Explosives Manufacture at the Hercules Works
The California Powder Works purchased a 44.94-acre portion of Rancho El Pinole from the Martinez heirs in 1879. Subsequent purchases increased the site to about 3,000 acres, extending two miles up Refugio Valley.
By 1881 the first acid plants were feeding nitroglycerine production lines. In less than twenty years, under the direction of Captain William Russell Quinan, the Hercules plant would become the largest in the world, producing more than half the dynamite made on the West Coast.