Germany also manufactured large amounts of chemical weapons for World War II. The population was prepared for a gas war. Mustard gas—sometimes called ‘Deadly Lost’ in German—had already been used in the First World War. The dangerous agent played an important rôle in the second as well.

‘After the [Fascists] came to power, they began with [further] rearmament. One aspect of that was making warfare agents for Germany. They built factories to manufacture the toxins, which then had to be filled into munitions. In total, there were seven munition‐filling centres built that worked with mustard gas.’

German chemists were behind some of the most gruesome discoveries in modern warfare. A 1938 propaganda film showcased the power of the nerve agents tabun and sarin:

‘After just a few seconds, the motor neural stem cells are paralysed, and breathing ceases. Severe asphyxiation cramps follow. Breathing is stopped while a heartbeat can still be detected.’

In the end, even the [Third Reich] backed away from using these weapons of horror.

There is also a theme that recurs throughout this documentary:

The costs are an obstacle. Germany’s most toxic hole, Dethlinger Pond in Lower Saxony, could easily become the world’s most costly one. The clean up comes with an estimated €15,000,000 price tag.

[…]

Now the authorities say it’s up to the new owners to clean up any old ordnance. But the investor doesn’t want to pay for it, because that would mean passing on the cost of his toxic legacy to buyers and tenants.

[…]

Other studies have shown that public areas are also contaminated with arsenic, an uncomfortable truth for the City of Berlin. After decades of [ignoring it], authorities have to face up to this toxic wartime legacy, and it’s likely to cost them a lot.

(ETA: orthography.)