"Assist my people and my land in recovering from the devastation caused by short-sighted and in some cases mean-spirited people who put their own private interests first and ignored the fact that their choices and decisions would result in an inhumane experiment being conducted on an indigenous people," Harrison will tell the committee.
Harrison suffered kidney failure in 1999, only to receive a kidney transplant from his sister.
"You have the power to change things," Harrison told Congress. "You have the power to end this tragic experiment."
"It's been about 25 years since the last mines closed," Harrison concluded. "My people shouldn't have to wait another 25 years for the federal government to accept a responsibility it should have accepted many years ago."
ABC News' Tom Shine contributed to this report.