On this day in 1953, the then-Director of Central Intelligence officially approved project MKUltra.

The project, which continued for more than a decade, was originally intended to make sure the United States government kept up with presumed Soviet advances in mind-control technology. It ballooned in scope and its ultimate result, among other things, was illegal drug testing on thousands of Americans. It wasn’t the first time that the American government “without permission or notice, secretly gathered information on its people,” writes Melissa Blevins for Today I Found Out. But MKUltra has gone down in history as a significant example of government abuse of human rights, and for good reason.

The intent of the project was to study “the use of biological and chemical materials in altering human behavior,” according to the official testimony of CIA director Stansfield Turner in 1977. The project was conducted in extreme secrecy, Turner said, because of ethical and legal questions surrounding the program and the negative public response that the CIA anticipated if MKUltra should become public.

Under MKUltra, the CIA gave itself the authority to research how drugs could: “promote the intoxicating effects of alcohol;” “render the induction of hypnosis easier;” “enhance the ability of individuals to withstand privation, torture and coercion;” produce amnesia, shock and confusion; and much more. Many of these questions were investigated using unwitting test subjects, like drug-addicted prisoners, marginalized sex workers and terminal cancer patients–”people who could not fight back,” in the words of Sidney Gottlieb, the chemist who introduced LSD to the CIA.

“The research and development program, and particularly the covert testing programs, resulted in massive abridgements of the rights of American citizens, sometimes with tragic consequences,” concluded a Senate hearing in 1975-76. “The deaths of two Americans can be attributed to these programs; other participants in the testing programs may still suffer from the residual effects.” While controlled testing of substances like LSD “might be defended,” the committee went on, “the nature of the tests, their scale and the fact that they were continued for years after the danger of surreptitious administration of LSD to unwitting individuals was known, demonstrate a fundamental disregard for the value of human life.”

MKUltra wasn’t one project, as the US Supreme Court wrote in a 1985 decision on a related case. It was 162 different secret projects that were indirectly financed by the CIA, but were “contracted out to various universities, research foundations and similar institutions.” In all, at least 80 institutions and 185 researchers participated, but many didn’t know they were dealing with the CIA.

Many of MKUltra’s records were destroyed in a 1973 purge, and many had been destroyed throughout the program as a matter of course. But 8,000 pages of records–mostly financial documents that were mistakenly not destroyed in 1973–were found in 1977, launching a second round of inquiries into MKUltra.

Although the renewed inquiry resulted in public interest and even two lawsuits, Blevin writes, the 1977 documents “still leave an incomplete record of the program,” and nobody ever answered for MKUltra. Two lawsuits related to the program reached the Supreme Court in the 1980s, she writes, “but both protected the government over citizen’s rights.”