A total of 3,196 spills were reported in the Lower Galveston Bay watershed by the GLO during the period 1998-2007. As seen below, the number of spills reported by the GLO each year remained fairly constant with a maximum of 397 spills reported in 2001 and a low of 246 spills reported in 2005. Harris County reported the greatest number of total spills (1,772 spills or 55 percent of all spills), likely due to the large concentration of industrial and shipping facilities along the Houston Ship Channel. Galveston County ranked second with 1,192 total spills (37 percent of all spills). Galveston County also has a concentration of industrial facilities in Texas City and port facilities are located in Texas City and on Galveston Island. The total number of spills in Brazoria and Chambers counties (107 and 125 total spills respectively) was nearly ten times less than those reported in Harris and Galveston counties over the 1998-2007 reporting period. 

Oil spills are classified according to three types of sources: facility, vessel, or unknown. Vessel spills accounted for 1,377 spills (43 percent) of total spills. 1,178 spills (37 percent) were reported as being of unknown origin 641 spills (20 percent) were attributed to facilities.

Volume of Oil Spills

While analyzing the number of spills is one way to quantify oil spill data, it is also interesting to look at the nature of oil spills in the Galveston Bay system according to the volume of petroleum products spilled. For the period 1998-2007 a total of 383,897 gallons of petroleum products were reported by the GLO as spilled in the Lower Galveston Bay watershed. As seen below, Harris County and Galveston County had the largest reported spill volumes (224,311 gallons and 138,799 gallons, respectively).