The two World Wars and the worldwide depression in the 1930s had an enormous impact on the structure, organization and philosophy of APC and its subsidiaries. World War I was a difficult time for APC in Belgium. As the Netherlands had remained neutral, APC was able to continue importing oil products from the United States. The devastating war in Belgium destroyed almost all of the company's depots and all the vehicles were either confiscated or stolen. Losses at sea were also heavy. Several tankers were sunk with all hands, including the Chester in 1915. The Antwerpen was torpedoed in 1916, and the Charlois, one of the Dutch APC tankers, disappeared in 1917 under mysterious circumstances.

The economic revival of the 'roaring twenties' came to an abrupt halt with the world crisis in the 1930s. This was a decade of recession. The Dutch branch of APC underwent drastic reorganization, with the number of depots reduced from 180 in 1933 to 30 in 1938.

The situation was somewhat more favorable in Belgium where the reorganization was done locally rather than nationally because the economic situation was better in some areas than in others. In 1937, APC divided the Belgian market into four major areas: Brussels, Antwerp, Ghent and Charleroi & Liège. The company changed its name to the Standard American Petroleum Company.

In the Netherlands, APC changed its name to Standard Amerikaansche Petroleum Compagnie N.V. in 1938. The name changes were made because the majority of the APC shares were now in the hands of the Standard Oil Company (New Jersey).

Not only World War I, but also World War II hit the business world very hard. Neither of the Standard Companies was spared. In the first weeks of war, fighting and bombing caused considerable damage to the installations in Antwerp, Rotterdam and Amsterdam. The three cities were either heavily damaged or totally destroyed and many employees lost their lives. Several tankers were sunk in oceans around the world. By the end of the war, there was little or nothing left of either company. The vehicles and tankers had been requisitioned. To cut a long story short, the company's operation was seriously disrupted by the time it emerged from the war years.

One thing was certain, everything had to be rebuilt from scratch. There were still employees with experience and loyalty, and there was the support of the parent company in the United States. So operations were quickly resumed. Up until the early 1970s, the sky was the limit. The economy was booming. Esso made the most of it and invested heavily. After all, returns were guaranteed.

In 1953, the company that had incorporated Esso into its name put into operation a new, state-of-the-art refinery at the docks on the Schelde River in Antwerp. A few years later, at the peak of the post-war economic boom, Esso also built a new refinery in the Netherlands, in Rotterdam. These investments in Belgium and the Netherlands changed Esso from an importer to an exporter of oil products.

In the Netherlands after the war, and as a shareholder in the Nederlandse Aardolie Maatschappij, Esso also became involved in the exploration and extraction of crude oil using nodding donkeys around Schoonebeek in the Province of Drenthe. After the discovery of the large gas bubble in Slochteren in the Province of Groningen at the end of the fifties the emphasis shifted to production, sales and distribution of natural gas.