Building upon the work of the “Poison Book Project,” I worked with the University of Washington Libraries to investigate the presence of the toxic pigment "emerald green" (copper acetoarsenite) in Victorian-era bookcloth published between the 1840s and 1860s. After extensively searching UW Libraries collections, 50 volumes were tested by the Pacific Northwest Conservation Science Consortium using x-ray fluorescence spectroscopy; nine were confirmed to contain arsenic. As a result, arsenical books are now labeled, and precautionary measures for the handling and storage of such books have been implemented to mitigate the risk of unintentional arsenic exposure for patrons and library staff.