WASHINGTON (AP) _ Federal regulators brushed off for nearly two years the ethical qualms that officials at a sister agency had about the experimental use of a blood substitute given without consent to trauma patients, a lawmaker said Monday.

The ongoing study of the Northfield Laboratories Inc. blood substitute Polyheme is unethical, officials from the Office for Human Research Protection told the staff of Sen. Charles Grassley, the Iowa Republican said Monday in a letter to Health and Human Services Secretary Mike Leavitt.

Grassley wrote Leavitt after a Friday meeting between his staff on the Senate Finance Committee and officials from the low-profile federal agency chartered with ensuring the responsible conduct of research involving humans.

Those officials began raising concerns about the Polyheme trial with their colleagues from the Food and Drug Administration in June 2004, according to Grassley. Both the agency and the FDA, which approved the trial, are part of the Health and Human Services Department.

Office for Human Research Protection officials told Grassley's staff that they would never have approved the Polyheme study, Grassley wrote Leavitt.

Friday's meeting came amid public concerns about the safety of the blood substitute following a Feb. 22 report in The Wall Street Journal. The newspaper reported that Northfield has pushed to continue testing the blood substitute without disclosing earlier results, including the deaths of 10 patients from heart attacks.

Northfield Laboratories, based in Evanston, Ill., has said its product did not cause the heart attacks or disproportionately more deaths and that periodic reviews by an independent monitor have deemed the trauma study fit to continue.