MADISON, Wis. — September 8, 2026 — Animal rights activist and University of Wisconsin–Madison graduate Ryan Blum has released undercover footage recorded inside UW–Madison’s Meat Science and Animal Biologics Discovery Building (MSABD), documenting pigs being lowered into a high-concentration carbon dioxide (CO₂) stunning system prior to slaughter.

Blum says he entered the USDA-inspected slaughter facility during the spring 2026 semester and briefly placed a camera near the CO₂ stunning system. The resulting footage shows pigs displaying pronounced physical reactions as they descend into the chamber, including gasping, struggling and apparent attempts to escape.

The investigation began more than a year earlier. On October 31, 2024, Blum noticed liquid CO₂ tanks connected to the rear of the MSABD while walking across campus. Knowing the building contained UW–Madison’s slaughter facility, he began investigating how the gas was being used.

UW–Madison publicly lists commercial CO₂ stunning among the capabilities of its Meat Science and Animal Biologics Discovery facility. The university describes the nearly $60 million building as a center for meat-industry education, research and outreach and operates a USDA-inspected meat and poultry processing plant within the facility. The newly released footage raises questions about claims that CO₂ stunning provides pigs with a calm or humane transition to unconsciousness.

In a 2024 Meat + Poultry article about UW–Madison’s Harvest & Fabrication School, UW–Madison professor and meat extension specialist Jeff Sindelar described the process as “very calm, very relaxing, very humane.”

Blum’s footage presents a starkly different picture.

“What people don't know, they can’t solve,” Blum said. “This footage gives the public the opportunity to see what happens inside this system and decide for themselves whether this treatment of animals is acceptable.”

Scientific Research Documents Distress Before Unconsciousness

Scientific research supports the behaviors seen in Ryan Blum’s UW–Madison CO₂ gas chamber footage. In a peer-reviewed study, pigs exposed to 80% and 95% CO₂ showed gasping, jumping and retreat attempts before losing consciousness. EEG measurements indicated loss of consciousness occurred approximately 33–47 seconds after descent began.

Researchers characterized high-concentration CO₂ stunning of pigs as aversive, meaning animals can experience distress while still conscious.

CO₂ Stunning at UW–Madison must end

UW–Madison’s Meat Science and Animal Biologics Discovery Building (MSABD) includes a USDA-inspected slaughter facility equipped with commercial CO₂ stunning. The facility is used for meat-industry research, education and training.

The campaign has a clear argument: a major public university should set an example by moving away from systems that treat animals as commodities. Blum rejects the premise that the solution is another supposedly “humane” method of slaughter, pointing to years of undercover investigations documenting animal suffering despite welfare standards and regulatory oversight.

About Ryan Blum and ASAP

UW–Madison graduate Ryan Blum is an animal rights activist and member of Allied Scholars for Animal Protection (ASAP), a nonprofit focused on animal advocacy and education on college campuses.

The full UW–Madison gas chamber investigation and undercover footage are available at the campaign website.

Media Contact
Ryan Blum
Allied Scholars for Animal Protection
ryan@alliedscholars.org