The devastating finding by the Department of Health and Human Services was prompted by complaints filed after The Post documented cases of children allegedly being used as "guinea pigs" at a Catholic-charity foster home that was affiliated with the hospital.

The federal agency's Office of Human Research Protections concluded Columbia-Presbyterian failed to determine whether it had proper consent and safeguards for the foster kids in AIDS-drug studies.

"When some or all of the subjects (e.g., children) are likely to be vulnerable to coercion or undue influence, additional safeguards have been included in the HHS regulations to protect the rights and welfare of these subjects," the federal agency wrote the hospital.

The hospital's "records demonstrate a failure . . . to obtain sufficient information regarding such safeguards with respect to the enrollment of wards of the state or foster children," the agency concluded in a letter dated May 23.

Columbia-Presbyterian said yesterday it was "in the process of responding" to the letter and could not comment on it.

But it defended the research, which it said was part of a nationwide network of federally sponsored trials.

"These studies, which took place in the 1990s, were instrumental in extending lifesaving HIV treatments to children," spokeswoman Marilyn Castaldi said in an e-mail statement.

"We take seriously our responsibility to protect children — or anyone — who receives care at our medical center."

The Post, following research done by journalist and health advocate Liam Scheff, reported last year that about 50 foster kids were used in 13 experiments with high doses of AIDS medications at Manhattan's Incarnation Children's Center. The tests were conducted by doctors for Columbia-Presbyterian, which was affiliated with the center until 2002.

Some of the studies involved combining six AIDS drugs in "cocktails" for children as young as 3 months.

Jacqueline Hoerger, a pediatric nurse formerly of Incarnation, told The Post at the time, "We were taught that any symptom we saw was HIV-related.

"The vomiting, diarrhea, wasting syndrome, the neurological side effects — they were dying. There was death."

Hoerger later served as foster mother to two HIV-infected sisters from ICC and tried to adopt them.

Hoerger said that when she was allowed to take the girls, 6 and 4, home in 1998, she was horrified to discover they had become "total wrecks" as a result of the drugs.

When she tried to wean the girls off the drugs, foster-care social workers raided her Nyack home and took them away.

In response to last month's letter, Columbia-Presbyterian told the feds that it was "in the process of planning steps specifically to improve protections for children, and particularly foster children."

It said it was increasing the resources to its Institutional Review Boards, which monitor the safety of the hospital's experiments, improving training for researchers, and creating a Web-based system that ensures necessary information for patient safety is collected.

Federal rules require researchers to provide independent advocates to foster children involved in a narrow class of experiments that pose more than a minimal risk and do not hold the likelihood of improved health for the test patients. With Post Wire Services