A prominent human rights group accused the CIA of conducting illegal human experiments and unethical medical research during interrogations of high-profile terrorism suspects under the George W. Bush administration.

Physicians for Human Rights charged Monday that CIA doctors and other medical personnel collected data to study and calibrate the use of waterboarding, sleep deprivation, severe pain and other “enhanced” interrogation techniques, but did so under the guise of trying to protect the detainees’ health.

CIA officials rejected the conclusions of the 30-page report, saying the government did not conduct human experiments on prisoners, which would have violated U.S. and international law.

“The report’s just wrong,” said CIA spokesman Paul Gimigliano. “The CIA did not, as part of its past detention program, conduct human subject research on any detainee or group of detainees. The entire detention effort has been the subject of multiple, comprehensive reviews within our government, including by the Department of Justice.”

The physicians group spent two years evaluating declassified but redacted records about harsh treatment of detainees after the Sept. 11 terrorist attacks and did not obtain additional material. It called for a White House and congressional investigation of its charges.

“The crime of illegal experimentation is equal to the crime of torture,” Nathaniel Raymond, lead author of the report, said in a conference call with reporters.

The CIA confirmed in February 2008 that interrogators had used waterboarding — in which water is poured on a prisoner’s face to simulate drowning — on three suspects in 2002 and 2003. Khalid Shaikh Mohammed, the self-described mastermind of the Sept. 11 attacks, was waterboarded 183 times.

After taking office last year, President Obama banned the practice, which his administration called torture, but he declined calls for a criminal investigation of CIA officers and others who had used the technique.

After the Sept. 11 attacks, Bush administration lawyers approved CIA use of waterboarding, forced nudity, stress positions, extreme temperatures and other so-called enhanced techniques as long as doctors ensured the interrogators did not inflict “severe physical and mental pain.”

The group, based in Cambridge, Mass., said the complicity of doctors, psychologists and other health professionals at those sessions enabled “the routine practice of torture” and helped provide protection against potential criminal liability.

Medical personnel were “required to monitor all waterboarding practices and collect detailed medical information that was used to design, develop and deploy subsequent waterboarding procedures,” the report said.

At one point, the report said, doctors recommended adding salt to the water used in waterboarding. Records show they hoped a saline solution would reduce the risk of pneumonia or hyponatremia, a condition where excessive ingestion of water lowers blood sodium levels. Hyponatremia can lead to coma and death.

Dr. Alan Keller, director of the Bellevue/NYU Program for Survivors of Torture in New York, said the study of waterboarding data “certainly should be considered” unethical medical research on prisoners without their consent. “But it’s also junk science, the notion that it’s safer to drown in the ocean than in the pool.”

CIA doctors analyzed data from 25 detainees who had undergone various enhanced interrogations to determine which technique was most likely to increase the subject’s “susceptibility to severe pain,” the report said.

Health professionals also monitored sleep deprivation of more than a dozen detainees, and then made recommendations on the effect of keeping a prisoner awake for 48 hours to 180 hours.

Dr. Scott Allen, co-director of the Center for Prisoner Health and Human Rights at Brown University, said doctors should have refused to participate in the interrogations for ethical and legal reasons.

“Whether they considered it research or not is irrelevant,” he said.

“All the data points to the fact that these techniques were designed to cause harm, cause pain and cause suffering, so it’s ridiculous to claim you can make them safe,” he added.

bob.drogin@latimes.com