Natural seepage is believed to account for 60% of the oil in North American waters. The National Academies of Science in a 2002 report estimated that 260,000 tons of oil were input into North American maritime waters annually, 1990-1999. 160,000 tons were from natural seepage.
Oil seeps occur throughout the Gulf of Mexico. In a 1972 paper titled Natural Hydrocarbon Seepage in the Gulf of Mexico
, Researchers from Texas A&M University said this about the history of this seepage:
“Archaeological reports indicate that the Karankawa Indians were using tar in their pottery making in pre-Columbian times. Survivors of DeSoto’s group used tar found along the Texas-Louisiana coast to caulk their boats.
From 1902 to 1909 heavy oil slicks were noted in an area about 100 miles south of the Louisiana coast. Oil spouting into the air was reported in the same area in 1909. Oil ponds off the Sabine area are reported in a USGS publication in 1903.
Reports of seeps in the Gulf are numerous, and the Department’s study has located several general areas of seepage within and around the Gulf of Mexico.”
A Department of Energy website
details studies that estimate that there may be as many as 5,000 active seeps in the northern Gulf of Mexico. In the Green Canyon area of the Gulf, they estimated at least 900 individual seeps.
In a paper presented at the 2000 Ocean Sciences Meeting in San Antonio, Texas, and titled Estimates of Total Hydrocarbon Seepage into the Gulf of Mexico Based on Satellite Remote Sensing Images
, one researcher estimated that 500,000 barrels of oil seep into the Gulf each year.