Some benzene levels were measured near the Gulf of Mexico in the range of 3,000 to 4,000 ppb -- up from the normal 0 to 4 ppb. Benzene gas is
water soluble and is a carcinogen
at levels of 1,000 ppb according to the EPA. Upon using a GPS and depth finder system, experts have discovered a large gas bubble, 15 to 20 miles wide and tens of feet high, under the ocean floor. These bubbles are common.