The gas seeps are a significant air pollution source for Santa Barbara County and the oil slicks gradually lose volatiles and become tar balls, eventually washing onto southern California beaches.
(The gas seeps; are; a significant air pollution source for Santa Barbara County and the oil slicks gradually lose volatiles and become tar balls) (the oil slicks; gradually lose; volatiles) (the oil slicks; become; tar balls)
The gas seeps the oil slicks the oil slicks
are gradually lose become
a significant air pollution source for Santa Barbara County and the oil slicks gradually lose volatiles and become tar balls
volatiles
tar balls