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Implementation Memorandum No. 18: Petroleum Vapor Intrusion (VI): Updated Screening Levels, Cleanup Levels, and Assessing PVI Threats to Future Buildings (Historical)

Publication number Date Published Date Revised
17-09-043August 2017January 2018
VIEW NOW This publication is historical. It is unavailable on our website. To request a copy, please use the contact listed below.
Author(s) Mark Gordon, P.E., Policy & Technical Support Unit, Toxics Cleanup Program
Description This memorandum provides petroleum vapor intrusion (PVI) guidance from the Washington State Department of Ecology.

This memo supplements the information in Implementation Memo No. 14 (publication no. 16-09-046). It also: 1) Provides the basis for several modifications to the CLARC data tables to account for the additive effects of non-carcinogenic compounds present in petroleum mixtures. This includes establishing a generic TPH cleanup level of 140 µg/m3 as well as corresponding sub-slab and deep soil gas screening levels. 2) Explains how to assess whether PVI represents a reasonably likely threat to future buildings. 3) Provides additional direction for developing Tier I or Tier II PVI sampling plans.

This memo primarily applies to releases of petroleum-containing fuels from:
1) underground storage tanks, 2) spills, 3) home heating oil tanks, and 4) bulk tank farms. This memo should be used when sites do not initially “screen out” using the process established in Implementation Memo No. 14, or when further vapor evaluation is necessary after implementing the selected cleanup action.

A note about this revision: This implementation memo was originally published as a draft in August 2017 and a revised draft in November 2017. It was finalized in January 2018 based on comments received during a public comment period from August 7 through September 22, 2017.
NOTES This publication has been replaced by a new publication. In March 2022, this document was incorporated into “Guidance for Evaluating Vapor Intrusion in Washington State: Investigation and Remedial Action,” which is available at
The mission of the Department of Ecology is to protect, preserve, and enhance Washington’s environment. To help us meet that goal, please consider the environment before you print or request a copy.

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Keywords Total petroleum hydrocarbons (TPH), Air cleanup levels, Petroleum vapor intrusion (PVI), Groundwater cleanup levels, Soil gas screening levels, Groundwater vapor intrusion screening levels, Model Toxics Control Act (MTCA)
WEB PAGE Vapor Intrusion

Guidance for Evaluating Vapor Intrusion in Washington State: Investigation and Remedial Action

Implementation Memorandum No. 22: Vapor Intrusion (VI) Investigations and Short-Term Trichloroethene (TCE) Toxicity

Implementation Memorandum No. 21: Frequently Asked Questions (FAQs) Regarding Vapor Intrusion (VI) and Ecology's 2009 Draft VI Guidance

Guidance for Remediation of Petroleum Contaminated Sites

Implementation Memorandum No. 14: Updated Process for Initially Assessing the Potential for Petroleum Vapor Intrusion

Model Toxics Control Act Regulation and Statute: MTCA Cleanup Regulation Chapter 173-340 WAC, Model Toxics Control Act Chapter 70.105D RCW, Uniform Environmental Covenants Act Chapter 64.70 RCW