Improper payments to dead retirees increased 70 percent in the past five years, far higher than the 19 percent climb in overall annuity payments, the report said.

The payments are on the rise because OPM is doing a poor job of tracking potential cheats, McFarland said. In one case, a deceased annuitant’s son continued receiving federal benefits until 2008 — 37 years after his father’s death. OPM learned about the improper payments — which exceeded $515,000 — only after the son died. The agency never recovered the money.

An OPM spokesman said Thursday that the agency is reviewing the report and had no immediate comment.