Final answer:
The production step that results in the largest direct waste of petroleum is combustion, as this step involves inevitable energy losses and incomplete conversion of petroleum's potential energy into useful work.
Step-by-step explanation:
The step in the production of petroleum that results in the largest direct waste of petroleum is combustion. Combustion refers to the process where hydrocarbons found in petroleum products, such as gasoline, are burned to produce energy.
During this process, some of the energy content of the petroleum is not converted to useful work but is instead released as heat and exits through exhaust systems, leading to a waste of petroleum resources.
In contrast, the refining process which includes distillation, cracking, and reforming, is designed to maximize the yield of useful products from crude oil.
Similarly, extraction and distribution may involve some losses, but these are generally minimized through technological and procedural efficiencies.
Combustion, however, inherently involves energy losses, particularly in the transportation sector, which is heavily reliant on petroleum-based fuels.
Statistically, petroleum is a key energy source for transportation, with a significant percentage of it being allocated to this sector.
However, the direct contribution of petroleum to other domains, such as industrial processes, is also noteworthy, but it is within the act of combustion where the most direct waste occurs, as the complete potential energy is not realized during this step.