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
Downloadable copy of 18 AAC 75,
Article 3
(PDF 314K)
Preliminary Steps
Notification and Initial Response

Simplified versions of the cleanup process:

  • Cleanup process for contaminated sites (PDF 304K)
  • Program flowchart (PDF 87K)

At Any Time
Emergency or Interim Removal Action

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.)

DEC's Cleanup Decision
Cleanup Plan Information on toxicology, hazardous chemicals, and environmental health at TOXNET
Final Report
DEC's Closure Decision

Associated regulations and guidance

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

18AAC 75.300

See 18 AAC 75, Article 3 (PDF 314K),
eff. 4/8/12


*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.

18AAC 75.310
18AAC 75.315


At any time
*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.

18AAC 75.330

Site Characterization

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 workplan 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.)

Underground Storage Tanks Procedures Manual


The responsible person has a qualified person (typically a contractor) prepare a site characterization workplan for DEC approval. The intent of a workplan is to identify the source and the extent of contamination and evaluate the threat to human health and the environment. See link to regulations at right for a full list of workplan requirements.

Planning for site characterization involves the following steps:

18AAC 75.335(b)

See 18 AAC 75, Article 3 (PDF 314K),
eff. 4/8/12


Responsible person and qualified person 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

2Conceptual Site Model
Following the Conceptual Site Model Guidance, the qualified person prepares a Conceptual Site Model, which may be either a separate report or included with a workplan. 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
3Workplan Submittal
Workplans must be approved by DEC and must include some discussion of the following:
  • Summary of existing information
  • Sampling approach (to gather reliable data to identify the source, contaminants of concern, the extent of contamination, and the threat to human health and the environment)
  • Identity and qualifications of key participants
  • Quality assurance and quality control procedures

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

For petroleum spills, a workplan should be prepared in accordance with the Underground Storage Tanks Procedures Manual. Guidance for other compounds or for specific characterization topics can be found in the Site Characterization and Cleanup link to the right.

Underground Storage Tanks Procedures Manual

Screening Procedures


Site Characterization and Cleanup

4Field Effort
Guided by the workplan, the qualified person 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 the link to regulations at right for a list of requirements.

Reporting must include the following elements:

5Data Quality Assessment
The qualified person 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.

18AAC 75.335(c)

Laboratory Data and Quality Assurance Policy--Tech Memo


6Exposure Pathway Analysis
Using the analytical data and other information collected during the field effort, the qualified person evaluates each exposure pathway identified in the Conceptual Site Model. Before site closure, the qualified person 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 person should consult the Risk Assessment Procedures Manual when doing either type of risk assessment.



Cumulative Risk Guidance

Risk Assessment Procedures Manual


7Cleanup Levels

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

  • Method One provides original cleanup levels based on a decision matrix
  • Method Two provides pre-calculated risk-based cleanup levels
  • Method Three levels are calculated using site-specific information
  • Method Four levels are calculated on the basis of a risk assessment

The regulatory link to the right describes each of these.

Methods Two and Three are described in the Cleanup Level Guidance and Method Four in the Risk Assessment Procedures Manual. The links at the right will take you to these documents as well as other useful information. The qualified person 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, click the link at the right to 18 AAC 75, Article 3, and scroll to Section 341.



See 18 AAC 75, Article 3 (PDF 314K),
eff. 4/8/12

18AAC 75.340

Cleanup Level Guidance

Risk Assessment Procedures Manual

Download 18 AAC 75 Article 3 (PDF 314K)

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, click the link at the right and scroll to Section 345.) The qualified person may demonstrate that groundwater is not a source of drinking water in accordance with 18 AAC 75.350.

Download 18 AAC 75 Article 3 (PDF 314K)

18AAC 75.350

Other media Sediment - no levels have been set in regulation for sediments, but screening levels are available in the Ecoscoping Guidance. Levels are approved by DEC on a site specific basis.

Ecological Scoping Guidance

Surface water - must meet the state's Water Quality Standards.

18AAC 70 Water Quality Standards

Indoor air - See DEC's Vapor Intrusion Technical Memorandum Guidance
Vapor intrusion

8 Report Preparation and Submittal
Site characterization reports are prepared by a qualified person on behalf of the responsible party and submitted to DEC for approval. See link to regulations at right for information on requirements. Each report includes:

  • Site background, including physical setting and historical information;
  • A description of the revised Conceptual Site Model;
  • Methods used for the characterization, including any field adjustments to the site characterization workplan; and
  • Sampling analysis, analytical results data deliverables, and a completed Laboratory Data Review Checklist (see Step 5).

The final site characterization report should also include:

  • Conclusions concerning the nature and extent of contamination;
  • Conclusions concerning the human and environmental hazards posed. A formal risk assessment, if conducted, must also be reported;
  • Calculation of cleanup levels using the applicable method(s);
  • Analysis of cleanup alternatives and recommendation of cleanup technique(s) to be used at the site. Cleanup techniques are recommended based on their protectiveness, practicality, effectiveness, conformity with state regulations, and consideration of any public comment; and
  • Recommendations on land use and activity (also called " institutional") controls that would allow reuse of the land while protecting human health and the environment

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



18AAC 75.335(c)

Download 18 AAC 75 Article 3 (PDF 314K)

Laboratory Data Review Checklist

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."

18AAC 75.335(d)

Download 18 AAC 75 Article 3 (PDF 314K)

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.

Underground Storage Tanks Procedures Manual

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:

9Cleanup 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 person (typically a contractor) prepare a cleanup plan for DEC approval. The cleanup plan includes these elements:

  • Specifications of the proposed cleanup technique
  • Provisions for minimizing contaminant migration to previously unaffected areas
  • Provisions for disposal of contaminated soil and groundwater

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 at right 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 petroleum spills, 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 the Remediation Operations link to the right.

11Field Effort
The responsible person ensures that the work is conducted or supervised by a qualified person, guided by the workplan, 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.

Download 18 AAC 75 Article 3 (PDF 314K)

18AAC 75.355 - Sampling and analysis)
18AAC 75.360 (4) - Elements of a cleanup plan)
18AAC 75.365 - Offsite or portable treatment facilities
18AAC 75.370 - Soil storage and disposal
18AAC 75.375 - Institutional controls.

Underground Storage Tanks Procedures Manual

Remediation Operations

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 person 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 link to regulations at right for information on final reporting requirements. This report should include the following:

  • Information about the release, name of any responsible parties, and name of current owners and operators at the site;
  • A description of any environmental damage;
  • A free product report that summarizes the presence and disposition of free product;
  • A description of cleanup activities, including required permits, and confirmation that hazardous waste was handled in accordance with the federal law RCRA.
  • A description of the ultimate fate of any contaminated materials removed from the site for cleanup
  • Locations, concentrations, and amounts of contaminated materials left in place;
  • Field screening and laboratory analytical results; and
  • A description of any significant exposure pathways that remain at the site and a demonstration of compliance with applicable institutional controls.

18AAC 75.380

Download 18 AAC 75 Article 3 (PDF 314K)

DEC's Closure Decision

DEC may consider cleanup of a contaminated site complete when efforts to reduce hazardous substance contamination have either achieved the strictest levels established in state regulation, or the possibility of human exposure to any residual contamination is highly unlikely. DEC will then give the site “Cleanup Complete” status. DEC will close the site, and any legal proceedings are closed. DEC recovers the cost of its oversight or damages from the responsible person. The landowner gets official notice of the closure. See link to regulations at right for 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.

18AAC 75.380

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:   907-451-2153