25% of adult and subadult California sea lions have cancer. University of California marine scientist David Valentine may have discovered a cause.

Working with little more than rumors, a hunch, and a robotic submersible, Valentine discovered what had been hidden since the 1940s: countless barrels of toxic waste, laced with DDT, 3,000 feet below the ocean’s surface littering the ocean floor between Long Beach and Catalina Island. 

Read article and watch CBS news video here:

https://www.cbsnews.com/news/california-ddt-environmental-disastersea-lions/