Does ‘humane’ slaughter of livestock exist, or is it merely a myth to make us feel better? | Opinion
In veterinary school, we watched American academic Temple Grandin narrate the Glass Walls Videos, produced by the American Meat Institute, which shows how pigs are slaughtered. The film shows pigs going into the gas chamber, and then it cuts to pigs rolling out of the gas chamber — either unconscious or dead.
“After the pigs are anesthetized, they are dumped out,” explains Grandin, a world-renowned and widely respected animal behaviorist who helped design slaughterhouses in ways that focus on animal welfare.
When I saw the 16 hours of footage from inside a Smithfield slaughterhouse in Vernon, California, it showed me the grizzly reality of this so-called humane method of killing. In carbon dioxide gas chambers, pigs suffocate to death by being submerged in high concentrations of carbon dioxide gas. The gas creates carbonic acid, which burns their eyes and mucus membranes. Elevations of carbon dioxide in the blood lead to “air hunger,” triggering fear and panic.
Despite being promoted as a modern, ethical approach to slaughter, it remains uniquely hidden from oversight. The enclosed nature of gas chambers means U.S. Department of Agriculture inspectors are unable to watch as the pigs die inside and therefore unable to determine if the process is in compliance with the Humane Methods of Slaughter Act, which Grandin references in the Glass Walls film.
But Grandin has seen the Smithfield footage, too. Though one of the most prominent voices for improving welfare standards in the meat industry, she faced resistance when she attempted to study gas chambers used by another company. Her proposal to install cameras inside was shut down by the company. Their reasoning? “They didn’t want to look inside the box,” Grandin said.
This refusal begs the question: If these chambers are humane, why the refusal to look inside?
The American Veterinary Medical Association’s Guidelines on Humane Slaughter describe the use of carbon dioxide gas chambers to kill pigs, but when the draft of the guidelines were circulated, veterinarians like myself submitted comments asking for them to recommend the use of cameras inside, our suggestions were ignored.
The association’s guidelines state that “In pigs, vocalization during restraint, handling or painful procedures (squealing) is associated with physiologic measures of stress,” and consider any process resulting in over 5% of the animals vocalizing unacceptable. Anyone who watches the footage will see that far more than 5% of pigs are vocalizing as they descend in the gas chamber’s gondola.
For decades, the animal-based food system has relied on euphemisms like “humane” to maintain consumer confidence. Carbon dioxide gas chambers and other industrialized methods are framed as progress because they facilitate the efficient processing of living animals to consumable protein products. It is in the name of this efficiency that animal suffering is ignored.
We need to look inside the box, and we must consider whether fixing the box is the problem we need to solve. Is building a better gas chamber really what humanity should strive for in 2025?
No amount of oversight can make killing those who want to live “humane.” We must confront the fact that the real solution lies not in reforming slaughter, but in eliminating it altogether.
This story was originally published March 19, 2025 at 5:00 AM with the headline "Does ‘humane’ slaughter of livestock exist, or is it merely a myth to make us feel better? | Opinion."