UW–MADISON. GAS CHAMBERS.
I'm Ryan Blum. I snuck into the University of Wisconsin-Madison's Meat Science and Animal Biologics Discovery Building’s (MSABD) USDA slaughterhouse. Inside, I filmed pigs being lowered into a CO₂ gas chamber—and exposed the cruelty happening behind closed doors.
See the Evidence Yourself
Pigs gasp, scream, and struggle to escape as they are exposed to high concentrations of CO₂ in UW–Madison’s gas chamber.
UW-Madison Professors claim it's a:
Does this look humane?
UW–Madison claims to be the only University in the United States to operate a CO₂ stunner for pigs.
My story
THE INVESTIGATION
How it all started: On October 31, 2024, while walking on campus, I noticed liquid CO₂ tanks connected to the back of UW–Madison’s Meat Science & Animal Biologics Discovery Building (MSABD). I knew the building contained the university’s slaughter facility, and the tanks led me to investigate whether CO₂ was being used on animals inside. The University’s website confirmed that.
What began as that observation eventually became an investigation that I worked to develop a plan for more than a year.
During the spring 2026 semester, I entered the slaughterhouse inside the MSABD and managed to briefly plant a camera to record pigs inside its CO₂ stunning system. The hardest part: I did it alone.
WHAT IS CO₂ STUNNING?
High concentrations of CO₂ do not make pigs immediately unconscious. As CO₂ rapidly accumulates in the body, pigs experience respiratory difficulty and an intense drive to breathe before losing consciousness. Scientific studies have documented pigs gasping, attempting to retreat or escape, jumping, and experiencing muscular contractions while they are still conscious. (PubMed)
CO₂ exposure can also irritate the mucous membranes and causes hyperventilation; scientific reviews characterize high-concentration CO₂ stunning as aversive. Research measuring brain activity has found that pigs can remain responsive for a period after entering high concentrations of CO₂, meaning the distress occurs before unconsciousness. (PubMed)
Other Gas Chamber Footage
CALIFORNIA
Raven Deerbrook and Direct Action Everywhere (DxE) investigation footage.
THE NEW YORK TIMES
FEBRUARY 4, 2023
UNITED KINGDOM
Joey Carbstrong’s Pignorant undercover footage from a UK abattoir.
THE GUARDIAN
MAY 2, 2023
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ABOUT ME
ANIMAL RIGHTS ACTIVIST
I am an animal rights activist whose primary focus is education: what people don't know, they can’t solve. My work in the movement has included street outreach, presentations, undercover investigations, animal rescues, protests, and writing. I have also interned in both the U.S. Senate and U.S. House of Representatives.
At UW–Madison, I studied science communication, food systems, global health, and political science. Since graduating, I have joined Allied Scholars for Animal Protection (ASAP), where I focus on making animal rights impossible to ignore on college campuses.