UK Meat Industry Told To Phase Out CO2 'Stunning' For Pigs Within Five Years

A landmark report by the independent Animal Welfare Committee (AWC) has called for widespread CO2 “stunning” of farmed pigs to be phased out in the UK.

It confirmed that exposure to CO2 is an ongoing welfare issue that causes animals avoidable pain and fear before their deaths. The report called for an end to the practice within at least five years, though specified that the industry should seek to update its practices “as soon as possible” and work on alternatives.

The AWC’s report confirms what animal rights charities, scientists, and investigators have maintained for decades: that there is “significant” evidence exposing pigs to CO2 causes “avoidable” pain, respiratory distress, and fear before death.

The report found behavioral evidence for pigs’ pain and fear, including “vocalizations, hyperventilation, and escape attempts,” all of which were documented while the animals were still fully conscious. The process takes around 90 seconds.

Titled “Opinion on the welfare impacts on pigs of high concentration CO2 gas stunning and of potential alternative stunning methods,” the new report examined existing evidence and made several key recommendations to the meat industry.

In addition to suggesting CO2 be phased out, it also encouraged improvements to animal welfare overall by minimizing “physical coercion,” slowing slaughter volume and speed, utilizing new technologies, and requiring more training and qualifications.

Meat suppliers would ‘vigorously oppose’ a move away from CO2

The suggestions have met pushback from some parts of the pig farming industry. The Association of Independent Meat Suppliers (AIMS) said it would “vigorously oppose” a move away from CO2 stunning, as reported by The Scottish Farmer.

AIMS suggested that pigs are currently “handled calmly in small groups” and lose consciousness “rapidly and without restraint,” all while being monitored “continuously by trained staff and vets.” This image is contradicted by the more than 20 years of evidence examined by the AWC, first-hand accounts, and undercover films.

Most UK pigs are now stunned using CO2 gas

Photo shows an abandoned slaughterhouse/meat-packing plant — Adobe Stock More than 10 million pigs are slaughtered each year in the UK

Most of the pigs killed in the UK meat industry are stunned with high-concentration CO2 before slaughter. According to Compassion in World Farming (CIWF), uptake of CO2 stunning increased from 52 percent in 2013 to 88 percent in 2024, and to 90 percent in 2025. The other 10 percent of farmed pigs are stunned with either electricity or the euphemistically named “percusive method,” a “severe” blow.

National Pig Association (NPA) chief executive Lizzie Wilson acknowledged the need for welfare improvements and told Farming UK that “there is still no conclusive ‘best’ alternative,” citing the limitations of cost, meat quality, and the capacity of facilities. Many animal advocates believe there is no such thing as the ethical slaughter of animals, but organizations such as CIWF simultaneously advocate for minimizing pain and distress as much as possible within the meat industry.

CO2 stunning is popular because it is cheap and simple for the industry. However, the new report noted specifically that “the use of an aversive or painful method to allow for greater throughput or cost-cutting is not justifiable” due to the risk of harm.

More than 20 years ago, the Farm Animal Welfare Council – another government advisory body – said CO2 stunning “is not acceptable and we wish to see it phased out in five years,” and called for 2007 as a hard deadline to end CO2 gas use.