During the late nineteenth and early twentieth centuries, arsenic was used as an embalming agent in the United States. In 1996, Konefes and McGee brought the potential danger of arsenic poisoning during excavation to the attention of archaeologists. They developed methodology that was later refined by the present authors. This article discusses the history of arsenic as an embalming agent, explores socioeconomic and demographic factors that might suggest the presence of arsenic in certain burials, and presents methods for testing arsenic in archaeological contexts. We also discuss environmental impact mitigation considerations and review examples of arsenic testing in archaeological contexts.