It's an inferno like in a disaster film - but very real, 100 years ago, in the Palatinate town of Oppau am Rhein. First an explosion, then another. The pressure wave is huge. In Oppau alone, more than 1,000 buildings are destroyed and just as many damaged. The detonations caused window glass to burst in Frankfurt am Main, 70 kilometers away. The bang was so loud that you could still hear it in Munich. In the end, the authorities count more than 500 deaths in the worst chemical accident in German history. Tuesday marks the 100th anniversary of the accident in the Badische Anilin- und Sodafabrik (BASF).

The explosions had occurred in a silo in which 4,500 tons of ammonium sulfate nitrate were stored.

The compound fertilizer developed by BASF had the property of baking together and hardening during storage.

Before loading it was therefore loosened with a safety explosive.

This has been tested beforehand and has already been used 20,000 times, it said.

But on September 21, 1921, a routine blast at 7.32 a.m. caused a catastrophe.

"The misfortune is an urgent warning for us"

At the time of the accident in what is now the Ludwigshafen district of Oppau, the Palatinate belongs to Bavaria. The federal state of Rhineland-Palatinate does not yet exist. The Bavarian state founds the Oppau relief organization, and the population is also very interested. Homeless people need to be cared for. Helpers hand out thousands of pairs of shoes, blankets and coats. For the funeral on September 25, President Friedrich Ebert comes to the left bank of the Rhine, which is occupied by France. The abdicated Kaiser Wilhelm II. Condolences from his exile in the Netherlands.

"The misfortune of that time, but also every other accident that occurs in a BASF plant, is an urgent reminder for us," said BASF CEO Martin Brudermüller on the occasion of the 100th anniversary. “A reminder that in the chemical industry we always have to work with the utmost care. A reminder that we must do everything possible to ensure that such a disaster does not happen again. "

Would such a disaster be impossible for the chemical company today? “The situation at that time is immensely different from the current situation,” says a BASF spokesman. In international agreement, the mixtures of ammonium nitrate and ammonium sulphate as well as other fertilizers containing ammonium nitrate have been classified into safety classes. The ammonium sulphate nitrate produced in Ludwigshafen today belongs to the safest class. "It is granulated and protected from hardening with special anti-caking agents." Even explosives for loosening fertilizers containing ammonium nitrate have long been banned.

With an area of ​​around ten square kilometers, the BASF site in Ludwigshafen is the largest contiguous chemical site in the world.

More than 300 on-site appointments with supervisory authorities take place there every year - including around 160 announced and unannounced inspections, emphasized the BASF spokesman.

"In the past ten years, significantly more has been invested in the Ludwigshafen site than written off every year."

As a result, the company renewed more than a third of the fixed assets at the site, making the plant safer.

"In addition, a total of around ten billion euros was invested in maintenance over the same period and the systems were also adapted to the state of the art in terms of safety."

Despite increased security, the handling of chemicals is not without risk. In the port of the Lebanese capital Beirut, large amounts of ammonium nitrate probably exploded last year. According to official information, more than 190 people were killed. The exact circumstances are unclear. Experts urge you to look at each case individually.