Parcels are appraised "as if clean." Many appraisers are not qualified to detect the presence of contamination, therefore, some sites may be appraised "as if clean" even though they are impacted by contamination. The value of contaminated real estate may not be accurately estimated by simply deducting the estimated remediation or compliance cost from the unaffected value. Other factors may influence value, including a positive or negative perceived impact on marketability (stigma) and the possibility of change in the highest and best uses. After the original "as if clean" appraisal is obtained, an appraiser with contamination expertise should be considered for some parcels. Districts should contact ROW for information on obtaining appraisal experts. Additionally, expert technical services for estimating corrective action costs may be obtained through ENV statewide environmental contracts.