pigs Awareness

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Understanding the Practice

In modern commercial slaughter systems, most pigs are stunned before slaughter.

One of the most widely used methods globally — including in Australia — is carbon dioxide (CO₂) gas stunning.

This process involves:

  • placing pigs into a chamber or gondola

  • lowering them into high concentrations of CO₂ gas (typically 70–90%)

  • rendering them unconscious before slaughter

This method is commonly used because it allows pigs to be handled in groups and supports large-scale processing.

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Why This Practice Is Being Questioned

While CO₂ stunning is widely used, it has become a significant focus of animal welfare concern and advocacy.

Research and welfare bodies have identified that:

  • CO₂ gas is highly aversive to pigs

  • it can cause:

    • breathlessness

    • irritation to eyes and airways

    • distress behaviours such as gasping and attempts to escape

  • pigs may remain conscious for a period before losing awareness

Scientific and policy reviews have concluded that this method can cause avoidable pain and distress prior to unconsciousness

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Current Industry Position

Despite concerns, CO₂ stunning remains widely used because:

  • it is efficient for large-scale operations

  • alternatives are still being researched and are not yet widely implemented

  • regulatory systems currently allow its use

In Australia, it is estimated that the majority of pigs are stunned using CO₂

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What Is Being Advocated For

Animal welfare organisations and researchers are calling for:

  • phasing out CO₂ stunning

  • development of more humane alternatives, such as:

    • inert gases (argon, nitrogen)

    • improved electrical stunning systems

  • improved monitoring (e.g. CCTV in slaughter facilities)

  • stronger regulatory oversight

In 2025, a government advisory body recommended that the industry move toward replacing CO₂ with more humane methods within a defined timeframe

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Current Campaigns & Petitions

 Global Campaign

End CO₂ Pig Slaughter (Active Campaign)
Run by Compassion in World Farming

  • Calls for governments to phase out CO₂ stunning

  • Encourages public support for humane alternatives

  • Based on findings that pigs can remain conscious for up to 60 seconds while distressed

 Visit: https://action.ciwf.org.uk/page/95747/action/1

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 Australia Campaign Awareness

Ban Gas Chambers for Pigs
Run by Farm Transparency Project

  • Highlights use of CO₂ gas chambers in Australian facilities

  • Advocacy focus:

    • banning gas stunning

    • increasing transparency

    • regulatory reform

 Visit: https://www.farmtransparency.org/campaigns/gas-chambers

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 Australia Petition

Pigs Without Borders Campaign
Run by Animal Liberation

  • Calls for:

    • stronger animal welfare protections

    • review of intensive pig farming practices

    • improved regulation and transparency

 Visit: https://www.al.org.au/pigs-without-borders/petition

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 Recent Petition Activity (Status Update)

  • Over 22,000+ signatures were submitted to government calling for a phase-out of CO₂ stunning 

  • Government advisory bodies have acknowledged welfare concerns

  • Policy discussions and consultations are ongoing (as of 2025)

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Organisations & Further Information

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A Balanced Perspective

It is important to recognise:

  • Stunning is used to reduce suffering compared to unstunned slaughter

  • CO₂ remains widely used due to practicality and scale

  • There is growing global agreement that improvements are needed

This is an evolving area, with ongoing research, industry change, and public discussion.

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Why This Awareness Matters

This topic is often highlighted because:

  • it occurs on a large global scale

  • the welfare concerns occur prior to unconsciousness

  • there is increasing recognition that more humane alternatives may be possible

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This page is offered as a space for awareness.

If this topic resonates with you, you may wish to explore the resources and initiatives above.

If it does not, that is completely okay.

Awareness is not about judgement — but about understanding the systems we are part of, and choosing how we respond, if at all.

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