Through bioremediation, soil lightly contaminated with petroleum hydrocarbons is inoculated with a nutrient and an engineered bacteria that combine to break down the contaminants. The bacteria access the nutrients, which have attached to the hydrocarbons, and quickly and thoroughly degrade the contaminants. The average time needed to reduce contaminants to acceptable levels through bioremediation is approximately 7 to 14 days. The bioremediation process provides substantial cost savings when compared to thermal desorption or chemical fixation, and is typically used on soil with lower levels of contaminants. Materials treated through bioremediation are typically beneficially re-used as fill material.