Division of Spill Prevention and Response


The Cleanup Process

Instructions are found in the Alaska Administrative Code of regulations, Title 18, Chapter 75, Articles 3 and 9.

The process shown on this page is typically used for situations in which contamination has gone underground, polluting soil or even groundwater. The cleanup process can range from a complex, formal cleanup with extensive public involvement and lasting several years to a simple one taking only a few months. Much depends on the source and extent of contamination and the threat to humans and the environment. This page is designed to be used by persons who are responsible by law for site cleanup and those qualified to perform cleanup work.

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Table of Contents


Notification of Liability for Cost Recovery

Initial Response

Work plan


Cleanup Plan

Final Report

Downloadable Copy of 18 AAC 75
Cleanup Process for Contaminated Sites
Program Flowchart












Note: Most Department of Defense sites in Alaska follow the process outlined in the federal law CERCLA. The steps have different names but the process is similar. (Learn more about the CERCLA process.)


Information on toxicology, hazardous chemicals, and environmental health at TOXNET

Preliminary Steps


The person in charge of the operation or facility notifies DEC when a discharge, spill, release or contamination is discovered.


Associated Regulations: 18AAC 75.300, see 18 AAC 75, Article 3 (PDF 683K), updated June 17, 2015


Notification of Liability for Cost Recovery:

DEC will issue the responsible person  notification of their liability for cleaning up the contamination, and also for costs incurred by the state. Alaska Statutes 46.08.070 (Reimbursement for Containment and Cleanup) require that recovery be sought for certain costs, including oversight activities, incurred by the State in responding to pollution incidents.  Billable oversight expenditures include the direct cost of staff time plus indirect state overhead costs. Billable staff time includes all time spent on activities related to the incident, including site visits, response and report reviews, correspondence, telephone conversations, meetings, and legal services.


Initial Response:

The responsible person must respond to the spill: contain, investigate, and clean up contamination under DEC oversight.


DEC will require additional cleanup when soil and groundwater contamination remains after the source of contamination has been abated, or when a release of a hazardous substance was caused by past activities.


Associated Regulations: 18AAC 75.310, 18AAC 75.315, see 18 AAC 75, Article 3 (PDF 683K), updated June 17, 2015.

Emergency or Interim Removal Action

With DEC approval, the responsible person or DEC may take action to contain contamination or remove its source, or take measures to reduce risk. This step may happen at any time in the process and may or may not result in site closure.


Associated Regulations: 18AAC 75.330, see 18 AAC 75, Article 3 (PDF 683K), updated June 17, 2015.


Site Characterization

Field Sampling Guidance For Contaminated Sites and Leaking Underground Storage Tank Sites

Site characterization is often an iterative process. Planning, investigating, and reporting may occur more than once. Work with your DEC project manager to determine how formal the work plan and report should be for your site characterization effort.


The guidance document listed at right is currently the best statement of the overall procedures used during investigation of a contaminated site. Although they lack information on non-petroleum contaminants, they are useful to all cleanup efforts. (You will find that these documents contain many similarities. DEC plans to combine these guidances in the future.)


Work Plan

The responsible person has a qualified environmental professional (typically a contractor) prepare a site characterization work plan for DEC approval. The intent of a work plan is to identify the source and the extent of contamination and evaluate the threat to human health and the environment. See 18 AAC 75, Article 3, and scroll to section 335(b) for a full list of work plan requirements.

Planning for site characterization involves the following steps:

1) Scoping

Responsible person and qualified environmental professional meet with DEC to discuss what is known about the site and set data quality objectives. Before the meeting, complete the Human Health Scoping Form and review the Ecological Scoping Guidance.

Human Health Scoping Form
Ecological Scoping Guidance














2) Conceptual Site Model

Following the Conceptual Site Model Guidance, the qualified environmental professional prepares a Conceptual Site Model, which may be either a separate report or included with a work plan. This is a first estimate of what and where the contaminants are, how they behave under site conditions, and what threat they may pose. Revisions to the Conceptual Site Model are made as more information is discovered.


Conceptual Site Model Guidance














3) Work plan Submittal

Work plans must be approved by DEC and must include some discussion of the following:

For help in determining the contaminants of concern for the investigation, see the Cumulative Risk Guidance.

For regulated Underground Storage Tanks, a work plan should be prepared in accordance with the Underground Storage Tanks Procedures Manual.  For other sites, work plans should be prepared in accordance with the Draft Field Sampling Guidance and the Site Characterization Work Plan and Reporting Guidance for Investigation of Contaminated Sites document.


Underground Storage Tanks Procedures Manual
Cumulative Risk Guidance
Site Characterization Work Plan and Reporting Guidance for Investigation of Contaminated Sites

4) Field Effort

Guided by the work plan, the qualified environmental professional collects samples and gathers more information at the site; DEC oversees this work. Field sampling may include soil, water, air, sediment, and waste.



Site characterization reports are submitted for DEC review after completion of the field effort and receipt of analytical results from a qualified laboratory. See 18 AAC 75, Article 3, and scroll to section 335(c) for a list of requirements.


Reporting must include the following elements:

5) Data Quality Assessment

The qualified environmental professional evaluates the quality of the data collected during the field effort and ensures that the data interpretation is accurate. The requirements of the Laboratory Data and Quality Assurance Technical Memorandum must be met, and the Laboratory Data Review Checklist must be completed and submitted with the report.

Laboratory Data and Quality Assurance Technical Memorandum
Laboratory Data Review Checklist














6) Exposure Pathway Analysis

Using the analytical data and other information collected during the field effort, the qualified environmental professional evaluates each exposure pathway identified in the Conceptual Site Model. Before site closure, the qualified environmental professional must calculate the cumulative risk to humans from all exposure pathways as described in the Cumulative Risk Guidance. For some pathways, a qualitative evaluation may be enough to either determine that further investigation or cleanup is needed or that the contamination is limited enough that no significant exposure is expected. Consult with the DEC project manager regarding the extent of evaluation required for each pathway.

A human health or ecological risk assessment is sometimes conducted to evaluate potential effects from the contamination and to develop cleanup levels. A human health risk assessment looks at the risks to humans from contamination at the site, and an ecological risk assessment looks at the risks to plants and animals. The qualified environmental professional should consult the Risk Assessment Procedures Manual when doing either type of risk assessment.

Risk Assessment Procedures Manual Updated October 2015













7) Cleanup Levels

Soil cleanup levels can be determined by of one of the following four methods:

Associated Regulations: 18AAC 75.340, See 18 AAC 75, Article 3 (PDF 683K), updated June 17, 2015.

Methods Two and Three are described in the Cleanup Level Guidance and Method Four in the above Risk Assessment Procedures Manual. The qualified environmental professional recommends a level based on the contaminant and the pathways of exposure by which humans or the environment might be harmed. When using Method Two, Three, or Four, cleanup levels may need to be adjusted to account for cumulative risk effects.














For printable tables for Methods One and Two, please see 18 AAC 75, Article 3, and scroll to Section 341.


Groundwater cleanup levels are based on drinking water standards.  To determine groundwater cleanup levels, use Table C in 18 AAC 75.345.

(For a printable version, please see 18 AAC 75, Article 3 and scroll to Section 345.) The qualified environmental professional may demonstrate that groundwater is not a source of drinking water in accordance with 18 AAC 75.350.


Other media

Associated Regulations: 18AAC 70 Water Quality Standards

Vapor Intrusion Technical Memorandum














8) Report Preparation and Submittal

Site characterization reports are prepared by a qualified environmental professional on behalf of the responsible party and submitted to DEC for approval. See 18 AAC 75, Article 3, and scroll to Section 335(c) for information on requirements. Each report includes:

The final site characterization report should also include:

A risk assessment report may serve as the final site characterization report at a site.

DEC's Cleanup Decision


DEC will approve the final site characterization or risk assessment report if it determines that the work described in the report and the cleanup techniques proposed are protective of human health and the environment. The department may modify proposed cleanup techniques or require additional cleanup steps. DEC will consider public input.


In a cleanup following the federal CERCLA process, the decision involves first issuing a "Proposed Plan," inviting public comment, and writing a final "Record of Decision."


Associated Regulations: 18AAC 75.335(d), see 18 AAC 75, Article 3 (PDF 683K), updated June 17, 2015.


The cleanup process varies greatly in level of detail. The documentation for simple cleanups may be a few pages containing abbreviated descriptions. For complex cleanups, substantial, detailed documentation may be required to fully explain more complex plans and technologies.


Chapter One of the Underground Storage Tanks Procedures Manual provides our best guidance for cleanup and recharacterization of a site and may also be helpful for other contaminant types.


Cleanup Plan

The cleanup plan is the first part of the cleanup phase and presents the technical specifications for the cleanup action. Once DEC approves the plan, the responsible person implements the cleanup action. Cleanup plans may also be amended if the cleanup action proves to be insufficient. A cleanup plan includes these steps:

9) Cleanup Schedule Submittal

Before work begins, the responsible person submits a schedule for conducting field work, monitoring, cleanup, and submittal of interim and final cleanup reports for DEC approval. Additional approval will be needed if the process is modified.


10) Cleanup Plan Submittal

The responsible person has a qualified environmental professional (typically a contractor) prepare a cleanup plan for DEC approval. The cleanup plan includes these elements:

In addition, a sampling and analysis plan for confirmatory sampling, waste management plan, site control plan, site monitoring plan, or other requirements may be necessary. See the regulatory links below for more specifics on sampling and analysis, cleanup operation requirements, offsite or portable treatment facilities, soil storage and disposal, and land use and activity controls.


For regulated Underground Storage Tanks, the cleanup plan should be prepared in accordance with the Underground Storage Tanks Procedures Manual.  Remediation guidance for other compounds or for more specific topics can be found in on CS guidance and forms page under the Remediation Operations section.


11) Field Effort

The responsible person ensures that the work is conducted or supervised by a qualified environmental professional, guided by the work plan, and that sampling and analysis are conducted by a qualified impartial third party. DEC monitors progress toward the objectives, schedules, and reporting requirements set out in the cleanup plan. The level of oversight will depend on the complexity of the site and the cleanup action, the hazards posed by the site, and the degree of public interest, along with other considerations.

Final Report

12) Report Preparation and Submittal

The responsible person submits interim cleanup reports, as necessary, to DEC. These reports are prepared by a qualified environmental professional and describe cleanup actions, remedial system operation and maintenance, monitoring, and any confirmatory sampling or recharacterization of the site. Steps 5 and 6 above should be updated in the report when any recharacterization occurs.


When cleanup is complete, a final cleanup report and closure request must be submitted to DEC for review. See 18 AAC 75, Article 3 and scroll to Section 380 for regulations on final reporting requirements. This report should include the following:

DEC's Closure Decision


DEC will consider cleanup of a contaminated site complete when efforts to reduce hazardous substance contamination have either achieved levels whereby they no longer pose a potential unacceptable risk to human health, safety or welfare, or to the environment. There are two categories of cleanup complete determinations. Sites that meet unrestricted residential land use levels and do not pose a potential ecological risk are closed with a "Cleanup Complete" status. Sites with residual contaminants that warrant a limitation on future use are granted a "Cleanup Complete with Intuitional Controls" status. DEC recovers the cost of its oversight or damages from the responsible person. The landowner gets official notice of the closure. See 18 AAC 75, Article 3 and scroll to Section 380 for regulation information on site closure.

Cleanup Complete – Institutional Controls
If DEC requires the responsible person to maintain land use and/or activity controls to protect human health and the environment from future exposure, the department would then grant a "Cleanup Complete – Institutional Controls." (see "institutional controls.")


Note: If you are a responsible party that is required to periodically report to DEC, you may submit documents electronically to dec.icunit@alaska.gov.


For more information see closure of a contaminated site.

For follow-up questions, please contact the Contaminated Sites Program office closest to you:

Juneau:   907-465-5390                
Anchorage:   907-269-7503                
Kenai:   907-262-5210, ext. 231
Fairbanks:   907-451-2143