Shrimp became a major industry during the early 1900s. Oyster shell was used as gravel for the railroads and roads, in the production of cement, and as the raw material source for the first major chemical industries along the Texas coast. Today the shell of Galveston Bay that took thousands of years to accumulate has been mined so heavily that even shell as a substrate for the oyster spat is at a premium. Galveston Bay was the site of great oil and gas discoveries in the early 1900s and soon became home to many refining companies. Today the production, refinement, and shipping of oil, gas, and their diverse by-products is a major resource for Houston, Bayport, and Texas City.
Refining is one of the most important reasons for growth of the Houston area.