American Samoa's delegate to the U.S. House of Representatives says his hospitalisation earlier this year was due to exposure to the defoliant Agent Orange during the Vietnam War.
Faleomavaega Eni Hunkin was flown to hospital in Honolulu in October last year but the cause of his illness was never disclosed.
He was later transferred to a facility in Washington D.C. for rehabilitation.
Faleomavaega is seeking re-election and there have been questions about his illness.
But he has gone public to reveal he was suffering complications from Agent Orange exposure during his service in Vietnam.
"Like hundreds of thousands of Vietnam veterans I now suffer from the side effects of Agent Orange, including heart and kidney disease, which almost cost me my life. But with proper diagnosis and dialysis treatment my life has been spared."