The rig's operator, Occidental Petroleum, bought a direct insurance policy from Lloyd's underwriters, who then passed part of their shares of the risk on to other syndicates via reinsurance. Those reinsurers then in turn reinsured part of the risk out to other reinsurance underwriters within Lloyd's (known as "retrocessionaires"), and so on. Consequently, many syndicates, especially those writing a large amount of excess of loss reinsurance, became exposed to the same claim multiple times through multiple layers in the spiral. Other catastrophes, including Hurricane Hugo and the "Exxon Valdez" oil spill in 1989, also went into the spiral.