Many tar balls have been spotted along the Santa Monica Shoreline on Wednesday, May 16, 2012. According to the Minerals Management Service, tar and tar seepage are natural parts of the environment. It is evidenced that oil, tar and gas have occurred throughout the coastlines for thousands of years, and are particularly prevalent along the California coastline due to its mountainous regions. Scientists often cannot tell the difference between oil from naturally-occurring seeps and oil from offshore spills. Along the California coastline, there is a large amount of oil seeping naturally from the rocks under the ocean.