1. Project 112 and SHAD
Project 112 was a series of chemical and biological warfare tests from the 1960s, many conducted under the sub-program SHAD (Shipboard Hazard and Defense), according to Lee Davidson of Deseret News. These tests exposed military personnel to nerve agents and other dangerous chemicals—often without their knowledge. The goal was to study how these agents would behave under different environmental conditions. Some of the tests even took place on U.S. Navy ships off the coast and in remote areas like Alaska and Hawaii.
The secrecy surrounding Project 112 lasted for decades, even as veterans became sick and sought answers. It wasn’t until the early 2000s that the Department of Defense publicly acknowledged the program. Many veterans were denied medical care for years due to the classified nature of the tests. This case illustrates how long-term consequences can emerge from brief, hidden experiments.
2. The Edgewood Arsenal Tests
From the 1940s through the 1970s, the U.S. Army conducted experiments on over 7,000 soldiers at Edgewood Arsenal in Maryland. Volunteers were given hallucinogens like LSD, BZ (a powerful delirium-inducing agent), and other chemical agents. The tests were meant to evaluate the effects of these substances on combat readiness and psychological stability, according to Genevieve Carlton of All That’s Interesting. While participants technically “consented,” they often weren’t fully informed of the risks.
Many of the test subjects later reported serious psychological issues, including PTSD and long-term neurological problems. The program operated under intense secrecy, and information only began to emerge in the 1970s. Despite the fallout, no one was held accountable for the mistreatment. It’s a sobering reminder of how easily ethics can be compromised in the name of national defense.
3. Operation Sea-Spray
In 1950, the U.S. Navy released a cloud of bacteria over San Francisco to test how a biological weapon might spread in a city, Helen Thompson of Smithsonian Magazine explains. They used Serratia marcescens, believing it was harmless at the time. Unsuspecting residents went about their daily routines, unaware they were part of a military experiment. The test led to at least one known death and several hospitalizations from infections.
This wasn’t an isolated incident—it was part of a series of secret germ warfare tests across the country. The military later admitted to the operation, but not until decades later. The ethical implications of testing on civilians without consent are staggering in hindsight. It’s a chilling example of Cold War paranoia overriding public safety.
4. Operation Drop Kick
In 1956, the U.S. Army released millions of mosquitoes in Savannah, Georgia to test if they could be used as carriers for biological agents. The mosquitoes weren’t infected, but the test was designed to simulate a biological attack scenario. Researchers tracked how quickly the insects spread and how many people they bit. The results helped the military assess how vulnerable American cities might be to such attacks.
Locals were never informed about the release of the insects swarming their neighborhoods. Although the mosquitoes were disease-free, the experiment raised serious questions about public consent. The operation also showed how easily insects could be weaponized. The name “Drop Kick” almost feels too casual for something so unsettling.
5. The Dugway Sheep Incident
In 1968, thousands of sheep died in Skull Valley, Utah—right next to the Dugway Proving Ground, a military testing site for chemical and biological weapons, Lorraine Boissoneault of Smithsonian Magazine explains. The deaths were traced back to a nerve agent called VX that had accidentally drifted from the site during a weapons test. Nearly 6,000 sheep died, and some displayed symptoms eerily similar to human nerve agent exposure. The Army initially denied responsibility, but evidence mounted quickly.
Eventually, the government compensated the affected ranchers, though no one was held liable. The incident highlighted the dangers of open-air chemical testing. Dugway was later the focus of several safety investigations due to mishandled deadly agents. It remains one of the clearest examples of domestic fallout from military testing.
6. The MK-Ultra Subprojects on Military Bases
MK-Ultra is infamous for its mind control experiments, but fewer people know that some of its subprojects occurred on military installations. At least one involved dosing service members with LSD to study its effects on decision-making and memory. The participants often had no idea they were being drugged. This lack of informed consent would later become a central controversy in congressional hearings.
These experiments were driven by fears that foreign powers might use similar techniques. So, the CIA wanted to beat them to the punch—even if it meant compromising ethics. The crossover between intelligence and military testing blurred the lines of accountability. It left many participants struggling with unexplained trauma for decades.
7. Cold War Radiation Tests in Washington State
During the 1940s and ’50s, the U.S. government conducted secret radiation tests around Hanford, Washington—home to one of the country’s major plutonium production sites. Radioactive iodine-131 was deliberately released into the air to study how it would disperse. The experiment exposed thousands of residents downwind, including children. The long-term health effects weren’t studied until much later.
Some residents developed cancers and thyroid problems that were eventually linked to the releases. The government kept the test secret for years, only revealing the details in the 1980s. Lawsuits followed, but many families never received compensation. It’s a haunting case of scientific ambition overriding public welfare.
8. Operation Big Itch
In 1954, the U.S. military tested whether fleas could be used as a vector for biological weapons at Dugway Proving Ground. The fleas were dropped from munitions to study how effectively they could infest a given area. Though not infected with disease, the idea was to replicate a real-world attack scenario. Researchers even measured how many fleas survived the drop and how far they traveled.
The tests were successful in a disturbing way—the fleas spread quickly and latched onto targets. This prompted additional experiments into insect-based biological warfare. Civilians were not part of this particular test, but the implications were clear. The U.S. was actively exploring how to turn nature into a weapon.
9. The Atomic Soldiers and Desert Rock Exercises
Between 1951 and 1962, over 200,000 American soldiers were involved in nuclear testing exercises at sites like the Nevada Test Site. These soldiers, often called “atomic veterans,” were exposed to nuclear blasts with minimal protection. Some were stationed in trenches just miles from the detonation site to study the psychological and physical effects. Others were ordered to walk into the blast area shortly after detonation.
At the time, the military claimed the tests were safe. But many veterans later developed cancers and other radiation-related illnesses. Most were denied VA benefits for years because the records were classified. These exercises are a stark reminder of how far governments will go to study the effects of weapons—even on their own people.
10. Project Chatter
Launched in 1947, Project Chatter was one of the U.S. Navy’s early efforts to explore truth serums and interrogation drugs. Scientists tested substances like mescaline and scopolamine on both animals and humans to find a reliable way to make people talk. Some of the human subjects were military personnel, while others were psychiatric patients. The idea was to create a drug that could help break enemy agents during interrogations.
The project ran into ethical and scientific roadblocks and was eventually folded into larger CIA efforts like MK-Ultra. Its existence only came to light decades later. The early Cold War obsession with mind control led to a murky era of secret experiments. Though it didn’t produce viable results, it paved the way for more dangerous programs.
11. The Green Run
In 1949, a secret experiment known as the Green Run was conducted at the Hanford Site in Washington. The military deliberately released radioactive iodine and xenon into the atmosphere to test Cold War-era detection systems. The goal was to mimic Soviet plutonium production emissions for surveillance calibration. Local residents weren’t warned or evacuated.
It was one of the largest single releases of radioactive iodine in U.S. history. The long-term health effects still aren’t fully known due to poor record-keeping. The operation was only declassified decades later. It’s a prime example of Cold War secrecy endangering public health.
12. The Zinc Cadmium Sulfide Tests
In the 1950s and 60s, the U.S. Army dispersed zinc cadmium sulfide across several American cities to simulate the spread of biological weapons. Cities like St. Louis, Minneapolis, and Corpus Christi were unwitting test sites. The compound, believed to be harmless at the time, was sprayed from planes and rooftops. Researchers then tracked its spread using fluorescent particles.
Concerns have since arisen about its long-term health effects, especially in poor and minority communities where spraying was concentrated. Some residents developed respiratory and other health issues later in life. The government insists it was safe, but many still question the ethics of testing on civilians without consent. The program remained classified until the 1990s.
13. Operation LAC (Large Area Coverage)
This follow-up to earlier aerosol tests involved releasing massive quantities of supposedly “harmless” particles across the Midwest and South. Operation LAC took place in the late 1950s and was designed to simulate how a biological attack might blanket a large region. The Army used aircraft to disperse zinc cadmium sulfide over cities and rural areas alike. Again, residents were never told.
While the government claims the particles were safe, skepticism remains, especially among communities exposed repeatedly. The sheer scale of the operation—covering several states—makes it one of the largest domestic tests ever. It demonstrated how easily vast populations could be exposed to unknown substances. Today, it’s mostly forgotten, buried under layers of Cold War secrecy.
