On July 14, 1953, the freighter S.S. Jacob Luckenbach collided with another vessel and sank in the Gulf of the Farallones. As it decayed on the ocean floor, it leaked oil and became the source of many oil spills, primarily during large winter storms when currents rocked the vessel. Major oiling events have occurred every few winters since at least 1973-74. It was not until January 2002 that these mystery spills were linked to the Luckenbach. These spills manifested themselves in the appearance of oiled seabirds on beaches from Bodega Bay to Monterey Bay. Oil chemistry analysis has confirmed the presence of Luckenbach oil on dead birds for every winter since 1992-93 (the earliest date for which samples are available).