Production occurred on the “Flat” of the Refugio Valley, in rough buildings of wood and metal, each housing a stage of production from the liquid acids to boxes of finished dynamite. For safety, buildings were set in small clusters or spaced apart; many were sunken behind embankments to direct the force of explosions upwards. Rows of tall eucalyptus trees were planted around the valley to further buffer explosions.
Batches of the dangerous chemicals were moved from one “house” to the next over a network of pipelines, roads, elevated wooden boardwalks and narrow-gauge railroad lines.Men carefully wheeled five hundred pound batches of nitroglycerine in “angel buggies” over the boardwalks. Locomotives powered by compressed air shuttled freight cars up the valley, dipping through a tunnel beneath State Highway 40.
European settlement of Refugio Valley first, briefly, was for agriculture. From 1878 the main production facilities of California Powder Works occupied the lower Refugio Valley; to the southeast in the upper Valley were small storage and shipping facilities.
When the era of explosives manufacture ended, the upper Valley was subdivided and sold as residential lots beginning in 1972.
Later, beginning in 2001, residential development occured in the lower Refugio Valley as economic values and new construction techniques overcame geologic and hydrologic challenges.
