Used industrial oil is classified as dangerous waste material according to the EWL (European Waste List) code, and, in fact, oil that comes from vehicles and machinery is one of the most highly-contaminating waste residues out there because the lubricants are consistently exposed to high temperatures within the motors and machinery they operate in, deriving in heavy metals and toxic substances.

Used industrial oil has been classified as a dangerous waste material and is regulated by RoyalDecree 679/2006, modified by ARM Order 795/2011 and through the establishment of  Law 7/2022 in which the scope of environmental responsibility was widened, further encompassing the assurance of correct waste management.

If a company, for example, were to simply dump their used oil as opposed to leaving it in the hands of a residual waste management professional (as they should do), there would be both economic consequences to these actions, and grave environmental consequences. Both groundwater and soil fertility would be adversely affected, with just one liter of dumped oil contaminating the equivalent of an entire football field.