California Powder Works
California Powder Works was the first explosive powder manufacturing company west of the Rockies. When the outbreak of the Civil War cut off supplies of gunpowder to California's mining and road-building industries, a local manufacturer was needed. Originally located near Santa Cruz, California, the company was incorporated in 1861 and began manufacturing gunpowder in May 1864. For fifty years, it was a major employer in the county, employing between 150 and 275 men. The powder works was located on a flat adjacent to the San Lorenzo River, three miles upstream of Santa Cruz.
Facilities at Santa Cruz 
A dam was built on the San Lorenzo River upstream of the powder works on what is now Henry Cowell Redwoods State Park. A 4-foot by 6-foot tunnel 1200 feet long was dug in 1863 to bring water from the dam through the powder works. Water powered powder mill machinery and was used to dissolve and purify the crude potassium nitrate from Chile. Water was distributed through the powder works by a system of flumes later dismantled when electricity became available to power the wheel mills. Charcoal was manufactured locally using redwood fuel to char willow, madrone and alder. To facilitate transport and shipping, the company built a covered bridge across the river, still in use today, and a wharf off the main Santa Cruz beach. The wharf was used to receive shipments of potassium nitrate and sulfur from Sicily. Horse-drawn wagons moved raw materials and gunpowder between the wharf and the powder works until the South Pacific Coast Railroad was built. Two Victorian mansions were built on a bluff overlooking the powder works as homes for the powder works superintendents. Company housing was available for powder mill workers, and a school opened nearby for their children.
California Powder Works began producing smokeless powder for firearms ammunition in the early 1890s. Peyton Powder, prepared at Santa Cruz under the direction of assistant superintendent William Peyton, had an unusual addition of ammonium picrate to the conventional double-base formulation of nitrocellulose and nitroglycerine. Peyton Powder was selected by the United States Army in 1893 for early cartridges for the new Krag-Jørgensen service rifle. The powder works also produced CPW Smokeless powder and loaded shotgun ammunition marketed as Native Son Cartridges after the army adopted W.A. powder in 1896 to avoid cartridge case corrosion caused by picric acid in the Peyton Powder.
California Powder Works manufactured powder for naval artillery. Initial production was prismatic brown powder, and the works later obtained a license to produce The United States Navy's patented nitrocellulose smokeless powder. Both powders were used by the Pacific and Asiatic Fleets, and for Pacific harbor and coast defense. The powder works operated a proving ground at Santa Cruz beginning 1892 using guns provided by the United States Inspector of Ordnance. Individual powder lots were test fired in the guns for which they were intended, including a 57mm QF 6 pounder Hotchkiss, a 6"/45 caliber Quick-Fire Rifle Model 1897, and an 8"/32 caliber Breach-Loading Rifle Model 1888.
Manufacture of dynamite at Hercules 
When dynamite was invented in 1867 and quickly became popular, a new dynamite plant was opened in 1869 near San Francisco in the area which later became Golden Gate Park. The danger of accidental explosions near a population center became unacceptable as San Francisco expanded; and land was purchased on Point Pinole in 1879 to shift manufacturing to the east side of San Francisco Bay. After initial purchases in 1868, DuPont had obtained 43% interest in California Powder Works by 1876, and financed Hercules Powder Company with Laflin & Rand Powder Company in 1882. The city of Hercules was named after California Powder Works' blasting powder, known as Hercules Powder, which in turn was named for the powerful Greek demigod, Hercules. Guncotton and nitroglycerine manufactured at Hercules were shipped to the smokeless powder plant at Santa Cruz.
Explosive powder manufacturing was an extremely dangerous endeavor at the time, and uncontrolled explosions were frequent. Hercules's isolated location at the time, plus its proximity to rail and water transportation along San Pablo Bay, made it an ideal choice. The explosives manufactured at Hercules played a significant and decisive role in the United States Army's efforts to contain the fires started by the 1906 San Francisco earthquake, as recounted by General Funston.
The Hercules site gained independence from Dupont as a result of federal anti-trust action in 1912. Hercules Powder Company contributed significantly to the production of explosives during both World Wars. By the Second World War, the plant had diversified to produce fertilizers and other chemical products. Eventually the facility was out-competed by foreign manufacturers, and the plant was closed in 1976. However, by this time the surrounding area was experiencing rapid growth as the commuter belt moved further outward from San Francisco. By the mid-1970s Centex Homes and other developers began to build new subdivisions and changed Hercules into the residential suburb as it was known up until the late 1990s. Back in the 1970s, Hercules was one of the first cities in the United States to develop a comprehensive Noise Element of the General Plan. This work included the production of noise contour maps for all major highways and arterial roads, as well as a city-wide mitigation plan. Considerable study has been made of the heavy metal lead accumulated as upper layer soil contamination from prior air pollution smokestack emissions from the California Powder Works operations from this era.
End of Santa Cruz operations 
The great explosion of 1898 started in the smokeless powder plant at 5:15 PM on April 26th. Santa Cruz was rocked by a series of heavy explosions which killed 13 men at the powder works and injured 25 more. Windows were broken in Santa Cruz, and flaming debris fell on Mission Hill. Many buildings used to house company employees were set afire and a community effort was required by residents of Santa Cruz to prevent fires from reaching powder magazines closer to the city. The explosion caused apprehension among Santa Cruz residents about the safety of operating the powder works so close to the city. Santa Cruz County closed the powder works school and required powder works employee housing facilities to be vacated.
California Powder Works became a DuPont subsidiary in 1903, and operated under the DuPont name after 1906. The wharf was removed when construction began in 1904 on the Neptune Casino at the Santa Cruz Beach Boardwalk. DuPont control of explosives manufacturing in the United States caused federal anti-trust action in 1912 requiring DuPont to distribute assets into three firms. Manufacture of blasting explosives was assigned to Atlas Powder Company. California Powder Works double-base smokeless powder patents were assigned to Hercules Powder Company's consolidated smokeless powder manufacturing facility at Kenvil, New Jersey. DuPont retained manufacture of black powder and single base smokeless powders including the powder being manufactured for the United States Navy. When the Panama Canal simplified transport to the Pacific Fleet, DuPont consolidated production facilities in New Jersey and terminated operations at Santa Cruz in 1914. Powder mill facilities were dismantled, and the property was sold in 1924. The two mansions occupied by powder works superintendents were abandoned and razed in the 1930s.
- "The California Powder Works". Santa Cruz Public Library Local History Articles. Retrieved 2011-11-21.
- Sharpe, Philip B. Complete Guide to Handloading 3rd Edition (1953) Funk & Wagnalls pp.146-149
- "Chronology of E.I. du Pont de Nemours & Co.". John Beverly Riggs. Retrieved 2012-02-26.
- "Laflin & Rand Powder Company". DuPont. Retrieved 2012-02-24.
- "How the Army Worked to Save San Francisco, by Brigadier General Frederick Funston (U.S.A.)". Cosmopolitan Magazine, July 1906. Retrieved 2007-03-29.
- M. Papineau and C. Michael Hogan, Air quality analysis of stationary sources, Hercules, Ca., Earth Metrics inc. (1976)
- "The Smokeless Powders of Laflin & Rand and their Fate 100 Years after Assimilation by DuPont". Klaus Neuschaefer. Retrieved 2012-02-26.