According to the Cologne district government, there were “liquid residues from the production of chemicals for agriculture” in the waste tank farm of the Leverkusen explosion.
The authority announced on Saturday.
The main component of this waste is said to be “chemicals containing phosphorus and sulfur”.
However, the question was still open as to whether the detonation might have released substances that are hazardous to health.
More samples would be taken.
The exact contents of the tanks in the hazardous waste incineration plant had not previously been publicly known.
At a press conference on Friday, the operator Currenta pointed out that it was an object in a preliminary investigation.
The company itself, of course, knows what was in the tanks.
Currenta had stated that this information had been given to the authorities "in full".
The data was sent on Thursday and Friday.
However, emergency services at the immediate site of the explosion would already have had direct information about the substances.
After the massive detonation and a subsequent fire, a huge cloud of smoke rose in Leverkusen on Tuesday morning, and soot particles fell in the region.
In an initial analysis, the State Environment Agency (LANUV) stated that there were no residues of dioxin or dioxin-like substances.
The experts measured only very low values for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs).
The results were seen as the first cautious all-clear.
At the same time, the office announced that it wanted to carry out further analyzes with the knowledge of the exact contents of the tanks.
Until a final clarification, the precautionary measures for residents should be maintained.
This includes, for example, not eating fruit and vegetables from the garden or touching contaminated surfaces.