addition of commercial fertilizers, monthly tilling (to add oxygen), and watering (to maintain 10–15% moisture content). Treatment is considered complete when hydrocarbon levels reach concentrations specified by regulatory agencies; not all agencies employ the same acceptability standards. Water and soil are monitored periodically to confirm that no adverse soil or groundwater impacts have occurred, and records of the source and disposition of the remediated soil are maintained. Estimated treatment costs, which include transportation, spreading, amendments, and monitoring, are about $4–5 per cubic yard. When the treated material is recycled as backfill, net costs are about $1 per cubic yard. Capital costs (not included in the treatment cost estimates) were recovered within the first eight months of operation (Cole and Mark 2000). Implementation Considerations: Advantages of land farming include its simplicity and low capital cost, the ability to apply multiple waste loadings to the same parcel of land, and the potential to improve soil conditions. Concerns associated with land farming are its high maintenance costs (e.g., for periodic land tilling, fertilizer); potentially large land requirements; and required analysis, testing, demonstration, and monitoring. Elevated concentrations of hydrocarbon in drilling wastes can limit the application rate of a waste on a site. Wastes containing salt must also be applied to soil only with care. Salt, unlike hydrocarbons, cannot biodegrade but may accumulate in soils, which have a limited capacity to accept salts. If salt levels become too high, the soils may be damaged and treatment of hydrocarbons can be inhibited. Salts are soluble in water and can be managed. Salt management is part of prudent operation of a land farm. Another concern with land farming is that while lower molecularweight petroleum compounds biodegrade efficiently, higher molecular weight compounds biodegrade more slowly. This means that repeated applications can lead to accumulation of high molecular weight compounds. At high concentrations, these recalcitrant constituents can increase soil-water repellency, affect plant growth, reduce the ability of the soil to support a diverse community of organisms, and render the land farm no longer usable without treatment or amendment. Recent studies have supported the idea that field-scale additions of earthworms with selected organic amendments may hasten the long-term recovery of conventionally treated petroleum contaminated soil. The burrowing and feeding activities of earthworms create space and allow food resources to become available to other soil organisms that would be unable to survive otherwise. The use of earthworms in Europe has