While clearing out an apartment in Gelsenkirchen, relatives of the deceased owner discovered glass containers with a highly explosive chemical on Friday.
According to the fire brigade, it is picric acid.
Explosives experts from the federal police had determined this.
For security reasons, three apartment buildings in the Resse district were initially cleared.
The substance is in two glass containers, said fire department spokesman Carsten Jost.
They were supposed to be brought out of the house on Friday and driven to a nearby field with the help of a special vehicle.
There the containers are to be blown up in a controlled manner.
Why the substances were in the apartment is still unknown.
Other vessels with as yet unknown substances were discovered in the apartment.
Specialists from the Dortmund fire department should now examine the substances.
"The smallest shock" is enough to cause an explosion
In the case of picric acid, according to the spokesman, "the slightest shock" is enough to trigger an explosion.
The "WAZ" had previously reported on the fire service.
The material used to be used in chemistry classes in schools.
If the acid dries up, it can detonate, for example through heating or a blow.
Therefore, it must always be stored in containers with water - then there is no acute danger.
Icon: The mirror
fek / dpa
