The pigment Emerald Green, also known as Paris Green, offered hue to Van Gogh’s self-portrait, foliage to Monet’s gardens, and a host of god-awful health problems for Impressionist painters alike. Laced with arsenic, the poisonous fumes omitted by this paint wreak havoc on the nervous system and are suspect for causing Monet’s blindness as well as Cézanne’s diabetes. A favourite of Impressionist painters, Paris Green was also used to kill rats in Parisian sewers.