Researchers outlined an elaborate plan in 1949 to use workers at a Tennessee uranium processing plant to learn more about the long-term effects of chronic radiation exposure on humans, a recently declassified document showed. The document suggests that the aim was focused more on using the workers as guinea pigs to learn about radiation health effects than on worker protection, said one investigator. Dr. Harold C. Hodge was quoted in the Oak Ridge memo as describing the need to secure tissue samples from the uranium workers.