This declassified video shows the US government testing biological warfare -- on the US

From 1949 to 1969, the US government carried out at least 239 tests on unsuspecting US civilians that were meant to simulate biological weapon attacks.

Officials back then used what they believed were harmless “simulants” of actual bioweapons. But Leonard Cole, the author of the investigative book “Clouds of Secrecy: The Army’s Germ Warfare Tests Over Populated Areas,” which documented the tests, tells Tech Insider that these supposedly harmless germs are “all considered pathogens now.”

A newly declassified 1952 Department of Defence film, released on Sept. 30, 2015 in response to a FOIA request by the site Government Attic, shows the enthusiasm with which the DoD viewed those tests at the time.

Both in tone and content, it’s hard to believe, especially from the non-Cold War perspective of today.

Government Attic posted a copy of the video on October 12, and Tech Insider verified its authenticity by comparing it to a version provided by an official at the US National Archives.

We’ve broken the film down into GIFs for easy viewing (pardon the quality), but the full version, which we’ve uploaded to YouTube, is at the end of the post.

The film details the US capabilities for using biological weapons at the time, and the ways testing in inhabited areas helped them develop these strategies.

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Most of the film is dedicated to the 'offensive' capabilities gained by these experiments.

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Such attacks are meant to devastate food supplies and incapacitate both armed forces and 'the human population that directly supports them.'

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The narrator says the Navy can deliver a biological or chemical attack 'anywhere on that three-quarters of the Earth's surface that's covered by water' -- and hundreds of miles inland.

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One of the first major experiments tested a biological attack on San Francisco.

Similar tests were carried out by the USS Tercel off the Southeast coast in the Atlantic, where flat lands and weather made dispersal 'favourable.'

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This showed just how effective a real biological attack would be: 20,000 square miles received the particles, according to the film.

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Submarines also dropped mines full of simulants off the coast of Key West to test that attack method as well.

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The film notes that the sprays are are actually invisible, unlike in this animated scene.

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Submarines dropped the mines before scooting off.

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Then they rose to the surface, releasing particles, which 'demonstrated that the Navy has a powerful offensive weapon for biological warfare.'

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They tested dropping similar mines from the air and showed that scuba divers could drag them in as well.

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That wasn't all. The military devised ways to shoot biological and chemical weapons from ships and marines on land.

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It also developed weapons that planes could release directly -- then tested them all over the US, later dropping zinc cadmium sulfide from the border of Canada down to St. Louis.

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Defensive procedures are described in the video, too. They include protective clothing, immunization, and built-in sprays to wash chemical and biological particulates from a ship.

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Much of this information first came to light in the 1970s. Cole and others revealed more in later investigations.

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But as this film shows, there's much that still hasn't been declassified. This document just captures what was known a few years from the start of these experiments.

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It's taken decades of work to get the information we have so far about US biological warfare testing. We'll see what continued pressure can reveal going forward.

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