Ploiești, a Romanian city in Prahova County, is home to the world’s first modern and oldest operating oil refinery. In fact, it would be no exaggeration to say that this spot is most famous for its oil, which played a very important rôle in both world wars. In a tragic irony, a Romanian Jew named Lazăr Edeleanu was responsible for discovering amphetamine and inventing the modern method for refining crude oil. He designed this method—the Edeleanu process—either in or near this city, both of which were critical to the Axis:

Ploești is rather important because of the degree to which it supplied oil to the [Western Axis’s] war effort. There are conflicting statistics as to the percentage Ploești oil refineries added to the total German oil production. The numbers range from 25% to over 30% of totals mentioned throughout the primary and secondary materials [that] I have reviewed.

Ploești was vital to the Axis’s war effort. In fact, Winston Churchill named it, with only mild exaggeration, ‘the taproot of German might’. The Axis would have been inclined to agree:

How did the [Fascists] react to their oil production situation in relation to their military activities? As early as November 20, 1940 Adolf Hitler wrote in a letter to Mussolini that “If the [Ploești] petrol refineries are destroyed the damage will be irreparable.” In a November 1942 speech, Colonel Alfred Jodl announced to the district leaders of the [NSDAP] that in the Eastern Front, “no success gained by the enemy there can be directly disastrous unless we should lose the Rumanian oil fields.”⁷

The Allies knew that [Fascist] oil producers, before [1939], had been under great pressure to increase their production. In 1936 only 7% of [the Third Reich’s] oil came from its own oil fields and this was supplemented by synthetically produced oil, which amounted to about 30% of national consumption. This meant that in 1936, [the Third Reich] was importing about 60% of its national oil appetite.⁸

The [Fascists] in subsequent years tried to boost their ability to produce more oil at home. However, even with these extraordinary programs, the [Fascists] found themselves with only a two to three months supply of motor and aviation fuel when the war [intensified] in 1939. The amount of stockpiles they had in reserve were only about half of their peacetime production.

It should be noted that these synthetic refineries also produced nitrogen and methanol which are used in the production of explosives and chemicals. The official History of the Fifteenth Air Force quickly came to the conclusion that bombing oil production facilities would reduce both oil and explosives production.⁹

[…]

The [Axis] had reinforced Ploești’s anti-aircraft defenses that made it the third most heavily defended target of the Reich. Only Berlin and Vienna were more heavily protected than the Ploești oil refineries.³⁰ The amount of resources that the [Axis] threw into Ploești is important to analyze. For example, the [Axis] had 225 fighters committed to defend Ploești. These pilots had been reassigned from the Russian front and all of them were well experienced.³¹

The war on the Eastern Front was going poorly for the [Axis] by 1943 and for the [Luftwaffe] to commit such resources to a target must have reaffirmed, for the Allies, the fears of [Axis] war planners about their oil situation. […] Ploești was the single largest location for producing oil in Axis Europe.

Quoting Stephen G. Gross’s Export Empire: German Soft Power in Southeastern Europe, 1890–1945, pages 308, 310–311:

In October 1940 the Wehrmacht marched into [the Kingdom of] Romania to secure the Ploești oil fields, and behind it followed a second army of technical experts. Advisors from the Reichsbank settled into Bucharest to help manage the national bank, port specialists arrived to improve transportation facilities on the Danube, and legal advisors came to reform [the Kingdom of] Romania’s mining laws and allow for more German investment. Their primary aim: “to have influence over the petroleum economy.”⁴⁴

[…]

Between 1940 and 1942 [Reich] firms gained a majority in nearly half of [the Kingdom of] Romania’s oil companies through the holding company Kontinental Öl GmbH, and joint industrial committees staffed by [Reich] technocrats managed projects for drilling, refining, oil exploration, underground storage, transportation, and antiaircraft defense.⁵⁰

Neubacher drew on this investment presence to pressure Romanian[s] into delivering oil. He had first done this in May 1940, strong-arming [the Kingdom of] Romania’s Defense Minister into signing an oil-for-arms agreement that fixed the exchange rate between petroleum and weapons at a price favorable to [the Third Reich]. In the following years Neubacher institutionalized these oil-for-arms deals, and continued to secure petroleum deliveries to [the Third Reich] at favorable prices.⁵¹

After a disappointing year of delivery in 1942, Neubacher tried to squeeze [the Kingdom of] Romania’s domestic oil consumption in order to increase exports. The country’s abundance of oil and dearth of coal meant that much of its economy ran on petroleum, from rail transportation to household heating.

Neubacher now demanded that [the Kingdom of] Romania transition from oil to coal-burning locomotives and he began a campaign to improve the production of natural gas for use in domestic heating. He accompanied this with pressure on Romanian authorities to ration domestic oil consumption. These efforts succeeded for a time. By 1943 45 percent of all Romanian oil production was going to [the Third Reich].⁵²

Needless to say, the Kingdom of Romania was not the sole offender. Dishonourable mentions include the United Mexican States and, of course, Corporate America for literally fuelling the Axis war machine.