Occidental Petroleum Corporation (often abbreviated Oxy in reference to its ticker symbol) is a multinational petroleum and natural gas exploration and production company headquartered in Houston, Texas with operations in the United States, the Middle East, and Latin America. The company is ranked 722nd on the Forbes Global 2000. and 278th on the Fortune 500.

In 2016, the company was the 3rd largest petroleum producer and 21st largest natural gas producer in Texas.

Occidental Petroleum was founded in 1920 in California. In 1957, Armand Hammer was elected president and chief executive officer of the company after he acquired a controlling stake in the firm for tax reasons. In 1961, the company discovered the Lathrop Gas Field in Lathrop, California.

In the 1960s, the company expanded internationally with operations in Libya, Peru, Venezuela, Bolivia, Trinidad, and the United Kingdom. Occidental won exploration rights in Libya in 1965 and operated there until all activities were suspended in 1986 after the United States imposed economic sanctions on Libya.

In 1968, the company entered the chemical business with the acquisition of Hooker Chemical Company, 26 years after the contamination at Love Canal.

In 1971, the company received permission to develop an oil refinery in Canvey Island in Essex. The company began construction but stopped in 1975 as a result of the 1970s energy crisis. The site remained derelict; the tanks and the chimney were subsequently demolished. Only some concrete foundations and the river jetty remain extant.

In 1972, the company was one of the first companies to research developing oil shale.

In 1983, the company and Ecopetrol, the state-owned oil company, discovered the giant Caño Limón oilfield.

In April 1988, the company acquired Cain Chemical for $2 billion.

On July 6, 1988, an explosion and subsequent inferno on the company's Piper Alpha platform in the Scottish North Sea, resulted in 167 fatalities in what remains the world's most deadly offshore disaster.

In September 1988, the company former a joint venture with Church & Dwight, which makes Arm & Hammer products, for a potassium carbonate plant at Muscle Shoals, Alabama.

In 1990, Armand Hammer died and Dr. Ray R. Irani became chairman and chief executive officer of the company.

In 1991, the company sold its stake in IBP, Inc., one of largest producers of beef and pork products in the United States.

In 1993, the company sold its remaining coal operations.

In February 1996, the company announced layoffs of 450 people in its chemical division.

In July 1996, the company sold its interest in 3 oilfields in the Congo to the Congolese government for $215 million.

In 1997, the company paid $3.65 billion to acquire the Elk Hills Oil Field.

In 2005, Occidental and partner Liwa won eight out of 15 exploration spots on the EPSA-4 auction, making both companies among the first to enter the Libyan market since the United States lifted its embargo on Libya.

In October 2005, the company acquired Vintage Petroleum for $3.8 billion.

In 2006, the government of Ecuador seized the company's interest in block 15 of the Amazon Rainforest in Ecuador, forcing the company to take a $306 million after-tax charge. In 2016, the government agreed to pay USD$980 million in restitution to the company for the seizure, down from the original award of USD$1.77 billion. The agreement was based on a 2012 arbitration award from the International Center for Settlement of Investment Disputes (ICSID).

In 2007, the company's compensation policies came under scrutiny after it was announced that Irani received $460 million in compensation in 2006. In May 2011, Irani retired as CEO after CalSTRS and Relational Investors, two major shareholders, objected to the company's compensation policies for top executives. President Stephen I. Chazen was named CEO to replace Irani and in 2013, shareholders ousted Irani as chairman. Despite his outlandish compensation, during Irani's tenure, the company has grown from a collection of unrelated businesses to one that focuses on oil and gas and the market capitalization of the company went from $5.5 billion to $80 billion.

In 2008, the company acquired a 10% stake in Plains All American Pipeline. The company also acquired assets from Plains Exploration & Production for $1.3 billion.

In February 2009, the company closed its Louisville OxyVinyl polyvinyl chloride production plant.

In October 2009, the company acquired Citigroup's controversial Phibro energy-trading business, for its net asset value of approximately $250 million. The unit was managed by Andrew J. Hall who received compensation of approximately $100 million per year in 2007 and 2008. After the acquisition, the division reported its first losses since the 1990s. In 2016, Phibro was wound down and sold.

In December 2010, the company acquired shale oil properties in the Williston Basin in North Dakota for $1.4 billion. These assets, as well as other assets acquired by Oxy in the Williston Basin, were sold in 2015 for $600 million.

In December 2010, the company sold its proven and probable reserves of 393 million 393 million barrels of oil equivalent (2.40×10 GJ) in Argentina to Sinopec, a subsidiary of China Petrochemical Corporation. It also acquired properties in South Texas and North Dakota for $3.2 billion.

In January 2011, Occidental partnered with Abu Dhabi's state oil company in developing the Shah Field, one of the largest natural gas fields in the Middle East, through a joint venture known as Al Hosn Gas. Al Hosn Gas became operational in 2015.

In 2013, Oxychem sold its investment in Unipar Carbocloro for R$550 million.

In September 2014, the company moved its headquarters to Houston, Texas.

In November 2014, the company sold its 50% interest in BridgeTex Pipeline Company, owner of a 300,000 barrel-per-day crude oil pipeline system that extends from Colorado City, Texas to Texas City, Texas, for $1.075 billion.

In December 2014, the company distributed 80.5% of its shares in California Resources Corporation, the largest producer of oil and natural gas on a gross-operated barrels of oil equivalent basis in California, to Occidental shareholders and distributed its remaining stake to shareholders in March 2016.

In October 2015, the company completed the first phase of a $500 million carbon dioxide flooding project in Hobbs, New Mexico.

In January 2016, the company sold an office tower in Dallas, Texas for $95 million.

In May 2016, Vicki Hollub, who had worked at Occidental since 1981 and joined the board in 2015, became the chief executive officer of the company, the first female to serve as chief executive officer of a major U.S. oil and gas company.

In March 2017, the company and its 50/50 joint venture partner Mexichem began operations of a a 1.2-billion-pound per year capacity ethylene cracker at the OxyChem plant in Ingleside, Texas, along with pipelines and storage at Markham, Texas.

In May 2017, Christopher Stavros, the chief financial officer of the company, retired.

In June 2017, the company sold land in the Permian Basin for $600 million and used the proceeds to acquire other assets in the area.

The company's oil and gas operations are concentrated in three geographic areas: the United States, Latin America, and the Middle East.

As of December 31, 2016, Occidental had 2.406 billion barrels of oil equivalent (1.472×10 GJ) of oil equivalent net proved reserves, of which 56% was petroleum, 17% was natural gas liquids, and 27% was natural gas.

In 2016, the company had production of 630 thousand barrels of oil equivalent (3,900,000 GJ) per day.

In 2016, Occidental's United States operations produced 302 thousand barrels of oil equivalent (1,850,000 GJ) per day, representing 48% of the company's worldwide production. This includes approximately 269 thousand barrels of oil equivalent (1,650,000 GJ) barrels of oil equivalent per day in the Permian Basin, where Occidental is the largest operator and oil producer, and 33 thousand barrels of oil equivalent (200,000 GJ) per day of production in its mid-continent operations in Colorado and South Texas. The 269,000 barrels of oil equivalent per day in the Permian Basin includes 124,000 barrels of oil equivalent per day from "unconventional" resources through Permian Resources and 145,000 barrels of oil equivalent per day using a technique called enhanced oil recovery (EOR). EOR technology used in the Permian includes water flooding and carbon dioxide flooding, whereby carbon dioxide is injected into underground formations to extract the oil and gas.

Occidental's oil and gas operations in the Middle East are in Oman, Qatar, and the United Arab Emirates. The region produced 294 thousand barrels of oil equivalent (1,800,000 GJ) per day, representing approximately 46% of 2016 total worldwide production. The region also held 28% of the company's proved reserves in 2016.

Occidental is the largest independent oil producer in Oman. In Qatar, Occidental is the second-largest oil producer offshore and is a partial owner in the Dolphin natural gas project, which delivers gas to Oman and the United Arab Emirates.

In Latin America, which accounted for 5% of total production in 2016, Occidental operates in Bolivia and Colombia, where it operates the Caño Limón oilfield. Occidental's share of production from its Latin America assets was approximately 34 thousand barrels of oil equivalent (210,000 GJ) per day in 2016, which included 33 thousand barrels of oil equivalent (200,000 GJ) per day from Colombia.

OxyChem manufactures polyvinyl chloride (PVC) resins, chlorine and caustic soda used in plastics, pharmaceuticals and water treatment chemicals. Other products manufactured by the company include caustic potash, chlorinated organics, sodium silicates, chlorinated isocyanurates and calcium chloride. OxyChem has manufacturing facilities in the United States, Canada and Chile. In a joint venture with Church & Dwight, OxyChem owns Armand Products Company, which sells potassium carbonate and potassium bicarbonate.

Occidental Petroleum began operations in Libya in 1965 and operated there until sanctions were imposed in 1986 by the United States. The company was one of the first American companies to resume negotiations in Libya after U.S. sanctions were lifted in 2004. In 2008, the company, along with five other oil companies, was criticized for hiring Hogan Lovells to lobby to exempt Libya from a law written by U.S. Senator Frank Lautenberg (D-NJ) to assist American terror victims in seizing assets of countries found culpable in terror attacks, such as the Libyan bombing of the Pan Am flight in Lockerbie in 1988. and to remove a provision in the Dodd–Frank Wall Street Reform and Consumer Protection Act that requires disclosure of payments to foreign governments. In early 2011, the company ceased exploration activities and production operations in Libya due to the growing civil unrest in the country and U.S. sanctions. In June 2011, the U.S. Securities and Exchange Commission (SEC) requested information from the company, ExxonMobil and ConocoPhillips related to the Libyan Investment Authority (LIA), an investment firm controlled by Libyan leader Muammar Gaddafi. United Kingdom prosecutors, in cooperation with the SEC, have undertaken similar investigations of multiple oil companies during this same period to determine if there were any violations of international bribery laws. The Libyan Investment Authority's investments were frozen by the U.S. government in early 2011 following the Gaddafi regime's attacks on Libyan civilians. In 2016, the company ceased operations in Libya.

In 2017, the company was ranked 55th on the Carbon Majors Report, a list of the Top 100 producers and their cumulative greenhouse gas emissions from 1988-2015.

In 2016, 24% of the company's production was from a method of oil extraction called carbon dioxide (CO2) flood technology, or carbon sequestration for enhanced oil recovery, which is a more environmental-friendly method of oil extraction because it could stall the accumulation of carbon dioxide in the atmosphere by instead injecting it into the ground. The company has stated that this is one way in which it reduces emissions.

The company is a participant in a large reclamation project in the southeastern United States at Copper Basin. The company acquired the land in 1982, not engaging in mining activities at Copper Basin, including the North Potato Creek Watershed, which were used to mine copper and sulfur dating back to the 1800s. In 2001, Occidental, Glenn Springs Holdings federal and local agencies came to an agreement to clean up Copper Basin and restore the water quality of its creeks.

In 1942, Hooker Chemical and Plastics began disposing chemical waste in the Love Canal region. Other companies, as well as the military, had used it as a chemical disposal site since the 1920s. In 1947, Hooker Chemicals became the owner and the sole user of the land. In 1952, the site was filled to capacity and closed off. Later in the 1950s, the local school board requested Hooker, after threatening to resort to eminent domain, sell the land. The school board intended to build a school on an unused area of the dump. Hooker Chemical leased the land to the school board in 1953.

A school was built on the site, and later a middle-class residential district was built upon the land adjacent to the site. The construction broke through the 4-foot (1.2 m) clay seal containing the waste. In 1968, Hooker Chemical was purchased by Occidental Petroleum. In 1978, residents became concerned about unusual health issues in the Love Canal region, including high rates of cancer and birth defects. This subsequently became a national news story, and in 1980, president Jimmy Carter declared a federal emergency in the area. Residents were eventually relocated, and Occidental paid $129 million in restitution.

On October 11, 2008, an accidental spill of oleum, a chemical similar to sulfuric acid, occurred at INDSPEC's facility in Petrolia, Pennsylvania. The accident caused contamination of the ventilation system and a cloud of toxic gas in the Petrolia sky. 2,500 residents of the area were asked to evacuate for the day.

Occidental met with substantial resistance from 1992 to 2001 when it tried to drill for oil in the territory of the U'wa people in northeast Colombia. The locals were concerned about environmental damage and feared that development would bring strangers and invite violence to the region. There also were tribal beliefs that oil is the "blood of the earth" and should not be removed. They believed that oil infrastructure would be a target for violent leftist guerilla fighters in the country. In 2002, after years of shareholder resolutions, legal battles, protests, and a failed test well, the company abandoned the project. Repsol YPF took over the project.

On December 13, 1998, seventeen civilians, including 7 children, were killed when the Colombian Air Force (CAF) dropped a cluster bomb in the hamlet of Santo Domingo, Colombia, after AirScan, Occidental's security contractor, from a private aircraft, incorrectly identified it as a hostile guerrilla target. Groups such as FARC and the National Liberation Army were active in the area. Three employees of AirScan were flying the Skymaster plane from which they provided the Colombian military with the coordinates to drop the bombs. The operation had been planned by the CAF and AirScan at Occidental's complex in Caño Limón. A lawsuit was attempted in April 2003 against Occidental by Luis Alberto Galvis Mujica, a witness and survivor of the accident. Plaintiffs claims were dismissed by the trial court. The dismissal was appealed to 9th U.S. Circuit Court of Appeals, which sent the case back to the trial court to resolve a single issue. The trial court declined to reconsider the case, thereby reinstating the dismissal. The case is once again on appeal.

On May 10, 2007, a group of 25 indigenous Achuar Peruvians filed suit against Occidental, demanding clean-up and reparations for environmental damages allegedly caused by Occidental over 30 years. The plaintiffs claimed that the company violated the industry standards and the environmental regulations by dumping a total of 9 billion barrels (1.4×10^ m) of toxic oil by-products in watersheds used by the Achuar people to fish, drink, and bathe. This environmental damage was alleged to have caused premature deaths and birth defects. A 2006 study by Peru's health ministry tested 199 people in seven affected communities, and found that all but two had levels of cadmium in their blood above safe levels.

The Achuar were represented by EarthRights International and the law firm Schonbrun DeSimone Seplow Harris & Hoffman LLP.

On March 3, 2010, EarthRights International (ERI) argued to the Ninth Circuit Court of Appeals that the landmark environmental and public health case brought by indigenous Peruvian Achuar and the U.S. NGO Amazon Watch against Los Angeles-based oil giant Occidental Petroleum (Oxy), Maynas Carijano v. Occidental Petroleum, should be litigated in Los Angeles, where Oxy is headquartered.

The appeals court overturned the prior decision and in 2013, the United States Supreme Court refused to hear the company’s arguments against a domestic trial.

In March 2015, Occidental Petroleum made an out-of-court settlement for an undisclosed sum with the funds to be used for health, education and nutrition projects in five Achuar communities (Antioquía, José Olaya, Nueva Jerusalén, Pampa Hermosa and Saukí) in the Corrientes river basin in Peru’s northern Amazon.

Occidental has disclosed its contributions to political action committees, lobbyists, and industry trade groups on its website.

In 2005, the company was among 53 entities which contributed the maximum of $250,000 to the second inauguration of President George W. Bush.

The company also donated between $10,000 and $25,000 to the Clinton Foundation.

In 2016, California Resources Corp. created the group Powering California, which teamed up with the Los Angeles Times' “content solutions” team to promote oil-industry messaging.

In 2016, as the California legislature considered extending climate policies, Powering California released a series of videos praising oil and attacking clean energy sources. One of the videos [1] asserts that “renewable energy can’t replace oil,” [2] claims wind energy is “expensive,” and declares that “oil and natural gas are woven into the fabric of America.” Another video features interviews with paid actors touting California’s oil and gas industry.

Occidental's coal interests were represented for many years by lawyer and former U.S. Senator Albert Gore, Sr., among others. Gore, who had a long-time close friendship with Hammer, became the head of the subsidiary Island Creek Coal Company, upon his election loss in the United States Senate. Much of the company's coal and phosphate production was in Tennessee, the state Gore represented in the Senate, and Gore owned shares in the company. The company liquidated its coal assets in 1993 after Hammer died.

Former Vice President of the United States Albert Arnold Gore, Jr. received much criticism from environmentalists, when he inherited shares in the company after the death of his father. However, Gore did not exercise control over the shares, and they were sold when the estate closed.

In 1998, the U.S. government sold the Elk Hills Oil Field to Occidental for $3.65 billion. According to the government, the reserve was no longer strategically necessary, and the reserve was sold to reduce the national debt and the size of the government. To ensure competition, the field was sold in segments and offered to multiple bidders. Critics cited Vice President Al Gore's involvement with the company as evidence of graft.

OxyChem has achieved Star Status under OSHA's Voluntary Protection Programs as being among the safest work sites in the U.S.

On July 6, 1988, Occidental's Piper Alpha offshore production platform in the UK North Sea was destroyed when an out of service gas condensate pump was started with its pressure safety valve removed. The subsequent gas leak, explosion and fire resulted in the deaths of 167 workers in what remains the world's deadliest offshore disaster.

In 1984, David Murdock owned about 5% of the company's shares. When Murdock called on the management to take measures to increase the share price, it chose to pay greenmail to buy back shares from him at $40.10, while the market price was $28.75.