The Poison Book Project: Rare poisonous book discovered in Leeds library over 150 years after publication

Leeds Central Library’s copy of My Own Garden: The Young Gardener’s Yearbook was published back in 1855, and has been safely tucked away behind the scenes at Leeds Central Library, well away from visitors.

Recent research carried out by experts at the library revealed that the seemingly unassuming book most likely owes its vivid, emerald green colour to a dye containing quantities of arsenic, which can be lethal when ingested.

The startling discovery came to light when senior librarian Rhian Isaac began cross-referencing the library’s vast collection against the database of The Poison Book Project. She found the exact edition of the book housed in Leeds featured on the list of books which are known to have been coloured using arsenic.

Rhian said: “As a librarian, it’s always incredibly exciting to discover any sort of rare, or unusual book in our collection. But this project is also really important as it helps librarians across the world work together and understand how and when these books were made as well as what steps we can take to keep track of them and make sure they are safely stored and cared for.

“Amazingly, heavy metals were once quite commonly used in the production of books as a way to achieve what was considered a very aesthetically pleasing shade of green. Whilst people at the time were certainly aware substances like arsenic were harmful, they probably didn’t understand the many different ways they could be accidentally ingested."

The book will now be secured and safely stored before being sent away and scanned with a specialist spectrograph which will determine exactly how much arsenic it contains.

Councillor Mary Harland, Leeds City Council executive member for communities, said: “Our libraries are a fantastic public resource, but they also play a pivotal role in the preservation our city’s rich and fascinating heritage.

“The incredible work that goes on behind the scenes to catalogue and document our unique collection plays a huge part in that and ensures these captivating stories are not lost to the ages.”