German authorities destroyed a cache of chemicals discovered in a homeless shelter that could have been used to make hazardous materials, police said on Tuesday.
Police said there was no reason to suspect a terrorist link, but noted that the materials could have been used to make bombs.
More details about the products or their origin remain unclear.
Some of the chemicals could not be transported safely and had to be destroyed on site during the night.
That required about 100 people being evacuated from nearby homes.
They were able to return early Tuesday.
Three men and a woman were arrested after the find and charged with possession of dangerous substances.