Oil sheen off California possibly caused by natural seepage from ocean floor, Coast Guard saysNatural oil seep suspected for oil sheen off California coastLab tests inconclusive in identifying oil source
O.C. oil spill was caused by natural ocean seepage, not drilling, officials sayNatural oil sheen off Huntington Beach resulted from ocean floor seepage.Technology used to identify source of oil in the ocean and differentiate between naturally occurring or man-made causes.