crude raised to $14.56 per barrel. May: DOE announces $5 per barrel entitlement to importers of heating oil. Saudi Arabia announces intention to increase direct sales and to sell less through Aramco. Both announcements send prices higher. June 1: Phased oil price decontrol begins. Involves gradual 28 month increase of "old" oil price ceilings, and slower rate of increase of "new" oil price ceilings. June 26–28: OPEC raises prices average of 15 percent, effective July 1. October: Buy-Sell Program sales average more than from October 1979 through March 1980 - highest level since February 1976, due to emergency allocations. October: Canada eliminates light crude oil exports to U.S. refiners, except for those exports required by operational constraints of pipelines. November 4: Iran takes western hostages. November 12: U.S. President Jimmy Carter orders cessation of Iranian imports to U.S. November 15: Iran cancels all contracts with U.S. oil companies. December 13: Saudi Arabia raises marker crude price to $24 per barrel. The 1980s See: 1980-1989 world oil market chronology 1980 March 1: Windfall Profits Tax enacted. May: Saudi Light raised to $28.00 per barrel, retroactive to April 1. April–September: Buy-Sell Program allocations drop to average of for period April to September 1980.: September 17: Iraq breaks 1975 treaty with Iran and proclaims sovereignty over Shatt al-Arab waterway. September 23: Iraq invades Iran. Mutual bombing of installations. November 10: Iraq captures southern port of Khorramshahr. November 20–24: U.N. Gulf War mediator Olof Palme makes first unsuccessful peace shuttle between Tehran and Baghdad. December: Collapse of OPEC's pricing structure. Saudis use $32 per barrel marker, others use $36 per barrel benchmark. 1981 Saudis flood market with inexpensive oil in 1981, forcing unprecedented price cuts by OPEC members. In October, all 13 OPEC members align on a compromise $32 per barrel benchmark. Later, benchmark price is maintained, but differentials are adjusted. January: Iraq repels first major Iranian offensive. January 28: U.S. President Ronald Reagan lifts remaining domestic petroleum price and allocation controls originally scheduled to expire in September 1981. April: After meetings in Baghdad and Teheran, attempts by nine Islamic Conference leaders to mediate peace between Iraq and Iran fail. August: Windfall profits tax reduced. September 27–28: Iran defends its besieged port of Abadan, driving back Iraqi forces. October: OPEC reaches an agreement to unify crude price at $32 per barrel through 1982 and sets an ultimate price ceiling of $38 per barrel. November