Whales were hunted for their oil, which was used for lighting, but as demand increased the whale population declined. Samuel Kier discovered oil could be extracted from salt mines as a byproduct. George Bissell and Benjamin Sillman realized kerosene could be distilled from crude oil. This led to the founding of the Pennsylvania Rock Oil Company and Colonel Drake's first oil well in 1859, launching the petroleum industry. John D. Rockefeller founded Standard Oil, which came to control 90% of the US market by 1890. Developments in gasoline-powered cars and jets increased demand for oil as a transportation fuel.