There are several treatments available for the remediation of petroleum hydrocarbon-contaminated soil. Battelle Marine Sciences Laboratory (MSL) and the Washington State Department of Transportation (WSDOT) conducted a 4-month experiment to compare the efficacy of three different biological approaches - mycoremediation, bioremediation, and enhanced bacterial remediation - used under open environmental exposure to treat three excavated, aged oil-contaminated soils stored at the WSDOT Maintenance Yard, Bellingham, Washington. At the end of the experiment, the results were not conclusive in distinguishing the outcome of the various treatments; none appeared to meet the prescribed criterion for success. The inconclusive nature of the chemical results is largely attributable to the unexpected heterogeneity of the test soils; that is, there was extremely patchy distribution of contaminant within test mounds, and extreme variability of initial contaminant level among test mounds within each soil type. Another important factor was that the petroleum hydrocarbons in the soils under study were found to be very weathered; oils in this condition could require a longer time period for remediation than that required for fresh, unweathered oils. This report contains the results of the study of mycoremediation of petroleum hydrocarbons and other contaminants in soil and other substrata. Mycoremediation employs selected, cultured fungal mycelia to remove/degrade environmental contaminants.