On September 16, 2010, Hurricanes Igor and Julia made it to Category 4 status. This marked the first time since September 16, 1926 that two Category 4 hurricanes existed in the Atlantic at the same time for just six hours. September 16, 1999 marked a day of unprecedented devastation for North Carolina. Hurricane Floyd unloaded 20 inches of rain with flooding never before experienced in the Carolina's. Sewage, flowing from the Cape Fear River, stretched 50 miles past Wilmington and 20 miles into the Atlantic. Municipal treatment plants overflowed with fears of environmental disasters from gas station chemicals, factories spewing chromium along with mercury, hog and chicken waste. Since '99, eco-systems were surprisingly flushed free.  Carolinians remember 1999 and Hurricanes Dennis, Floyd and Irene. Recovery operations from those storms lasted through the end of 1999. The nation's largest lagoonal estuary at Pamlico Sound in North Carolina was also altered. For six weeks, the entire water content of Pamlico Sound was replaced by flooding. The University of North Carolina's Institute of Marine Sciences released its research on the effects of the storms. Pamlico Sound has only four small inlets that restrict water exchange to the sea. What occurred over the six-week period normally would take a year, displacing three-fourths of the sound's volume. Salinity declined by two-thirds and the sound's annual intake of nitrogen increased more than 50 percent. Pamlico Sound is a valuable mid-Atlantic fish nursery. Numerous marine organisms died  because of the storms.