The well that blew out in the 1969 Santa Barbara oil spill was on Platform A.
Platform A, operated by Union Oil in the Dos Cuadras Offshore Oil Field, was the site of the catastrophic blowout on January 28, 1969. Crews were drilling the fifth well, A-21, when high-pressure oil and gas escaped. Although workers capped the wellhead, underground fluids forced their way through weak surrounding formations and erupted from the seabed.
The spill spread across the Santa Barbara Channel and polluted beaches along Southern California. Estimates commonly place the release at roughly 80,000 to 100,000 barrels of crude oil. Thousands of birds and marine animals were killed, and the disaster intensified public opposition to offshore drilling.
Platform Holly is a separate platform in the Ellwood Oil Field, while Platforms B and C were other installations in the Dos Cuadras field. The spill became an important catalyst for modern environmental politics, helping build momentum for the first nationally coordinated Earth Day on April 22, 1970, and for stronger environmental regulation.