Yale Study: Cancer Rates Between 4% And 8% Higher In CA/IA/TX Counties Where People Live Near CAFOs

People living near concentrated animal feeding operations, or CAFOs, in California, Texas and Iowa suffer from higher rates of cancer, suggesting that the air and water pollution from the massive farms may be playing a role, according to a new study. The study, published in the journal Environmental Research, comes just weeks after a years-long report in Iowa found the state’s agricultural chemicals and CAFO pollution are, in part, behind its rising cancer rate.

In the new study, Yale University researchers examined the rates of all cancers over the past 20 years in Texas, California and Iowa counties along with the density of CAFOs in the counties. High exposure counties were defined as those in the top 25% of CAFO density for their state.

The researchers found rates for all types of cancers were 4% higher in highly exposed California counties, and 8% higher in highly exposed Iowa and Texas counties when compared to counties with lower CAFO density. They found certain cancers were more strongly associated with CAFO density in each state. For example, stronger links were seen for bladder cancer in California, colorectal cancer in Iowa, and lung and bronchus cancer in Texas. Iowa has the highest number of CAFOs in the country, according to federal data that ranks California fifth and Texas sixth.

Lead author Jiyoung Son, an associate research scientist at the Yale School of the Environment, said there are “multiple pathways” by which CAFOs could cause higher cancer rates. They emit air pollutants including ammonia and hydrogen sulfide, particulate matter, and volatile organic compounds, she said, which can form secondary pollutants in the atmosphere.

EDIT

https://www.thenewlede.org/2026/04/cafos-cancer-pollution/