Arsenic in books: University library blocks tens of thousands of copies. Arsenic compounds could have been used in the production of publications in the 19th century.
The exact number of copies affected by the 60,000 volumes remains uncertain. According to the library, it could be less than ten percent. Potentially contaminated books are already stored safely in Düsseldorf and will be checked if necessary. Between 150 and 200 books in the collections of the universities in Cologne and Bonn could also be affected.