The 1988 UST File: When an HREC Is Not Actually Closed
You are reviewing a Phase I for a 2-acre former gas station. The file contains a 1994 state letter stating that a 10,000-gallon gasoline UST was removed and 'no further action is required.' The letter references soil sampling only; groundwater was never sampled. The property is now a vacant lot. A neighboring property has a municipal well field 600 feet downgradient. The current owner provides the 1994 letter and asks you to classify the tank as an HREC so the file can close. Soil logs from 1994 show benzene at 40 mg/kg at 6 feet, and the water table is at 12 feet.
1. Can the 1994 letter support an HREC classification? Explain the conditions an HREC must satisfy.
Read the worked answer
No. The letter does not satisfy the HREC definition.
An HREC requires that the past release has been addressed to the satisfaction of the applicable regulatory authority and that hazardous substances do not remain at the property at concentrations exceeding unrestricted use criteria (or, for a property with restrictions, the applicable restricted criteria).
Two failures here:
- Scope gap. The closure addressed soil only. Groundwater was never sampled, and the water table is only 6 feet below the deepest sampled interval. A closure letter limited to one medium does not close the release.
- Residual exceedance. Benzene at 40 mg/kg at 6 feet is far above typical unrestricted-use soil screening levels, and the depth places it close to the capillary fringe. The material has not been shown to be absent above criteria.
The correct classification is a REC, with a recommendation for groundwater and soil gas investigation. The 1994 letter is a regulatory document to be summarized, not a free pass.
2. The current owner argues that because the state issued a closure letter, the lender is protected. How would you respond, and what does the Phase I report need to say?
Read the worked answer
A closure letter is evidence, not immunity. It closes the state's file on the facts then presented; it does not bind a future purchaser, a federal agency, or a private party, and it does not erase residual contamination.
The report should:
- Summarize the 1994 letter accurately, including its scope limitation (soil only).
- Note that groundwater was not evaluated and that the water table is shallow.
- Identify the downgradient municipal well field as a sensitive receptor and migration pathway concern.
- Classify the tank release as a REC and recommend a Phase II with groundwater monitoring wells and soil gas sampling.
Do not describe the letter as 'no further action' without qualification. The phrase invites the reader to assume a closure that did not occur.