Arsenic is a highly toxic chemical element that can cause illness or even death if ingested. Synonyms for the word "poison arsenic" include lethal poison, deadly toxin, and harmful substance. Other synonyms for arsenic itself are rat poison, white arsenic, and arsenious acid. Arsenic has been used historically in pesticides, wood preservatives, and even in cosmetics. It is still found in some areas of the world in contaminated drinking water and can be a health concern for those exposed to it over prolonged periods. It is important to handle and dispose of any product containing arsenic with extreme caution.