The Heating Oil Tank Program has developed a spreadsheet model designed to estimate simple site-specific screening levels for volatilization from soil to indoor air at heating oil tank sites. As illustrated in the figure below, the model assumes that all of the volatile contaminant mass in a known volume of contaminated soil enters a building and mixes with the indoor air which is being replaced at a constant exchange rate. The infiltration and mixing occurs over the entire exposure period.
Mass of Contaminant divided by volume of contaminated air equals estimated concentration

This spreadsheet is intended for use by Oregon DEQ staff, and is offered for public use without guarantees or support by the Department. The Department may decide to use risk-based screening levels other than those generated by this spreadsheet. This spreadsheet was developed in Microsoft® Excel 2002 and may not work on other programs or on older versions of Excel.

NOTE: The spreadsheet below has been updated to make it consistent with the updated Risk-Based Decision Making for the Remediation of Petroleum Contaminated Sites. It now also accepts data in feet and cubic yards as well as meters and cubic meters.

HOT Screening Model Spreadsheet