This paper describes the structures, operations, and history of the Research and Production Plant, Parkgate, a munitions facility developed by the Irish State in the early years of World War II (referred to in Ireland as 'the Emergency'). Located on the edge of the city of Dublin and within the historic curtilage of Phoenix Park, its emissions were the cause of some controversy and resulted in a local health scare, suppressed and censored by the Fianna Fáil government of the day. The Plant's eventual closure was brought about by complaints from the Office of Public Works regarding severe chemical damage in the adjacent Peoples' Garden and to trees and other vegetation further away in the Park proper. In the meantime, production had switched to service a private concern, which was to benefit further from the arrangement before restrictions on the importation of phosphorus and other chemicals were lifted in 1946. The structures were identified and recorded over the summer of 2007 and the research conducted the following winter, based on files held in the Military Archives and contemporary parliamentary reports.