Geologic Sequestration 

of Carbon Dioxide

Underground Injection 

Control (UIC) Program 

Class VI Well Project Plan 

Development Guidance

August 2012
 

Office of Water (4606M) 

EPA 816-R-11-017 

August 2012 

http://water.epa.gov/drink
UIC Program Class VI Well Project Plan ii August 2012

Development Guidance 

Disclaimer 

The Federal Requirements Under the Underground Injection Control Program for Carbon 

Dioxide Geologic Sequestration Wells (75 FR 77230, December 10, 2010), known as the Class

VI Rule, establishes a new class of injection well (Class VI). 

The Safe Drinking Water Act (SDWA) provisions and EPA regulations cited in this document 

contain legally-binding requirements. In several chapters this guidance document makes 

suggestions and offers alternatives that go beyond the minimum requirements indicated by the 

Class VI Rule. This is done to provide information and suggestions that may be helpful for 

implementation efforts. Such suggestions are prefaced by “may” or “should” and are to be 

considered advisory. They are not required elements of the Rule. Therefore, this document does 

not substitute for those provisions or regulations, nor is it a regulation itself, so it does not 

impose legally-binding requirements on EPA, states, or the regulated community. The 

recommendations herein may not be applicable to each and every situation. 

EPA and state decision makers retain the discretion to adopt approaches on a case-by-case basis 

that differ from this guidance where appropriate. Any decisions regarding a particular facility 

will be made based on the applicable statutes and regulations. Mention of trade names or 

commercial products does not constitute endorsement or recommendation for use. EPA is taking 

an adaptive rulemaking approach to regulating Class VI injection wells, and the Agency will 

continue to evaluate ongoing research and demonstration projects and gather other relevant 

information as needed to refine the Rule. Consequently, this guidance may change in the future 

without public notice. 

While EPA has made every effort to ensure the accuracy of the discussion in this document, the 

obligations of the regulated community are determined by statutes, regulations or other legally 

binding requirements. In the event of a conflict between the discussion in this document and any 

statute or regulation, this document would not be controlling. 

Note that this document only addresses issues covered by EPA’s authorities under the SDWA. 

Other EPA authorities, such as Clean Air Act (CAA) requirements to report carbon dioxide 

injection activities under the Greenhouse Gas Mandatory Reporting Rule (GHG MRR) are not 

within the scope of this document. 
UIC Program Class VI Well Project Plan iii August 2012

Development Guidance 

Executive Summary 

The United States Environmental Protection Agency’s (EPA’s) Federal Requirements Under the 

Underground Injection Control (UIC) Program for Carbon Dioxide Geologic Sequestration 

Wells, codified in the U.S. Code of Federal Regulations [40 CFR 146.81 et seq.], referred to as

the Class VI Rule, establishes a new class of injection well (Class VI) and sets minimum federal

technical criteria for Class VI injection wells for the purpose of protecting underground sources 

of drinking water (USDWs). This document is part of a series of technical guidance documents 

that EPA is developing to support owners or operators of Class VI wells and permitting 

authorities. The final Class VI Rule and associated guidance documents are available at

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm. 

The Class VI Rule requires owners or operators of Class VI wells to develop, gain approval for, 

and implement five (5) project-specific plans, including: an Area of Review (AoR) and 

Corrective Action Plan, a Testing and Monitoring Plan, an Injection Well Plugging Plan, a PostInjection Site Care (PISC) and Site Closure Plan, and an Emergency and Remedial Response 

Plan. 

This guidance describes, for Class VI injection well owners or operators, the required elements 

of each plan and the site-specific elements of each GS project that may be considered when 

developing the plans. This document also describes the process by which the UIC Program 

Director will evaluate and approve each plan and how EPA recommends that the plans be 

reviewed and amended, if necessary, throughout the lifecycle of the project. 
UIC Program Class VI Well Project Plan iv August 2012

Development Guidance 

Table of Contents

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Executive Summary ....................................................................................................................................

Table of Contents ........................................................................................................................................

List of Tables ..............................................................................................................................................

List of Exhibits ............................................................................................................................................

List of Appendices ......................................................................................................................................

Acronyms and Abbreviations .................................................................................................................... 

Definitions...................................................................................................................................................

1.0 Introduction ....................................................................................................................................

1.1 Overview and Need for GS Project Plans ......................................................................................

1.2 Interaction of GS Project Plans ......................................................................................................

1.3 Other Relevant Guidance ...............................................................................................................

1.4 Organization of this Document ......................................................................................................

2.0 Area of Review and Corrective Action Plan ..................................................................................

2.1 Developing the AoR and Corrective Action Plan ..........................................................................

2.1.1 The method for delineating the AoR ...................................................................................

2.1.2 The minimum fixed frequency to reevaluate the AoR ........................................................

2.1.3 Conditions that would warrant an early AoR reevaluation .................................................

2.1.4 How monitoring and operational data will inform AoR reevaluations ...............................

2.1.5 How corrective action will be conducted ............................................................................

2.2 UIC Program Director’s Evaluation of the AoR and Corrective Action Plan ...............................

2.3 Amending the AoR and Corrective Action Plan ............................................................................

3.0 Testing and Monitoring Plan .........................................................................................................

3.1 Developing the Testing and Monitoring Plan ................................................................................

3.1.1 Analysis of the carbon dioxide stream ................................................................................

3.1.2 Installation and use of continuous recording devices..........................................................

3.1.3 Corrosion monitoring ..........................................................................................................

3.1.4 Ground water quality monitoring ........................................................................................

3.1.5 A demonstration of external mechanical integrity ..............................................................

3.1.6 A pressure fall-off test .........................................................................................................

3.1.7 Carbon dioxide plume and pressure front tracking .............................................................

3.1.8 Surface air and/or soil gas monitoring (if required) ............................................................

3.1.9 Any additional monitoring required by the UIC Program Director ....................................

3.2 UIC Program Director’s Evaluation of the Testing and Monitoring Plan .....................................

3.3 Amending the Testing and Monitoring Plan ..................................................................................

4.0 Injection Well Plugging Plan .........................................................................................................

4.1 Developing the Injection Well Plugging Plan................................................................................

4.2 UIC Program Director’s Evaluation of the Injection Well Plugging Plan .....................................

4.3 Amending the Injection Well Plugging Plan .................................................................................

5.0 Post-Injection Site Care (PISC) and Site Closure Plan ..................................................................

5.1 Developing the Post-Injection Site Care and Site Closure Plan ....................................................

5.1.1 Pre-injection and predicted post-injection pressure differentials in the injection zone ......

5.1.2 Predicted position of the carbon dioxide plume and pressure front at site closure .............

5.1.3 Monitoring location, methods, and proposed frequency .....................................................

5.1.4 Schedule for submitting post-injection site care monitoring results ...................................

5.1.5 Demonstration of an alternative post-injection site care timeframe....................................

5.1.6 Information that will Support the Non-Endangerment Demonstration .............................

5.1.7 Site Closure Plan .................................................................................................................
UIC Program Class VI Well Project Plan v August 2012

Development Guidance 

5.2 UIC Program Director’s Evaluation of the Post-Injection Site Care and Site Closure Plan .......... 48

5.3 Amending the Post-Injection Site Care and Site Closure Plan ...................................................... 49

6.0 Emergency and Remedial Response Plan ...................................................................................... 51

6.1 Developing the Emergency and Remedial Response Plan ............................................................ 52

6.2 UIC Program Director’s Evaluation of the Emergency and Remedial Response Plan .................. 55

6.3 Amending the Emergency and Remedial Response Plan .............................................................. 56
UIC Program Class VI Well Project Plan vi August 2012

Development Guidance 

List of Tables

Table 1: Examples of Interaction of GS Project Plans ................................................................... 7

List of Exhibits 

Exhibit 1: Process for Developing, Approving, and Amending GS Project Plans......................... 3

Exhibit 2: Draft UIC Program Class VI Well AoR Evaluation and Corrective Action Guidance 

Highlights .................................................................................................................... 11

Exhibit 3: Draft UIC Program Class VI Well Testing and Monitoring Guidance Highlights ...... 25

Exhibit 4: Draft UIC Program Class VI Well Plugging, PISC, and Site Closure Guidance 

Highlights..................................................................................................................... 40
UIC Program Class VI Well Project Plan vii August 2012

Development Guidance

List of Appendices

Appendix A: Sample Template of an Area of Review and Corrective Action Plan

Appendix B: Sample Template of a Testing and Monitoring Plan

Appendix C: Sample Template of an Injection Well Plugging Plan

Appendix D: Sample Template of a PISC and Site Closure Plan 

Appendix E: Sample Template of an Emergency and Remedial Response Plan

Appendix F: Checklist of Recommended Considerations for Evaluating Plans and Amendments
UIC Program Class VI Well Project Plan viii August 2012

Development Guidance 

Acronyms and Abbreviations

AoR Area of Review

CFR Code of Federal Regulations 

GS Geologic Sequestration 

MIT Mechanical Integrity Test

PISC Post-injection Site Care 

pH Potential for Hydrogen Ion Concentration 

SC Specific Conductivity 

SDWA Safe Drinking Water Act

TDS Total Dissolved Solids 

UIC Underground Injection Control 

USDW Underground Source of Drinking Water

VOC Volatile Organic Compound 
UIC Program Class VI Well Project Plan ix August 2012

Development Guidance 

Definitions 

Key to definition sources: 

1: This definition was drafted for the purposes of this document. 

2: 40 CFR 146.81(d). 

3: 40 CFR 144.6(f) and 144.80(f). 

4: Class VI Rule preamble.

5: EPA’s UIC website (http://water.epa.gov/type/groundwater/uic/glossary.cfm).

Analyte means a chemical species that is the subject of analysis for determination of 

concentration.1 

Area of Review means the region surrounding the geologic sequestration project where USDWs 

may be endangered by the injection activity. The area of review is delineated using 

computational modeling that accounts for the physical and chemical properties of all phases of 

the injected carbon dioxide stream and displaced fluids, and is based on available site 

characterization, monitoring, and operational data as set forth in 40 CFR 146.84.2 

Carbon dioxide plume means the extent underground, in three dimensions, of an injected 

carbon dioxide stream.2

Carbon dioxide stream means carbon dioxide that has been captured from an emission source 

(e.g., a power plant), plus incidental associated substances derived from the source materials and 

the capture process, and any substances added to the stream to enable or improve the injection 

process. This does not apply to any carbon dioxide stream that meets the definition of a 

hazardous waste under 40 CFR Part 261.2

Class VI wells means wells that are not experimental in nature that are used for geologic 

sequestration of carbon dioxide beneath the lowermost formation containing a USDW; or, wells 

used for geologic sequestration of carbon dioxide that have been granted a waiver of the 

injection depth requirements pursuant to requirements at 40 CFR 146.95; or, wells used for 

geologic sequestration of carbon dioxide that have received an expansion to the areal extent of an 

existing Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to 

40 CFR 146.4 and 144.7(d).3 

Confining zone means a geologic formation, group of formations, or part of a formation 

stratigraphically overlying the injection zone(s) that acts as a barrier to fluid movement. For 

Class VI wells operating under an injection depth waiver, confining zone means a geologic 

formation, group of formations, or part of a formation stratigraphically overlying and underlying 

the injection zone.2 

Corrective action means the use of Director-approved methods to ensure that wells within the 

area of review do not serve as conduits for the movement of fluids into underground sources of 

drinking water.2
UIC Program Class VI Well Project Plan x August 2012

Development Guidance 

Geologic sequestration means the long-term containment of a gaseous, liquid, or supercritical 

carbon dioxide stream in subsurface geologic formations. This term does not apply to carbon 

dioxide capture or transport.2

Geologic sequestration project means an injection well or wells used to emplace a carbon 

dioxide stream beneath the lowermost formation containing a USDW; or, wells used for geologic 

sequestration of carbon dioxide that have been granted a waiver of the injection depth 

requirements pursuant to requirements at 40 CFR 146.95; or, wells used for geologic 

sequestration of carbon dioxide that have received an expansion to the areal extent of an existing 

Class II enhanced oil recovery or enhanced gas recovery aquifer exemption pursuant to 40 CFR 

146.4 and 144.7(d). It includes the subsurface three-dimensional extent of the carbon dioxide 

plume, associated area of elevated pressure, and displaced fluids, as well as the surface area 

above that delineated region.2 

Injection depth waivers refer to the provisions at 40 CFR 146.95 that allow owners or operators 

to seek a waiver from the Class VI injection depth requirements for GS to allow injection into 

non-USDW formations while ensuring that USDWs are protected from endangerment.1 

Mechanical integrity means the absence of significant leakage within the injection tubing, 

casing, or packer (known as internal mechanical integrity), or outside of the casing (known as 

external mechanical integrity).4 

Mechanical integrity test refers to a test performed on a well to confirm that a well maintains 

internal and external mechanical integrity. MITs are a means of measuring the adequacy of the 

construction of an injection well and a way to detect problems within the well system.4

Multiphase flow parameters refer to model parameters that describe the rate of fluid flow and 

fluid saturation for multiple immiscible fluids within a porous medium.1 

Phased corrective action refers to a provision of the Class VI Rule [40 CFR 146.84(b)(2)(iv)]

afforded to Class VI well owners or operators to defer some corrective action needed within the 

AoR, but farther away from the injection well, until after injection has commenced, but prior to 

carbon dioxide plume and pressure front movement into that particular area.1

Post-injection site care means appropriate monitoring and other actions (including corrective 

action) needed following cessation of injection to ensure that USDWs are not endangered, as 

required under 40 CFR146.93.2

Pressure front means the zone of elevated pressure that is created by the injection of carbon 

dioxide into the subsurface. For [GS projects], the pressure front of a carbon dioxide plume 

refers to a zone where there is a pressure differential sufficient to cause the movement of injected 

fluids or formation fluids into a USDW.2 

Site closure means the point/time, as determined by the Director following the requirements 

under 40 CFR 146.93, at which the owner or operator of a geologic sequestration site is released 

from post-injection site care responsibilities.2 
UIC Program Class VI Well Project Plan xi August 2012

Development Guidance

Stochastic estimate means a type of modeling prediction that is based on a statistically 

generated representation of key model input parameters.1

Underground Injection Control Program refers to the program EPA, or an approved state, is 

authorized to implement under the Safe Drinking Water Act (SDWA) that is responsible for 

regulating the underground injection of fluids by wells injection. This includes setting the federal

minimum requirements for construction, operation, permitting, and closure of underground 

injection wells.1

Underground Injection Control Program Director refers to the chief administrative officer of 

any state or tribal agency or EPA Region that has been delegated to operate an approved UIC 

program.5

Underground Source of Drinking Water means an aquifer or portion of an aquifer that 

supplies any public water system or that contains a sufficient quantity of ground water to supply 

a public water system, and currently supplies drinking water for human consumption, or that 

contains fewer than 10,000 mg/L total dissolved solids and is not an exempted aquifer.4
UIC Program Class VI Well Project Plan 1 August 2012

Development Guidance 

1.0 Introduction

Owners or operators of Class VI carbon dioxide injection wells must develop, implement, 

periodically review and, if necessary, amend a series of project- and site-specific plans that guide 

the management of each geologic sequestration (GS) project. The purpose of this Project Plan 

Development Guidance is to present recommendations for Class VI injection well owners or 

operators, in developing the project plans required in the Federal Requirements Under the 

Underground Injection Control (UIC) Program for Carbon Dioxide Geologic Sequestration 

Wells [40 CFR 146.81 et seq.], hereafter referred to as the Class VI Rule. This guidance focuses 

on preparing GS project plans that meet the requirements of the Class VI Rule, submitting them 

to the appropriate UIC Program Director for approval, and periodically reviewing and amending

the plans. 

1.1 Overview and Need for GS Project Plans

Owners or operators of Class VI wells must prepare five (5) project plans and submit them to the 

UIC Program Director for approval with their Class VI permit application. When the plans are 

approved, they become an enforceable part of the Class VI permit. The required project plans, 

which must be based on site-specific information, include the following: 

• Area of Review (AoR) and Corrective Action Plan. This plan describes how an owner or 

operator intends to delineate the AoR for the Class VI injection well and ensure that all 

identified deficient artificial penetrations (i.e., wells that are improperly plugged or 

completed) will be addressed by corrective action techniques so that they will not become 

conduits for fluid movement into underground sources of drinking water (USDWs). 

• Testing and Monitoring Plan. This plan describes how the owner or operator intends to 

perform all necessary testing and monitoring associated with a GS project, including injectate 

monitoring, performing mechanical integrity tests (MITs), corrosion monitoring, tracking the 

carbon dioxide plume and area of elevated pressure, monitoring geochemical changes above 

the confining zone, and, at the discretion of the UIC Program Director, surface air and/or soil 

gas monitoring for carbon dioxide fluctuations and any additional tests necessary to ensure 

USDW protection from endangerment. 

• Injection Well Plugging Plan. This plan describes how, following the cessation of injection, 

the owner or operator intends to plug the Class VI injection well using the appropriate 

materials and methods to ensure that the well will not become a conduit for fluid movement 

into USDWs in the future. 

• Post-Injection Site Care (PISC) and Site Closure Plan. This plan describes how the owner 

or operator intends to monitor the site after injection has ceased, in order to ensure that the 

carbon dioxide plume and pressure front are moving as predicted and USDWs are not 

endangered. PISC monitoring must continue until it can be demonstrated that the site poses 

no further endangerment to USDWs. 

• Emergency and Remedial Response Plan. This plan describes the actions that the owner or 

operator intends to take in the event of movement of the injectate or formation fluids in a 

manner that may cause an endangerment to a USDW, including the appropriate people to 

contact.
UIC Program Class VI Well Project Plan 2 August 2012

Development Guidance 

These detailed, site-specific GS project plans are necessary to ensure that management of the GS 

project is based on the most up-to-date site characterization, modeling, operational, and 

monitoring data to protect USDWs from endangerment. The plans also afford the flexibility 

needed to address the variety of types of geologic formations in which GS will occur, while also 

facilitating dialogue between the Class VI injection well owner or operator and the UIC Program 

Director. 

Class VI well permits are issued for the operating life of the project (i.e., from authorization of 

injection through site closure, which may occur many decades later). Thus, unlike some other 

injection well classes regulated under the UIC Program, there is no periodic reapplication for, or 

reissuance of, a Class VI permit. Instead, these five GS project plans, which are reviewed as part 

of the Class VI permit application review and approval process and incorporated into the Class

VI permit, must be amended periodically, as specified in the Class VI Rule. The iterative process 

of developing and executing the GS project plans described in this guidance is tailored to the 

unique aspects of GS and is intended to ensure that time and resources are committed to the most 

critical aspects of managing Class VI injection well operations (see Exhibit 1). 

The project plans must be submitted with the permit application for each Class VI well. While 

area permits are not an option for permitting of Class VI wells per 40 CFR 144.33(a)(5), owners 

or operators can realize some efficiencies in developing and implementing project plans where 

certain aspects of multiple wells in an area are common. For example, owners or operators may 

develop Testing and Monitoring Plans or PISC and Site Closure Plans that include ground water 

monitoring or carbon dioxide plume and pressure front tracking over an area that would satisfy 

the requirements for several permits simultaneously. Additionally, if several wells in a field have 

similar construction, owners or operators may plan to plug each well in a similar manner; 

however, a separate Injection Well Plugging Plan is required for each well (i.e., tailored to its 

depth and any other unique characteristics of the well). 

In addition to providing permitting efficiency, collectively considering all wells in a field will 

ensure that the site is evaluated and operated in a holistic manner and that all aspects of the 

project that may impact USDWs have been evaluated and addressed. The owner or operator 

should discuss the implications of combining common elements and activities associated with 

multiple wells/permits with the UIC Program Director to ensure that every well is constructed, 

operated, monitored, plugged, and closed in a manner that is protective of USDWs.
UIC Program Class VI Well Project Plan 3 August 2012

Development Guidance 

Exhibit 1: Process for Developing, Approving, and Amending GS Project Plans 
UIC Program Class VI Well Project Plan 4 August 2012

Development Guidance 

1.2 Interaction of GS Project Plans 

Development, approval, and implementation of the project-specific plans involve an iterative 

process. Exhibit 1 presents a general overview of the process of gathering data for, developing, 

approving, and periodically reviewing and amending the plans throughout the life of a GS 

project. Note that this Exhibit is a conceptual overview only and may not capture all of the 

permutations of activities or the order in which they may happen at every GS project. The 

Sections below describe this process in greater detail.

Pre-Operations Development of the GS Project Plans 

Before a Class VI permit may be issued, the owner or operator must develop and obtain the UIC 

Program Director’s approval of each of the five project plans. The initial plans are to be based on 

the extensive site-specific data collected during site characterization (e.g., geologic and 

geochemical data on subsurface formations and hydrologic data on aquifers), preliminary 

predictions of plume movement and pressure perturbations, and planned operational conditions. 

See the Draft UIC Program Class VI Well Site Characterization Guidance at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm for additional information on 

the types and collection of required site-specific data. 

Owners or operators must submit the five proposed GS project plans with their Class VI permit 

application. The UIC Program Director should evaluate the proposed plans in the context of 

other geologic and operational data submitted with the Class VI permit application. The owner or 

operator and the UIC Program Director are encouraged to discuss the plans as they are written 

and evaluated (especially while site-specific data are being collected). This coordination can 

improve the likelihood that the proposed plans will be approved and help both the owner or 

operator and the UIC Program Director anticipate any issues related to the operation of a GS 

project that may be of concern to the public. 

EPA recommends that owners or operators consider revising or adjusting portions of the project 

plans as additional data become available during the site characterization process. All five of the 

project plans must be submitted with the Class VI permit application, i.e., prior to operation of 

the injection well or drilling of any test wells. (While a stratigraphic test well that is not an 

injection well does not require a Class VI permit, if drilling one is planned, EPA recommends 

that the owner or operator and UIC Program Director discuss this to ensure that all planned 

activities associated with the test well would support an approvable Class VI permit application.)

Therefore, the owner or operator will need to develop the plans prior to the formal modeling of 

the AoR. 

While certain preliminary information would be available prior to AoR modeling, e.g., the 

estimated extent of the AoR based on initial geologic data and planned injection volumes, EPA 

recommends that the owner or operator revisit and revise the operational-phase plans (e.g., the 

AoR and Corrective Action Plan, Testing and Monitoring Plan, and Emergency and Remedial 

Response Plan) as necessary once the AoR modeling has been completed. This would, for 

example, help ensure that the AoR and Corrective Action Plan addresses all improperly 

abandoned artificial penetrations throughout the delineated AoR, that planned testing and 
UIC Program Class VI Well Project Plan 5 August 2012

Development Guidance 

monitoring is thorough, or that the Emergency and Remedial Response Plan addresses all 

potential resources and infrastructure that may be impacted by the project. 

Unless the site characterization or pre-injection testing revealed information about the site that is 

significantly different than the data on which the plans were based, finalization of the plans 

should not entail major revisions to the plans; instead, EPA anticipates that only slight 

adjustments to the plans would be needed to incorporate the latest available information about 

the site. However, if the AoR or any of the project plans require significant changes based on the 

final site characterization data, the permit would have to be modified. Depending on the extent of 

the modifications, the UIC Program Director may need to re-initiate the public notice process. To 

avoid any potential delays associated with this, EPA encourages owners or operators to collect as 

much site-specific data as possible before submitting the initial Class VI permit application.

In their discussion of the plans, EPA recommends that the owner or operator and UIC Program 

Director consider the advantages of tailoring activities to project conditions, and not necessarily 

performing only the minimum activities required by the Class VI Rule. For example, increasing

the number of monitoring locations or the frequency of AoR reevaluations may help ensure that 

future reviews of the project plans will not necessitate amendments or permit modifications. 

Owners or operators planning to deploy certain technologies several years into the life of the 

injection project (e.g., bringing additional monitoring wells online) may want to consider 

building the deployment schedule into the appropriate project plan so that adding or modifying a 

technique would not necessitate a permit modification (see below). This type of proactive 

planning early in the process may help ensure that the owner or operator and the UIC Program 

Director have considered both the current and possible future conditions at the proposed Class VI

injection well site based on all available site-specific information. 

Plan Reviews and Amendments 

Throughout the operational (injection) phase of a GS project, owners or operators will collect 

operating data (e.g., injection pressures, volumes, rates) and monitoring data (e.g., the position of 

the carbon dioxide plume and pressure front, ground water quality data). In addition to verifying 

that the site is operating as planned/modeled, this data will inform reevaluations of the AoR [40 

CFR 146.84(e)] and any subsequent project plan revisions and amendments. 

The AoR reevaluation involves the comparison of recently collected monitoring data to earlier

model predictions, which must take place at least every five (5) years [40 CFR 146.84]. Based on 

these comparisons, the AoR delineation model may need to be modified or run again in order to 

incorporate additional monitoring, site characterization, or operational data. Within one (1) year 

of an AoR reevaluation, the owner or operator must review the AoR and Corrective Action Plan, 

Testing and Monitoring Plan, and the Emergency and Remedial Response Plan, and determine if 

any amendments are necessary. 

Following this project plan review, the owner or operator must either submit amended project 

plans to the UIC Program Director or submit information that demonstrates why no amendments 

to the project plans are needed. Amended project plans must be subsequently approved by the 

UIC Program Director. (Periodic amendments of the Injection Well Plugging Plan and the PISC 
UIC Program Class VI Well Project Plan 6 August 2012

Development Guidance 

and Site Closure Plan are not required throughout the operational phase of the project because 

these plans would not be implemented until the cessation of injection operations.) 

The amended plans would then be incorporated into the Class VI operating permit, which would 

constitute a modification of the permit. Unless the modification to the permit is a minor 

modification (as defined at 40 CFR 144.41), a draft modified permit must be prepared and the 

procedures specified in 40 CFR Part 124 (public participation) must be followed. For additional 

information regarding the procedures that must be followed for a Class VI permit modification, 

see 40 CFR 144.39, as well as the Draft UIC Program Class VI Implementation Manual. 

The five GS project plans are inter-related. Changes to (or information acquired through the 

implementation of) one plan may necessitate a review of, or possibly a change to, some or all of 

the other plans. For example, data collected pursuant to the approved Testing and Monitoring 

Plan will inform the AoR reevaluation, which may, in turn, indicate that a revision of the 

Emergency and Remedial Response plan is needed. Plan reviews and amendments may also be 

triggered if there are indications based on monitoring data (collected per the approved Testing 

and Monitoring Plan) that the site is not performing as predicted. Table 1 presents examples of 

how, in the course of implementing one plan, changes may be identified that trigger the need for 

review of—and possible amendments to—the other project plans associated with a GS project.

Note that the list presented in Table 1 is not intended to be exhaustive.
UIC Program Class VI Well Project Plan 7 August 2012

Development Guidance 

Table 1. Examples of Interaction of Class VI Injection Well Project Plans

Plan Changes identified in 

implementing the plan

Potential impacts on other plans

AoR and Corrective 

Action Plan

Revised modeling delineates a 

larger/differently shaped AoR 

• Amend the AoR and Corrective Action Plan 

to address newly identified deficient wells

• Add monitoring locations to the Testing and 

Monitoring Plan

• Revise the Emergency and Remedial 

Response Plan if new resources/

infrastructure are identified in the AoR

Testing and 

Monitoring Plan

Ground water monitoring 

indicates leaching/mobilization 

of toxic metals or organics

• Adjust corrective action methods to address 

water quality changes

• Adjust injection well plugging methods

• Modify operational and post-injection 

ground water monitoring

Monitoring detects impairment 

of a USDW

• Implement the Emergency and Remedial 

Response Plan

• Modify operational and post-injection 

ground water monitoring

Monitoring indicates the 

carbon dioxide plume is 

moving faster than predicted, 

or in a different direction

• Adjust corrective action schedule; conduct 

more frequent AoR reevaluations 

• Expand ground water monitoring/pressure 

monitoring network

Pressures within the injection 

zone vary from modeled 

predictions

• Adjust post-injection pressure monitoring

• Reevaluate AoR, considering current 

pressure data

• Revise AoR and Corrective Action Plan

PISC and Site Closure 

Plan

Monitoring detects ground 

water contamination or plume 

excursions

• Implement Emergency and Remedial 

Response Plan 

• Modify post-injection monitoring regime

Emergency and 

Remedial Response

Plan

An adverse event required 

implementation of Emergency 

and Remedial Response Plan

• Revisit all plans to identify lessons learned

A detailed and thorough periodic reevaluation of the AoR, and the review and applicable 

revisions of the project plans throughout the life of the project are key components of the Class

VI Rule. EPA recommends that the plans be reviewed simultaneously to promote a holistic 

approach that considers all available information and ensures that the site is managed in a 

manner that protects USDWs from endangerment. This iterative plan review and revision 

process is unique in the UIC Program for Class VI wells, and it is required in place of the 

periodic permit renewals conducted for other injection well classes regulated under the UIC 

Program. Linking GS project plan reviews to the AoR reevaluation frequency will ensure that 

these reviews are conducted on a defined schedule (i.e., no less than every five [5] years). This 

adds little burden on the Class VI injection well owner or operator if the AoR reevaluation 

confirms that the project plans are appropriate and can continue to be implemented as written.

There are reasons other than the AoR reevaluation to update project plans. For example, it may 

be necessary to review the project plans outside of the AoR reevaluation cycle, and owners or 

operators should consider updating their GS project plans whenever monitoring or operational 

data indicate such a need. Owners or operators may also consider planning for more frequent 
UIC Program Class VI Well Project Plan 8 August 2012

Development Guidance 

reevaluations or project plan reviews early in the project life, when unexpected results are most 

likely to arise. While it is possible that fewer unanticipated events would occur in the later years 

of injection, owners or operators must reevaluate the AoR and determine whether updates to the 

plans are needed at least every five (5) years, as required at 40 CFR 146.84(e).

1.3 Other Relevant Guidance

Other Draft UIC Program Class VI guidance documents prepared by EPA on specific technical 

aspects of GS projects provide additional, more technically detailed information on the activities 

to be included in the GS project plans than is provided in this guidance. The Draft UIC Program 

Class VI guidance documents can be found on EPA's website at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm: 

• The Draft UIC Program Class VI Well Area of Review Evaluation and Corrective 

Action Guidance: This draft guidance document describes recommended approaches to 

apply computational modeling to delineate the AoR, perform corrective action at GS sites, 

and periodically reevaluate the AoR. It contains information that will support the 

development of the AoR and Corrective Action Plan for a proposed GS project. 

• The Draft UIC Program Class VI Well Testing and Monitoring Guidance: This draft 

guidance document describes the available technologies for implementing a Testing and 

Monitoring Plan for a Class VI injection well site, including well testing such as MITs and 

corrosion monitoring, groundwater quality monitoring, carbon dioxide plume and pressure 

front tracking, and surface air and/or soil gas monitoring (which may be required by the UIC 

Program Director). It contains information that will support the development of the required 

Testing and Monitoring Plan for a proposed GS project. 

• The Draft UIC Program Class VI Well Plugging, Post Injection Site Care (PISC) and 

Site Closure Guidance: This draft guidance document describes how EPA recommends that 

owners or operators plug injection and monitoring wells, and perform post-injection 

monitoring, non-endangerment demonstrations, and site closure activities. It contains 

information that will support the development of the required Injection Well Plugging Plan 

and the PISC and Site Closure Plan and explains how owners or operators can demonstrate 

that an alternative PISC timeframe is appropriate. 

Additionally, three other Agency guidance documents address topics related to the development 

or submittal of the GS project plans: 

• The UIC Program Class VI Financial Responsibility Guidance explains the requirements 

related to demonstrating and maintaining financial responsibility for corrective action on 

wells in the AoR, injection well plugging, PISC and site closure, and emergency and 

remedial response at 40 CFR 146.85. Since many of these activities will be performed 

pursuant to UIC Program Director-approved GS project plans, the coordination of activities 

associated with demonstrating financial responsibility and developing the project plans is 

crucial so that cost estimates for financial responsibility demonstrations accurately address 

all the covered injection well operation, monitoring, and post-injection activities. EPA 
UIC Program Class VI Well Project Plan 9 August 2012

Development Guidance 

recommends that the financial responsibility demonstration requirements be considered

throughout the development, implementation, and future amendments to the GS project 

plans. 

• The Draft UIC Class VI Implementation Manual provides recommendations for UIC 

Program Directors as they consider various types of information about the site when 

evaluating and approving the project plans, including areas on which the UIC Program 

Director is afforded discretion in setting permit criteria or reviewing the project plans. 

• The Draft UIC Program Class VI Well Recordkeeping, Reporting, and Data 

Management Guidance provides detailed information for owners or operators on how to 

submit all required data for a permitted Class VI injection well, including how to submit the 

five project plans and any necessary amendments. 

Other EPA-developed guidance documents available to assist owners or operators of Class VI

wells address: the site characterization process, well construction, injection depth waivers for 

Class VI wells, and transitioning wells from Class II to Class VI. 

1.4 Organization of this Document 

The next five Sections of this guidance describe each of the five GS project-specific plans as 

follows: 

Section 2 – AoR and Corrective Action Plan

Section 3 – Testing and Monitoring Plan 

Section 4 – Injection Well Plugging Plan 

Section 5 – Post-Injection Site Care and Site Closure Plan 

Section 6 – Emergency and Remedial Response Plan

For each of the required plans, the following is described: 

• Developing the plan (Sections 2.1, 3.1, 4.1, 5.1, and 6.1): these Sections describe the required 

content of the plan as specified in the Class VI Rule, recommended approaches for 

developing plans that meet EPA's requirements, and the site-specific considerations that EPA 

recommends owners or operators account for in developing each plan. 

• UIC Program Director’s evaluation of the plan (Sections 2.2, 3.2, 4.2, 5.2, and 6.2): these 

Sections describe—for the benefit of the owner or operator—what the UIC Program Director

should consider and evaluate as he/she reviews the proposed plan, including any areas of 

UIC Program Director’s discretion regarding the Class VI Rule requirements. 

• Amending the plan (Sections 2.3, 3.3, 4.3, 5.3, and 6.3): these Sections describe the 

recommended scope of the periodic review of each plan and information that EPA 

recommends to be considered in the course of the review, the timing of the review, and what 

must be reported to the UIC Program Director [40 CFR 146.84(e), 146.90(j), 146.92(c), 

146.93(a)(3), and 146.94(d)]. 

Appendices A through E contain sample templates for each of the required project plans. 
UIC Program Class VI Well Project Plan 10 August 2012

Development Guidance 

Note that each Section of this guidance provides a thorough discussion of the process for 

development, evaluation, and review/amendment of each of the required plans. Therefore, there

is some repetition when the processes are the same for the different plans. Each Section of this 

Plan Development guidance is intended to serve as a “how to” manual for each individual plan. 

2.0 Area of Review and Corrective Action Plan

Owners or operators of Class VI injection wells must submit a Class VI Area of Review (AoR) 

and Corrective Action Plan that describes how they intend to delineate the AoR (using 

appropriate models and assumptions), address all deficient artificial penetrations within the AoR, 

and update the AoR modeling periodically throughout the life of the project. This comprehensive 

planning is necessary to ensure that an appropriate site-specific strategy is in place to predict the 

extent of the carbon dioxide plume and pressure front (i.e., to delineate the AoR) and ensure that 

all deficient artificial penetrations within the AoR that could serve as conduits for fluid 

movement into USDWs are addressed through appropriate and timely corrective action methods. 

Implementation of the AoR and Corrective Action Plan also supports the development of 

effective monitoring strategies by identifying the locations where ground water quality or 

pressure monitoring should be performed. Additionally, data gathered by implementing the AoR 

and Corrective Action Plan will help direct emergency response planning by identifying potential 

vulnerable areas (e.g., public water supplies) within the AoR that could require consideration 

when implementing an emergency response. AoR and Corrective Action Plans will also guide 

the ongoing process of periodic AoR reevaluations, which are essential to informed site 

management and monitoring over the lifecycle of the injection project. 

2.1 Developing the AoR and Corrective Action Plan 

The Class VI Rule, at 40 CFR 146.84(b), presents the required content of an AoR and Corrective 

Action Plan for a GS project. In the proposed AoR and Corrective Action Plan, the owner or 

operator must demonstrate to the satisfaction of the UIC Program Director that the modeled AoR 

will be based on the detailed site-specific geologic data collected during the site characterization 

process and that all necessary corrective action within the modeled AoR will be performed in a 

timely manner to protect USDWs. 

Guidance and recommended approaches on performing the activities to be carried out under the 

approved plan (e.g., performing AoR delineation modeling and addressing wells that require 

corrective action) are presented in the Draft UIC Program Class VI Well Area of Review 

Evaluation and Corrective Action Guidance, available on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm. Exhibit 2 presents highlights 

of the information presented in that guidance. 
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Development Guidance 

Exhibit 2: Draft UIC Program Class VI Well AoR Evaluation and Corrective Action 

Guidance Highlights

The Draft UIC Program Class VI Well Area of Review Evaluation and Corrective Action Guidance provides EPA 

recommendations regarding modeling to delineate the AoR for a GS project, under what circumstances the AoR is 

reevaluated, and performing AoR reevaluations. In addition, the guidance covers recommended approaches to 

identify, evaluate, and perform corrective action on any artificial penetrations identified within the delineated AoR 

that require remediation. 

The introductory Section reviews the definition of the AoR for Class VI projects and Class VI regulations pertaining 

to AoR and corrective action. Remaining Sections of the guidance address the following topics:

• The data to be considered in running a model for the initial AoR delineation;

• The computational modeling needed to delineate the AoR;

• The identification and evaluation of, and performing corrective action on, artificial penetrations located within 

the delineated AoR; and

• AoR reevaluations.

For each Section, the guidance:

• Explains how to perform activities necessary to comply with the Class Rule AoR and corrective action 

requirements (e.g., performing computational modeling). Illustrative examples are provided in several cases.

• Provides references to other, more comprehensive documents and published scientific literature for further 

information.

• Explains how and when to report to the UIC Program Director the results of activities related to AoR and 

corrective action.

VI 

The AoR and Corrective Action Plan must be submitted with the Class VI permit application for 

approval by the UIC Program Director [40 CFR 146.82(a)(13)], and must include a description 

 AoR and corrective action requirements [40 

CFR 146.84]. The Sections below provide a description of the required content of the AoR and 

Corrective Action Plan, how EPA recommends the content be described in the plan to 

injection 

well owners or operators might consider as they develop their plan. Appendix A of this guidance 

document presents a sample template of an AoR and Corrective Action Plan.

demonstrate that the plan is sufficient and approvable, and other topics that Class

of how the owner or operator will meet the Class VI

VI

2.1.1 The method for delineating the AoR 

The Class VI Rule requires Class VI injection well owners or operators to describe in their AoR 

and Corrective Action Plan how they will delineate the AoR. Specifically, the plan must describe 

the computational model that will be used for the AoR delineation process, the assumptions that 

will be made, and the site characterization data on which the model will be based [40 CFR 

146.84(b)(1)]. 

Several computational codes are available that are appropriate for modeling to delineate the AoR 

for Class VI wells. EPA recommends that the model be appropriate to the site-specific geologic 

conditions (i.e., be able to accurately predict movement of the plume and pressure front, given
UIC Program Class VI Well Project Plan 12 August 2012

Development Guidance 

the particular geologic conditions at the site), and the model must meet the requirements 

specified in the Class VI Rule [40 CFR 146.84(c)(1)]. See Section 3 of the Draft UIC Program 

Class VI Well AoR Evaluation and Corrective Action Guidance for additional information on the 

required AoR modeling for a Class VI injection well.

A detailed geologic site characterization is essential to evaluating the presence and adequacy of 

the geologic formations in a proposed area to both receive and confine the injected carbon 

dioxide. The AoR and Corrective Action Plan must describe the site characterization data on 

which the model will be based (e.g., porosity, permeability, geochemistry, artificial penetrations, 

or stratigraphy). As discussed in Section 1, developing the plan will be an iterative process. 

Developing and submitting a plan before the well is drilled will ensure that the owner or operator 

and UIC Program Director agree on the approach, while allowing for the plan to be adjusted if 

necessary as information is gathered during drilling and pre-operational testing. See the Draft 

UIC Program Class VI Well Site Characterization Guidance for details on collecting this data, 

including the use of stratigraphic test wells, and the Draft UIC Program Class VI Well AoR 

Evaluation and Corrective Action Guidance for EPA-recommended approaches for 

incorporating this data into AoR delineation modeling. 

Additionally, prior to authorizing injection, the UIC Program Director should evaluate the 

delineated AoR along with all information submitted regarding the model and its assumptions. 

This evaluation is necessary to ensure that the delineated AoR encompasses a sufficient area in 

which corrective action will be performed so that no improperly constructed, plugged, or 

abandoned wells are present that could serve as conduits for fluid movement into USDWs. An 

AoR and Corrective Action Plan that includes a detailed and complete description of the model 

and its planned inputs will be helpful for the UIC Program Director and facilitate and expedite 

the review of the plan. 

EPA recommends that the owner or operator convey in the plan to the UIC Program Director 

how the model’s code, input, and assumptions will be considered or accounted for, and that the 

model will appropriately address local conditions and delineate an accurate AoR. Owners or 

operators might use the following types of information when selecting a computational modeling 

code for the AoR delineation and developing input parameters and assumptions: 

Site Geology and Hydrogeology Information 

• The type and number of subsurface formations from the surface to the injection zone, 

as determined by borehole sampling and logging, geophysical, and other tests or methods 

to characterize the site geology;

• For each formation, initial fluid pressures, horizontal and vertical gradients, and ground 

water flow directions and velocity; 

• The presence and characterization of faults or fractures; 

• The presence of wells and mines; 

• Baseline geochemistry and the compatibility of the carbon dioxide stream with fluids in 

the injection zone and minerals in the subsurface formations; 

• Multiphase flow parameters, and relevant permeability-saturation relationships and 

equations of state; and
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Development Guidance 

• The measures of porosity and permeability (and/or geostatistical or stochastic estimates 

of these parameters). 

Proposed Operating Data and Information 

• Proposed injection rates, pressures, and well depths; 

• The presence, or planned presence, of other injection (or production) wells, including 

Class VI injection wells operated as part of separate projects, within the injection zone or 

other pertinent zones; and

• Information on all USDWs above the injection zone. If an injection depth waiver is 

sought, all USDWs above and below the injection zone. 

2.1.2 The minimum fixed frequency to reevaluate the AoR 

The Class VI Rule requires owners or operators to periodically reevaluate the AoR to incorporate 

monitoring and operational data. In the plan, owners or operators must describe the minimum 

frequency at which this reevaluation will occur [40 CFR 146.84(b)(2)(i)]. In no case can this 

reevaluation happen less frequently than every five (5) years from the date on which the UIC 

Program Director grants approval for operation per 40 CFR 146.82(c). However, it may be 

appropriate to reevaluate the AoR more frequently based on site-specific information, as 

described below. This may be particularly important for the first reevaluation to verify, once 

injection commences, that the carbon dioxide plume is behaving in the subsurface as predicted. 

Owners or operators with multiple permitted wells at the same site may also opt to modify the 

reevaluation schedule for wells brought online later to consolidate the reevaluation schedule for 

all of the wells. 

Below are some factors to consider when determining the minimum AoR reevaluation 

frequency, including whether a reevaluation more frequently than every five (5) years would be 

appropriate. EPA recommends that the AoR and Corrective Action Plan describe how these 

factors were considered in determining the AoR reevaluation frequency.

• The presence of multiple injection wells or planned additional injection wells: a

reevaluation may be warranted once all of the injection wells come online, or after a 

threshold volume of carbon dioxide has been injected;

• The pace of population growth and development or land use changes in the region: 

rapid growth may indicate that additional public and private wells have been drilled or 

that ground water supplies within the AoR are being developed for use; 

• Planned phased corrective action (see Section 2.1.5): an AoR reevaluation may be 

warranted following commencement of injection and after a significant number of wells 

are plugged; 

• Confidence in the modeling assumptions or the amount and quality of site 

characterization data that will be used for AoR delineation or the general modeling 

approach: significant uncertainties in site characterization data and the AoR delineation 

modeling may be addressed by more frequent reevaluation and comparison to monitoring 

data, particularly early in the project; 
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Development Guidance 

• Project duration: owners or operators of short-duration projects (i.e., injecting for less 

than five [5] years) should consider planning for at least one AoR reevaluation or review 

of monitoring and operating data during the life of the project;

• Injection volumes and rates: UIC Program Directors may consider that higher volume 

projects warrant more frequent reviews, particularly early in the injection phase; 

• Planned changes in operation: these changes may include the addition of injection 

wells, changes to injection or production rates (e.g., associated with enhanced oil 

recovery operations or dewatering/depressurization), or a change in the source of the 

carbon dioxide; and 

• Public acceptance: if the public expresses concerns about the project (e.g., about safety 

or environmental justice considerations) or if the public opposes the proposed siting of a 

Class VI injection well, the publication of GS project monitoring results and an early 

AoR reevaluation may help allay some of these concerns.

2.1.3 Conditions that would warrant an early AoR reevaluation 

It may be necessary, based on site-specific circumstances or events, to reevaluate the AoR before 

the next planned reevaluation (see Section 2.1.2 of this guidance document). The owner or 

operator must describe in the AoR and Corrective Action Plan what monitoring or operational 

conditions may warrant a reevaluation of the AoR prior to the next scheduled reevaluation [40 

CFR 146.84(b)(2)(ii)]. EPA recommends that the owner or operator convey in the plan how the 

following monitoring data and operating conditions would be considered in determining the need 

for an unscheduled AoR reevaluation: 

• If monitoring data reveal an unexpected change in the rate or direction of carbon dioxide 

plume movement, the areal extent of the plume, or formation pressures; 

• Changes in operation, including the addition of injection wells, changes to injection 

rates or volumes injected, a change in production rates from the injection zone (e.g., 

associated with enhanced oil recovery operations or dewatering/depressurization), or 

changing the source of the carbon dioxide. Similarly, if other owners or operators plan 

to inject into the same formation as the subject Class VI well and their pressure effects 

are anticipated to influence the well, then the AoR should be reevaluated to incorporate 

those effects;

• Following any seismic event, whether related to the GS project or not (the area over 

which seismic events are considered would be site-specific); 

• Following an exceedance of any Class VI operating permit condition (e.g., exceeding 

the permitted volumes of carbon dioxide injected); or 

• Newly available site characterization data that may impact model predictions. 

2.1.4 How monitoring and operational data will inform AoR reevaluations 

The Class VI Rule requires that the AoR delineation and reevaluations account for all available 

operating, site characterization, and monitoring data. Owners or operators must describe in the 

AoR and Corrective Action Plan how these data will be incorporated into the AoR reevaluation; 

e.g., how the data will be collected and compared to model predictions, and if necessary, 

incorporated into future modeling runs [40 CFR 146.84(b)(2)(iii)]. 
UIC Program Class VI Well Project Plan 15 August 2012

Development Guidance 

An AoR reevaluation may not necessarily need to result in additional modeling or changes to the 

site computational model. If, based on a comparison of the site monitoring data, project 

information, and the current AoR model predictions, the owner or operator determines that no 

changes to the model are necessary, then the owner or operator need only demonstrate to the UIC 

Program Director that no model revision is necessary. EPA recommends that the plan discuss 

how monitoring and modeling data will be compared, and how this demonstration of no model 

revision will be made, if that demonstration is appropriate. 

In the event that the owner or operator determines that revisions to the model are necessary, the 

plan must discuss how the newly available data will be used to revise the model and AoR 

delineation [40 CFR 146.84(b)(2)(iii)]. EPA recommends that these discussions tie closely to 

how operating data will be collected and how the Testing and Monitoring Plan will be 

implemented (see Section 3 of this guidance document). Owners or operators may consider 

factors similar to those used to incorporate the site characterization data into the original model. 

EPA recommends that the revised AoR and Corrective Action Plan discuss how the owner or 

operator intends to consider the following: 

• How specific types of monitoring data (e.g., ground water quality or plume tracking 

results) will be quantitatively compared to modeling results: EPA recommends that 

the plan outline under what conditions deviations between monitoring data and model 

results will be deemed “significant” and trigger a revision of the site computational 

model and AoR delineation; 

• How model parameters will be adjusted to reflect monitoring data (i.e., model 

calibration process) if a model revision is necessary; 

• How operational parameters (injection rate, injection pressure, and the total volume 

injected) will be compared to the original model inputs: EPA recommends that the 

plan outline when (and the threshold magnitude for which) deviations between model 

inputs and actual operational conditions warrant a revision of the computational model 

and AoR delineation; 

• How newly available site characterization data will be compared to existing data

used as model input parameters, and under what conditions newly available site 

characterization data will trigger a revision of the computational model and AoR 

delineation; and

• How the impacts of other injection well owners or operators in the AoR (or new 

owners or operators), including consideration of their operating procedures, may affect or 

require alterations to the modeling.

2.1.5 How corrective action will be conducted

Owners or operators of all classes of injection wells, including Class VI injection wells, must 

perform corrective action on all improperly plugged artificial penetrations identified within the 

delineated AoR in order to ensure that they will not serve as conduits for fluid movement into 

USDWs. All improperly plugged artificial penetrations within the AoR must be plugged using 

materials that can withstand the potentially corrosive environment that results when the carbon 

dioxide stream mixes with formation fluids [40 CFR 146.84(d)]. Additionally, at 40 CFR 
UIC Program Class VI Well Project Plan 16 August 2012

Development Guidance 

146.84(b)(2)(iv), the Class VI Rule affords owners or operators the option (if approved by the 

UIC Program Director) of phased corrective action, (i.e., deferring corrective action for those 

wells that are not expected, based on modeling and site-specific information, to be impacted by 

the carbon dioxide plume or pressure front for several years).

The AoR and Corrective Action Plan must describe how the corrective action will be performed, 

including the corrective action methods to be used, the schedule for completing all corrective 

action, and what corrective action will be phased [40 CFR 146.84(b)(2)(iv)]. The plan must 

address all wells in the AoR that are determined to need corrective action. It may be appropriate 

to include a table that lists all wells identified within the AoR that need corrective action, the 

scheduled date for performing corrective action (both pre-injection and during injection 

operations), and the planned corrective action method(s). Specific information on determining 

the appropriate corrective action methods and schedule for completion is presented below.

Corrective Action Methods

The Class VI Rule requires that all improperly plugged artificial penetrations located within the 

AoR be addressed, but it does not specify the corrective action methods to be used. Instead, the 

Class VI Rule affords flexibility in order to ensure that all corrective action methods employed 

are appropriate to the specific artificial penetration needing plugging, the characteristics of the

injectate, and any other site-specific conditions that may be warranted (e.g., the formation

geochemistry). 

The AoR and Corrective Action Plan must describe the specific corrective action activities that 

will be taken for each type of improperly plugged artificial penetration located within the AoR 

(e.g., depth and type of plugs; cement to be used). Well schematics may be appropriate. 

Section 4 of the Draft UIC Program Class VI Well AoR Evaluation and Corrective Action 

Guidance describes how to identify improperly plugged artificial penetrations within the AoR, 

assess their integrity, and perform corrective action when necessary. EPA recommends that the 

AoR and Corrective Action Plan convey how the following factors about the site and the 

artificial penetrations within the AoR will be considered in determining the appropriate 

corrective action methods: 

• The age of each improperly plugged well, the condition of the cement, and the overall 

maintenance of the improperly plugged well (including maintenance records or the 

lack thereof); 

• Well depth, which would affect the number of plugs and the types and amount of cement 

needed; 

• The composition of the carbon dioxide stream, formation fluid geochemistry, and 

the presence of other corrosive native fluids (e.g., hydrogen sulfide), which can 

interact to impact the potential formation of carbonic acid that could react with or 

degrade well materials or cements; 

• The presence of all USDWs and the characteristics of the formations penetrated by 

the well, which may affect the number of plugs and the amount and types of cement 

required; and
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Development Guidance 

• The remedial techniques that will be used to address improperly plugged wells within 

the AoR. 

Corrective Action Schedule 

The AoR and Corrective Action Plan must include a schedule for completing corrective action 

on all improperly plugged wells located within the AoR. The Class VI Rule allows for phased 

corrective action, so that improperly plugged wells that are not anticipated to be intersected by 

the carbon dioxide plume and pressure front for several years may not need to be addressed prior 

to commencing injection. However, for improperly plugged wells that will need corrective action 

prior to injection, and whenever otherwise practical, EPA recommends that the AoR and 

Corrective Action Plan include approximate timeframes for performing corrective action. The 

plan should also include a schedule for performing corrective action on all improperly plugged 

wells located within the AoR that are determined to need corrective action (i.e., which wells will 

be plugged in year 1, year 2, etc.). EPA encourages owners or operators to be as specific as 

possible in identifying the dates of planned corrective action activities or notify the UIC Program 

Director when the dates are set to give the UIC Program Director an opportunity to witness the 

corrective plugging activities. 

The AoR and Corrective Action Plan must describe the following [40 CFR 146.84(b)(2)(iv)]:

• What corrective action will be performed prior to the start of injection: The plan must 

demonstrate that all improperly plugged wells located within the AoR that are determined 

to need corrective action, and are likely to be intersected by the carbon dioxide plume and 

pressure front early on, will receive corrective action in a timely manner. This 

determination would be tied to modeled predictions of the rate of plume movement. If 

phased corrective action is approved, pre-injection corrective action would only be 

necessary in areas with a high certainty of carbon dioxide exposure during the first 

several years of injection as informed by site characterization data and modeling. 

Conversely, if modeling indicates that the injected carbon dioxide plume and pressure 

front will expand throughout the AoR in a short time, all corrective action should be 

completed prior to the initiation of carbon dioxide injection operations. 

• What corrective action will be phased: If phased corrective action is planned, the AoR 

and Corrective Action Plan must describe which portions of the AoR will have corrective 

action performed on a phased basis. The plan must also describe how the phasing was 

determined; i.e., it must justify why corrective action on certain improperly plugged wells 

can be deferred until a later date, based on modeled predictions. 

It is important to note that phased corrective action must be approved by the UIC 

Program Director. If an owner or operator seeks to phase corrective action, consultation 

with the UIC Program Director is encouraged in order to identify whether phased 

corrective action is appropriate based on information about a proposed Class VI injection 

well site and to avoid unnecessary delays in injection operations. 
UIC Program Class VI Well Project Plan 18 August 2012

Development Guidance 

To ensure that corrective action activities on all improperly plugged wells will be 

possible, the owner or operator must also describe in the plan how surface access to all 

wells needing corrective action will be guaranteed. The owner or operator will need to 

obtain the right of access to improperly plugged wells in order to perform the necessary 

corrective action and demonstrate in their submitted AoR and Corrective Action Plan that

these access rights have been granted. This demonstration may include information 

regarding how the owner or operator will maintain current information on land ownership 

changes or enter into necessary agreements with current land owners to be able to access 

and address the improperly plugged wells. If surface access rights cannot be guaranteed, 

or if additional development of the land area around the improperly plugged well is 

anticipated, it may be beneficial to complete all corrective action activities prior to

commencing injection activities or prior to the additional land development.

• How the corrective action schedule will be adjusted if there are changes in the AoR: The 

plan must also describe how any changes to the delineated AoR will be addressed (i.e., if 

the reevaluation determines that the carbon dioxide plume is moving differently than 

modeled/expected). For example, EPA recommends that the plan describe how additional 

improperly plugged wells will be identified and corrected expeditiously in advance of 

being intersected by the carbon dioxide plume or pressure front. 

While every attempt must be made to identify and address all wells needing corrective action, 

some corrective actions may need to be conducted on an emergency basis. Owners or operators 

should consider this possibility and develop procedures for implementing emergency corrective 

actions (see also Section 6.1 on emergency and remedial response planning). Owners or 

operators might consider the following factors in determining which improperly abandoned wells

located within the AoR need to be corrected prior to initiating injection and in developing the 

corrective action schedule to be submitted with the plan. EPA recommends that the owner or 

operator convey in the plan how these factors will be considered in complying with the Class VI

Rule corrective action requirements: 

• Any predictions of plume or pressure front migration rates that may be available 

during the preparation of the plan; 

• The historical use of wells and the location and density of artificial penetrations in the 

AoR of the well. For GS projects in saline reservoirs, there may be few, if any, existing 

well bores. However, older/well-developed oil and gas fields may have a significant 

number of wells. 

• The number of deficient wells. If there are many improperly plugged wells to correct, 

then the corrective action implementation schedule may need to account for a larger 

effort; and

• The pace of development or land use changes in the region, which may increase the 

chance that additional wells, including other Class VI injection wells will be drilled (or 

abandoned) between AoR evaluations. 
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Development Guidance 

2.2 UIC Program Director’s Evaluation of the AoR and Corrective Action Plan 

The UIC Program Director must evaluate the proposed AoR and Corrective Action Plan, along 

with the geologic and proposed operating data submitted with the Class VI permit application in 

order to determine whether to approve the plan. Therefore, the owner or operator must 

demonstrate in the proposed plan, to the UIC Program Director’s satisfaction, that implementing 

the plan will result in: an appropriately modeled AoR, a thorough identification of the 

improperly plugged wells located within the AoR, and a justifiable schedule for correcting all 

deficient wells located within the AoR. 

The UIC Program Director should evaluate the proposed AoR and Corrective Action Plan to 

verify that all of the required elements, as described in 40 CFR 146.84(b), are present and that 

the plan accounts for all of the site-specific conditions that need to be addressed in order to 

ensure that USDWs will be protected from endangerment. Examples of possible considerations 

by the UIC Program Director are given below:

Examples of Considerations Related to the AoR Delineation: 

• Is the code that will be used to develop the AoR delineation model sufficient to accurately 

predict movement of the carbon dioxide plume and pressure front; and does it have the 

capability to incorporate multiphase flow, the relative buoyancy of carbon dioxide, and threedimensional geologic heterogeneity?

• Does the proposed model incorporate all relevant site geology, data on subsurface pressures 

and fluid movement, and proposed operating data submitted with the Class VI permit 

application? 

• Have sensitivity analyses of the model been performed; do they corroborate the initial 

modeling results?

• Is sufficient information submitted regarding modeling assumptions, including relative 

permeability/saturation relationships and equations of state?

• Is the proposed AoR reevaluation schedule appropriate based on the operational conditions or 

anticipated monitoring data? 

• Have the geologic factors and operational conditions that could warrant a change in the 

reevaluation schedule been included in the plan? 

Examples of Considerations Related to Corrective Action:

• Has a reasonable effort been made to locate all improperly plugged wells located within the 

AoR? Has the condition of each improperly plugged well been established, and based on this 

information, is the plan sufficient to ensure that no wells in the AoR will serve as conduits 

for fluid movement into USDWs? 

• Are the remediation techniques proposed to be used appropriate to the number and condition 

of all the improperly abandoned wells located within the AoR? 

The UIC Program Director has discretion to allow for phased corrective action activities. In 

determining whether to exercise this discretion, the UIC Program Director may consider:
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• The proposed carbon dioxide injection rate, total injection volumes, and the duration of 

the project; 

• The composition of the carbon dioxide stream and potential impacts on native/formation 

fluids and the rock matrix; 

• The density of artificial penetrations in the vicinity of the injection project; 

• The anticipated number of wells that will need corrective action, and possible “work 

load” issues in addressing all of the deficient wells in a large or densely penetrated AoR; 

• Whether there is a guarantee that all wells can be accessed and remediated at the 

appropriate time; and

• The AoR delineation modeling uncertainty and the resulting impact on the size and shape of 

the AoR. 

The submittal, evaluation, and approval of the AoR and Corrective Action Plan may be an 

iterative process, involving multiple drafts, until all the information required is submitted at the 

appropriate level of detail, as determined by the UIC Program Director. If the UIC Program 

Director has reason to believe (e.g., based on site-specific conditions) that additional data are 

needed to sufficiently address the anticipated risk associated with the proposed injection (e.g., 

through adjustments to the model or corrective action methods), it is within his/her authority to 

request that additional site-specific information be collected, or additional activities be included

and described in the AoR and Corrective Action Plan. 

EPA recommends that owners or operators consider revising portions of the AoR and Corrective 

Action Plan as site characterization data become available and modeling is performed. For 

instance, if AoR modeling indicates that the carbon dioxide plume and pressure front will move 

faster than initially anticipated based on preliminary geologic data (especially if abandoned wells 

are to be intersected by the carbon dioxide plume/pressure front), EPA recommends that the 

owner or operator consider whether the originally planned corrective action schedule is 

appropriate. Likewise, it may not be possible to prepare a final tabulation of all the improperly 

abandoned wells in the AoR that require corrective action until the AoR delineation modeling is 

complete. 

The owner or operator and the UIC Program Director are encouraged to discuss the AoR and 

Corrective Action Plan prior to final submittal, e.g., to review the advantages and disadvantages 

of various modeling approaches, whether to phase corrective action, etc. Such discussions prior 

to developing and submitting the proposed AoR and Corrective Action Plan can increase the 

chance that the plan will be approved and avoid any need to revise and resubmit the plan. This 

background preparation may also limit the need for future amendments to the AoR and 

Corrective Action Plan. The approved AoR and Corrective Action Plan (including all approved 

activities and schedules) is enforceable, whether or not the plan is a condition of the permit, 

because the plan itself and the UIC Program Director’s approval are required by the Class VI

Rule [40 CFR 146.84(b)]. 

Appendix F presents a checklist of questions and considerations that UIC Program Directors may 

use when evaluating the proposed AoR and Corrective Action Plan and other GS project plans. 

For additional information on the UIC Program Director’s evaluation of the plan, including 

exercising discretion regarding phased corrective action, see the Draft UIC Program Class VI
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Implementation Manual, available on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm. 

 

2.3 Amending the AoR and Corrective Action Plan 

The Class VI Rule requires that the AoR and Corrective Action Plan be reviewed and, if 

necessary, amended following each reevaluation of the AoR [40 CFR 146.84(e)]. The purpose of 

this review is to ensure that the management of the GS project is based on the most up-to-date 

information available in order to protect USDWs from endangerment. This review of the AoR 

and Corrective Action Plan follows the required AoR reevaluation, which must occur at least 

once every five (5) years (see the Draft UIC Program Class VI Well AoR Evaluation and 

Corrective Action Guidance for additional information on performing AoR reevaluations). 

Reevaluations of the AoR must continue throughout the life of the GS project, including the 

post-injection phase. It is likely that, following cessation of injection, the area of increased 

pressure will reduce in size as pressures dissipate. Therefore EPA expects that the reviews will 

entail an examination of monitoring data and confirmation and communication to the UIC 

Program Director that no modifications to the AoR or amendments to any plans are needed. 

However, this step is necessary to ensure that USDWs are not endangered and that all of the 

plans in force (i.e., including the PISC and Site Closure and Emergency and Remedial Response 

Plans) remain protective of USDWs. 

The owner or operator must submit the amended AoR and Corrective Action Plan to the UIC 

Program Director for approval following an AoR reevaluation or any other event that triggers an 

AoR and Corrective Action Plan review [40 CFR 146.84(e)]. EPA recommends that owners or 

operators submit the revised AoR and Corrective Action Plan along with revisions to the Testing 

and Monitoring Plan and the Emergency and Remedial Response Plan, both of which are due 

within (1) year of an AoR reevaluation, or within one (1) year of any other event that triggers an 

AoR reevaluation.

To assess the need for amending the AoR and Corrective Action Plan, EPA recommends that 

owners or operators use the results of the AoR reevaluation, along with monitoring data (e.g., 

carbon dioxide plume and pressure front tracking and ground water monitoring) and operational 

data (e.g., injection rates and volumes) collected since the last reevaluation. It is recommended 

that the owner or operator also undertake a review of the AoR and Corrective Action Plan if 

there are significant changes to the facility, such as the permitting of an additional injection well, 

or if any adverse events occur that require the implementation of an emergency response. 

EPA recommends that, as part of their ongoing dialogue, the owner or operator and the UIC 

Program Director discuss the most recent AoR delineation or reevaluation, along with 

monitoring and operational data collected, and any other pertinent information about the carbon 

dioxide injection operation during this plan review. This communication and coordination is an 

important part of the process to ensure that the GS project is (and continues to be) managed 

appropriately to protect USDWs, and that injection operations remain in compliance with permit

conditions. These discussions can also help the owner or operator understand the UIC Program 

Director’s expectations, including whether an amended plan might be needed, so that the UIC 

Program Director receives all the required information up front in order to facilitate the review 
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Development Guidance 

process. The Sections below describe a recommended process by which the owner or operator 

may review and amend the AoR and Corrective Action Plan: 

Step 1: Review the results of the AoR reevaluation or relevant monitoring and operational 

data. The purpose of this review is to identify whether an amendment to the AoR and Corrective 

Action Plan is needed. Questions and potential approaches that may be considered in the review 

include: 

• Did the most recent AoR reevaluation identify a need to revise the AoR computational 

model? If so, the AoR and Corrective Action Plan may need to be amended to reflect any 

changes to the modeling approach or the modeled AoR. 

• Do the most recent AoR modeling results closely match monitoring results? If not, it may be 

necessary to revise the model, adjust the modeling assumptions, and/or review or supplement 

input data. 

• Is the plume or pressure front moving faster or in a different direction than previously 

predicted? This may indicate that more frequent AoR reevaluation is appropriate. 

• Do additional wells need corrective action, or do some wells previously identified for 

corrective action need to be addressed earlier than planned, based on modeling results or 

monitoring data? Either of these situations may necessitate revisions and amendments to the 

corrective action plan. 

• Have land use changes potentially affected the owner’s or operator’s ability to secure rights 

to access wells identified as needing corrective action? These land use changes may 

necessitate revisions to the corrective action schedule, e.g., to implement corrective action on 

some improperly abandoned artificial penetrations before the planned changes to land 

ownership take place. 

Step 2: Discuss the results with the UIC Program Director. EPA recommends that the owner or 

operator and the UIC Program Director discuss whether an amendment to the AoR and 

Corrective Action Plan is needed, based on the considerations in Step 1. The final decision 

regarding the need for an amended plan will be made by the UIC Program Director. 

If a review of the AoR delineation or other project data indicates that an amendment to the AoR 

and Corrective Action Plan is needed, it is important that the owner or operator begin revising 

the plan as soon as practical and coordinate this revision with review of the Testing and 

Monitoring Plan and the Emergency and Remedial Response Plan, so that the one (1) year 

deadline for amending those plans can be met. Regardless of whether a conversation with the 

UIC Program Director takes place, it is recommended that the owner or operator use the sitespecific monitoring and operational data to prepare and present a recommendation for action on 

an amended AoR and Corrective Action Plan.

If, based on a review of all available data and information, no amendment is needed, the owner 

or operator must continue to implement the existing approved AoR and Corrective Action Plan, 

i.e., continue any phased corrective action as described in the approved schedule and perform 

AoR reevaluations as planned. 
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Step 3: Amend the AoR and Corrective Action Plan if needed. EPA recommends that the 

amended AoR and Corrective Action Plan include the same categories of information that were

included in the original plan developed before injection commenced (see Section 2.1 of this 

guidance document for a description of the required plan elements). After injection has begun, 

and as new operational and monitoring data become available, the following changes may

necessitate an amendment to the plan: 

• Based on a comparison of previous modeling results and monitoring data, revisions may be 

required for the AoR modeling approach and can include justified modifications to the code 

used, parameterization process, assumptions (e.g., relative permeability/saturation 

relationship), or the representation of site-specific geologic conditions in the model; 

• If the predicted extent of the AoR changes, additional improperly plugged wells may be 

located within the newly defined AoR boundary. Likewise, if the plume and pressure front 

are moving at a faster rate than originally predicted (as evidenced through monitoring data or 

modeling), revisions to the phasing schedule for corrective action activities may be needed; 

• Information about when the next AoR reevaluation will be performed, or confirmation that 

the next scheduled reevaluation is appropriate, versus identifying the conditions that would 

warrant an AoR reevaluation ahead of schedule; or

• Any newly developed procedure that was not in the approved plan should be described in the 

amended plan and be submitted for the UIC Program Director’s approval. 

Step 4: Submit the amended plan. The Class VI Rule requires that the owner or operator submit 

the amended AoR and Corrective Action Plan to the UIC Program Director for approval 

following an AoR reevaluation or any other event that triggers an AoR and Corrective Action 

Plan Review [40 CFR 146.84(e)]. EPA recommends that owners or operators submit the revised 

AoR and Corrective Action Plan along with revisions to the Testing and Monitoring Plan and the 

Emergency and Remedial Response Plan, both of which are due within one (1) year of an AoR 

reevaluation or after any other event that triggers a revision of those plans. 

The amended plan must be approved by the UIC Program Director and would then be 

incorporated into their Class VI permit [40 CFR 146.84(e)(4)]. If changes to the AoR and 

Corrective Action Plan are needed, the UIC Program Director may need to modify the Class VI

permit. A permit modification under 40 CFR 144.39 (e.g., to incorporate a larger AoR or a larger

number of wells needing corrective action) would require notification to the public and an 

opportunity for public participation and comment. See 40 CFR Part 124 for the details of the 

process. Minor changes to the plan, as defined under 40 CFR 144.41 (e.g., to provide 

clarification, correct typographical errors, or other minor changes), do not require a permit 

modification or a public process under 40 CFR Part 124. See the Draft UIC Program Class VI

Implementation Manual, available on EPA’s website, for additional information about the 

procedures for modifying Class VI permits and the related plan amendments. 

3.0 Testing and Monitoring Plan

Testing and monitoring are important components of managing a GS project to ensure that 

USDWs are not endangered. Information generated through a rigorous testing and monitoring 

regime can provide information about site performance (e.g., the behavior and extent of the 
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Development Guidance 

carbon dioxide plume and pressure front) when compared to baseline site characterization

information submitted prior to injection or to any previously collected monitoring results.

Monitoring data can also be used to demonstrate that the project is performing as predicted, or 

provide warning that unexpected fluid movement has occurred and that USDWs may be 

endangered. For example, monitoring data can demonstrate that the carbon dioxide is confined in 

the injection zone as predicted; identify the potential corrosion of well construction materials and 

signal needed construction/mechanical integrity fixes; or identify changes in formation fluid 

geochemistry (e.g., pH decreases that could cause metals to leach into the ground water). 

Appropriate monitoring of a GS site can also provide data to maintain the efficiency of the 

storage operation, minimize costs, provide input data for AoR reevaluation modeling, or target 

future corrective action.

3.1 Developing the Testing and Monitoring Plan 

The Class VI Rule, at 40 CFR 146.90, describes the required elements of a Testing and 

Monitoring Plan, including: injectate analysis, monitoring the injection operation, corrosion 

monitoring, monitoring of geochemical changes in the subsurface, mechanical integrity tests 

(MITs), pressure fall-off testing, tracking the carbon dioxide plume and area of elevated 

pressure, surface air and/or soil gas monitoring for carbon dioxide fluctuations (at the discretion 

of the UIC Program Director), and any additional tests determined by the UIC Program Director

to be necessary to ensure protection of USDWs from endangerment. 

Guidance presenting recommended approaches to performing the activities under the approved 

Testing and Monitoring Plan (e.g., how to select appropriate testing equipment, monitoring 

techniques, locations, and frequencies) can be found in the Draft UIC Program Class VI Well 

Testing and Monitoring Guidance posted on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm. Exhibit 3 presents highlights 

of the information presented in that guidance. 

The Testing and Monitoring Plan must be submitted with the Class VI permit application for 

approval by the UIC Program Director [40 CFR 146.82(a)(15)]. It must include a description of 

how the owner or operator will meet the requirements of 40 CFR 146.90, including quality 

assurance and surveillance measures, and obtaining necessary access to sites for all testing and 

monitoring during the life of the GS project. The Testing and Monitoring Plan should be sitespecific and reflect the unique properties of the proposed site to ensure that early warning of 

USDW endangerment is provided.

The Sections below present the required elements of the Testing and Monitoring Plan, how they 

may be described to demonstrate to the UIC Program Director’s satisfaction that the plan is 

sufficient and can be approved, and the issues that owners or operators may consider as they 

develop their plan. Some of the elements of the Testing and Monitoring Plan are highly sitespecific (e.g., monitoring well placement) and will require detailed descriptions of how these 

specific factors were identified and considered in developing the plan. Other elements of the 

Testing and Monitoring Plan (e.g., where testing frequency is set in the Rule) may require less 

site-specific consideration and description. Appendix B of this guidance document presents a 

sample template of a Testing and Monitoring Plan.
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Exhibit 3: Draft UIC Program Class VI Well Testing and Monitoring Guidance Highlights

The Draft UIC Program Class VI Well Testing and Monitoring Guidance presents recommended approaches for 

performing the monitoring and testing activities required of Class VI well owners or operators during the lifetime of 

a GS project. 

The introductory Section reviews the Class VI regulations related to testing and monitoring. Remaining Sections of 

the guidance address the following topics:

• Performance of internal and external mechanical integrity tests during operation;

• Conducting operational testing and monitoring during injection; 

• Ground water monitoring and geochemical monitoring above the confining zone(s); 

• Tracking of the carbon dioxide plume and pressure front; and

• Monitoring of surface air and/or soil gas around the injection site.

For each Section, the guidance:

• Presents recommended ways to perform activities necessary to comply with Class VI Rule testing and 

monitoring requirements (e.g., ground water monitoring, MITs). 

• Provides references to other, more comprehensive, reference documents and published scientific literature for 

further information.

• Explains how and when to report to EPA the results of activities related to testing and monitoring and all 

relevant information that the UIC Program Director may evaluate.

3.1.1 Analysis of the carbon dioxide stream 

The Class VI Rule requires owners or operators to analyze the carbon dioxide stream with 

“sufficient frequency to yield data representative of its chemical and physical characteristics” [40 

CFR 146.90(a)]. Chemical characteristics include the fluid composition (e.g., the concentration 

of impurities in the carbon dioxide). Physical characteristics include temperature and pressure. 

The Draft UIC Program Class VI Well Testing and Monitoring Guidance provides detailed 

information and recommended approaches on performing analyses of various physical and 

chemical parameters of carbon dioxide streams. 

EPA recommends that the Testing and Monitoring Plan describe parameters and the frequencies 

at which they will be tested, and that the Plan specify, for each analyte/parameter, sampling 

methods; the analytical technique to be used; whether the testing will be done in-house or at a 

laboratory; and quality assurance and surveillance measures. To demonstrate that the proposed 

analysis will be performed at an appropriate frequency, the schedule may include testing dates as 

appropriate (e.g., the first day of each quarter or month), and describe how the test results are to 

be recorded and reported to the UIC Program Director. 

The necessary type and frequency of injectate analysis will be project-specific and will depend 

on the carbon dioxide source and the likelihood of variability in injectate composition. EPA 

recommends that the owner or operator consider and include the following in developing the 

Testing and Monitoring Plan:
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Development Guidance 

• The source of the carbon dioxide: it is important that the suite of parameters tested 

reflect the potential for impurities, based on the process generating the carbon dioxide 

and the capture technologies. Note: if the presence or concentrations of impurities render 

the carbon dioxide a hazardous waste, the injection well would need to be permitted as a 

Class I hazardous waste injection well. 

• Whether the source of the carbon dioxide will vary over the life of the well: for 

example, a carbon dioxide-capture process from a coal-fired power plant with a 

consistent coal source and operating parameters is likely to produce a carbon dioxide 

stream with a fairly consistent composition. Frequent changes in the carbon dioxide 

source, or multiple carbon dioxide sources, may necessitate more frequent or varied 

analysis that aligns to changes in the source facility or may necessitate testing and 

monitoring for additional parameters. 

• The potential for changes in the composition of the carbon dioxide stream based on 

contamination during transport (i.e., within a pipeline), including any mixing with water. 

3.1.2 Installation and use of continuous recording devices 

Owners or operators of Class VI wells must install and use continuous recording devices to 

monitor: injection pressure, injection rate, and volume of fluid injected; the pressure on the 

annulus between the tubing and the long-string casing; and the annulus fluid volume added [40 

CFR 146.90(b)]. Continuously monitoring these parameters (required in lieu of internal MITs) 

helps to verify that the well has internal mechanical integrity and ensure that the injection facility

is operating within permitted limits so as to not fracture the confining zone(s). These data can 

also serve as inputs for modeling to support AoR reevaluations. See the Draft UIC Program 

Class VI Testing and Monitoring Guidance at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm for descriptions of the types of 

gauges and meters available for use when monitoring these types of parameters. 

In the Testing and Monitoring Plan, EPA recommends that owners or operators describe the 

recording devices to be used for continuous monitoring, as well as the associated quality 

assurance and surveillance measures, the frequency at which the information will be recorded 

(e.g., every 20 seconds), and how the data will be retained and reported to comply with the 

reporting and recordkeeping requirements at 40 CFR 146.91. 

3.1.3 Corrosion monitoring 

The Class VI Rule requires owners or operators to monitor the injection well materials for signs 

of corrosion, including loss of mass, thickness, cracking, pitting, and other signs of corrosion [40 

CFR 146.90(c)]. This corrosion monitoring must be performed on a quarterly basis. Corrosion 

monitoring is necessary to verify that the well components meet the minimum standards for 

material strength and performance, and to identify well maintenance needs. Corrosion of well 

construction materials is a particular concern for Class VI wells given that carbon dioxide in the 

presence of water becomes acidic, potentially accelerating the corrosion of construction 

materials. The carbon dioxide stream for a GS project may also contain small volumes of 

impurities (e.g., sulfur dioxide) that could contribute to corrosion. 
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Class VI well operators can meet the Class VI Rule corrosion monitoring requirement by 

analyzing coupons of the well construction materials that are placed in contact with the carbon 

dioxide stream or by routing the carbon dioxide stream through a loop constructed of the 

material used in the well and inspecting the materials in the loop. Owners or operators may also 

use an alternative method, if it is approved by the UIC Program Director. See the Draft UIC 

Program Class VI Well Testing and Monitoring Guidance for additional information on 

corrosion testing methods. 

EPA recommends that the Testing and Monitoring Plan describe the corrosion monitoring 

program, including the monitoring method to be used and any associated quality assurance and 

surveillance measures. If the owner or operator seeks to use an alternative corrosion testing 

method, the Testing and Monitoring Plan should describe the method to be used and why it is 

appropriate for the project, e.g., to the specific injectate or the well characteristics. The owner or 

operator must discuss with the UIC Program Director the appropriateness of alternative methods 

as the plan is developed [40 CFR 146.90(c)(3)]. EPA recommends that the Testing and 

Monitoring Plan also include a schedule for performing the quarterly tests (e.g., anticipated 

testing dates) and how the data will be reported. 

3.1.4 Ground water quality monitoring 

Owners or operators must perform periodic monitoring of ground water quality and geochemical 

changes above the confining zone(s) [40 CFR 146.90(d)]; EPA recommends that this monitoring 

also include USDWs. This monitoring is important for identifying any geochemical changes that 

may be a result of fluid movement through the confining zone(s) and/or any fluid movement into 

USDWs, including whether formation fluids have acidified and might have leached (or may 

leach in the future) metals into the ground water. 

Site characterization data (particularly baseline geochemical data) should be considered in 

selecting ground water monitoring parameters, and ground water monitoring data should be 

compared to the initial data collected during site characterization. See the Draft UIC Program 

Class VI Well Site Characterization Guidance for suggestions about what information must be 

generated as part of the baseline data collection required under 40 CFR 146.82(a). The location 

and number of monitoring wells must be based on specific information about the GS project, 

including site-specific geology and baseline geochemistry, the presence of artificial penetrations, 

and planned operations (carbon dioxide injection rates and volumes).

Where injection depth waivers are sought, the plan must also describe the ground water quality 

monitoring that will be done below the lower confining zone, e.g., in the first USDW below the 

lower confining zone. See the Draft UIC Program Class VI Well Injection Depth Waivers 

Guidance for additional monitoring considerations for wells operating under injection depth 

waivers. See the Draft UIC Program Class VI Well Testing and Monitoring Guidance for 

additional information on ground water monitoring, including analytical methods and monitoring 

well design.

It is recommended that the Testing and Monitoring Plan describe the number and placement of 

monitoring wells, the parameters to be monitored, and the frequency at which sampling and 

analysis will be performed. EPA also recommends that the plan include maps that identify the 
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Development Guidance 

injection well, the AoR, and the placement of all planned monitoring wells. Ground water quality 

monitoring is site-specific and depends on many factors; considerations for each of these aspects 

of the Testing and Monitoring Plan are described below. 

Monitoring Well Placement 

Planning of monitoring well placement should include the number of wells, their distribution 

within the AoR, and their depth; the subsurface formations to be sampled; and the screened 

interval(s). The Testing and Monitoring Plan should identify (e.g., with the use of maps and 

cross sections) the location and depth of each monitoring well. The owner or operator must also 

indicate in the plan that they will be able to access (e.g., have rights to drill and sample the 

ground water) all planned monitoring well locations.

EPA recommends that owners or operators consider the installation and operation of more than 

the minimally acceptable number of monitoring wells. For example, owners or operators may 

consider and discuss with the UIC Program Director what monitoring may be needed—not only 

in the near term, but also during the period of active injection operations (i.e., as the injected 

carbon dioxide is moving away from the well). More extensive and frequent monitoring from the 

outset of the injection operation may eliminate the need for future amendments to the Testing 

and Monitoring Plan or to the permit. This more extensive and frequent monitoring throughout 

the injection phase may also support more dependable non-endangerment demonstrations during 

the post injection site care (PISC) phase of a GS project (see Section 5 of this guidance 

document). 

EPA recommends that owners or operators consider the tradeoff between a monitoring program 

with a large number of monitoring wells versus a minimum number of wells, based on sitespecific geologic conditions and the subsurface impacts of drilling monitoring wells. An 

extensive monitoring program involving many monitoring wells could better characterize

changes in subsurface geochemistry and more closely track the carbon dioxide plume; however, 

with a larger number of wells, there is an increased chance that one or more wells could serve as 

a conduit for fluid movement into USDWs. Where possible, owners or operators may consider 

using monitoring wells for multiple purposes, such as ground water monitoring above the 

confining zone and pressure monitoring in the injection zone, to satisfy the requirements at 40 

CFR 146.90(g); see Section 3.1.7 of this guidance document. While wells with multiple 

screenings (i.e., in the injection and confining zones) may be more expensive to construct, this 

multiple usage of a single monitoring well may ultimately reduce costs. Appropriate design 

specifications for wells with multiple screenings in different zones are provided in the Draft UIC 

Program Class VI Well Testing and Monitoring Guidance. 

Existing wells in the AoR may be considered for use as monitoring wells. Enhanced oil or gas 

recovery fields, for example, might contain existing production or monitoring wells that could be 

adapted for use as monitoring wells instead of being plugged. 

It is important that monitoring wells be properly designed and constructed in order to reduce 

their potential to serve as conduits for fluid movement into USDWs. This is particularly 

important where the monitoring wells perforate the confining zone (e.g., to allow pressure 
UIC Program Class VI Well Project Plan 29 August 2012

Development Guidance 

monitoring in the injection zone or to sample ground water below the lower confining zone for 

wells operating under injection depth waivers). EPA recommends that the Testing and 

Monitoring Plan include schematics of the planned monitoring wells, including the sampling 

equipment the owner or operator plans to use. The Draft UIC Program Class VI Well Testing 

and Monitoring Guidance provides additional information on monitoring well construction. 

Monitoring wells that are not used to inject carbon dioxide are not Class VI wells and do not 

need to have all of the project plans that are required for Class VI wells. However, drilling these 

wells may require a state permit, so owners or operators should confer with appropriate state 

permitting authorities to confirm what state requirements apply. EPA clarifies that the 

monitoring well is part of the Testing and Monitoring Plan, which must be approved by the UIC 

Program Director.

The location, number, and depth of monitoring wells must be based on site-specific information 

about the project [40 CFR 146.90(d)(1)]. See the Draft UIC Program Class VI Well Testing and 

Monitoring Guidance for additional information on proper well spacing. The Testing and 

Monitoring Plan must describe how the following information has been considered in 

determining appropriate monitoring well placement [40 CFR 146.90(d)(1)]: 

• The depth, thickness, and permeability of the injection and confining zones, 

USDWs, and any relevant additional zones; 

• The size and shape of the AoR, based on the current delineation; 

• The presence of artificial penetrations; and

• The planned injection rates and volumes. 

Other site-specific considerations the owner or operator may consider in planning monitoring 

well placement include: 

• Land use changes in the region and the pace of development, including the presence 

of sensitive populations such as children and environmental justice concerns, which 

may warrant additional monitoring to address public concerns. EPA recommends that 

owners or operators work with the UIC Program Director on any issues pertaining to 

environmental justice concerns and sensitive populations, as the UIC Program 

Director may have additional tools and resources to assist in this process; 

• Proximity to USDWs, public water supplies, or private wells, which may 

necessitate additional monitoring, particularly if all residents in the vicinity of the 

well rely on one USDW for their drinking water supply; 

• The presence of other injection operations, which may impact geochemical 

changes in formation fluids or subsurface fluid movement; and

• The possibility of conducting water quality monitoring in the injection zone using 

wells needed for pressure monitoring (i.e., monitoring for the presence or absence 

of elevated pressure) [40 CFR 146.90(g)]. See Section 3.1.7 of this guidance 

document for more information. 
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Development Guidance 

Monitoring Parameters 

Determining the ground water monitoring parameters to be analyzed is site-specific. EPA 

expects that ground water collected above the confining zone, or from any additional zones, 

would most likely be monitored for, at a minimum, carbon dioxide species; total dissolved solids 

(TDS); specific conductivity (SC); temperature; potential for hydrogen ions (pH), i.e., a measure 

of water acidity; and carbon dioxide. In addition, based on site-specific considerations, owners or 

operators may also monitor for major anions and cations; trace metals (e.g., arsenic, mercury, or 

lead); carbon dioxide tracers; hydrocarbons; and volatile organic compounds (VOCs). EPA 

suggests that the choice of monitoring parameters be based on the baseline geochemical data 

collected during the initial site characterization, all previous monitoring data, and any available 

geochemical modeling information. 

To satisfy the UIC Program Director that the plan is approvable, the Testing and Monitoring Plan 

should describe the specific parameters to be monitored and detail any additional factors that 

were considered in developing the list of monitoring parameters. In addition, EPA recommends 

that the planned sample collection, handling (i.e., chain of custody), and analytical procedures be 

provided; the plan should also describe the analytical methods and the name of the certified 

laboratory that will perform the analysis. The Draft UIC Program Class VI Well Testing and 

Monitoring Guidance describes examples of acceptable sampling procedures for ground water 

monitoring at GS sites. 

EPA recommends that owners or operators consider and convey to the UIC Program Director the 

following in determining which geochemical parameters to include in the Testing and 

Monitoring Plan: 

• If any impurities are present (or may be anticipated to be present) in the carbon dioxide 

stream (e.g., hydrogen sulfide) because it is important that these be included in routine 

ground water monitoring; 

• The type of target formation; for example, EPA recommends that owners or operators 

of GS projects located in depleted (or depleting) oil and gas reservoirs monitor for 

residual hydrocarbons that may be in the formation and potentially mobilized into ground 

water as a result of carbon dioxide injection; and

• If site-specific data generated during the baseline geochemical survey indicate the 

presence of arsenic or other metals that have the potential to be mobilized by the 

injection activity, it may be appropriate to monitor for heavy metals, organic 

contaminants, and dissolved minerals. 

Monitoring Frequency 

EPA recommends that the Testing and Monitoring Plan describe, for each monitoring parameter, 

the proposed frequency of sampling and analysis. Testing for more typical parameters, such as

TDS, aqueous and pure carbon dioxide, and pH will likely occur relatively frequently, while 

parameters less likely to occur in ground water may warrant less frequent analysis. 
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Development Guidance 

The Class VI Rule requires that the owner or operator consider baseline geochemical data and 

AoR modeling results in determining the monitoring frequency [40 CFR 146.90(d)(2)]. Thus, the 

Testing and Monitoring Plan must describe how these factors were considered. EPA 

recommends that owners or operators also consider the schedule for planned AoR reevaluations, 

so that the ground water monitoring data are available to serve as inputs for future modeling 

runs, if necessary. 

3.1.5 A demonstration of external mechanical integrity

Owners or operators of GS projects must perform external MITs to determine the absence of 

significant fluid movement into a USDW through potential channels adjacent to the injection 

well bore [40 CFR 146.90(e)]. Regular MITs are an important protective measure that can 

indicate the need for well repairs in order to avoid potential contamination through the well bore. 

The Class VI Rule, at 40 CFR 146.89(c), specifies the approved MIT methods for Class VI

wells: an approved tracer survey, such as an oxygen-activation log, or a temperature or noise log. 

Other MIT methods may be approved by the EPA Administrator. However, a request for using 

alternative methods other than those currently approved by EPA requires an additional EPA 

approval process to become acceptable and the eventual publication of the alternative method 

approval in the Federal Register, as required at 40 CFR 146.89(e). Therefore, EPA recommends 

that owners or operators discuss any such need for an alternative MIT method with the UIC 

Program Director as early as possible to determine what course of action may be preferred to 

avoid delays in approving the Testing and Monitoring Plan.

Note that periodic internal MITs are not required for Class VI injection wells. The continuous 

monitoring that is briefly described in Section 3.1.2 of this guidance document is required to be 

performed in lieu of internal MITs during injection operations. However, internal MITs must still 

be performed before commencing injection and before plugging the well [40 CFR 146.82(c)(8) 

and 146.92(a)]. 

Selecting the specific MITs to be used at an injection well should be based on the well design 

and the planned use of automatic surface or down-hole shut off devices [40 CFR 146.88(e)(2) 

and 146.88(e)(3)]. See the Draft UIC Program Class VI Well Testing and Monitoring Guidance

for additional information on available MITs. See Section 2 of the Draft UIC Program Class VI

Well Construction Guidance for additional information on using surface and down-hole shut off 

devices. 

The UIC Program Director has the discretion to require the use of casing inspection logs to 

determine if there is any casing corrosion [40 CFR 146.89(d)]. The frequency of this casing 

corrosion test is established based on site-specific and well-specific conditions, and EPA 

recommends that this information be incorporated into the Testing and Monitoring Plan. See 

Section 3.1.3 for additional information on other types of corrosion monitoring. 

External MITs must be performed at least once per year. However, the owner or operator may set 

the testing schedule to coincide with regularly scheduled well workovers or other routine well 

maintenance. EPA recommends that the plan describe the specific MITs to be employed, the 
UIC Program Class VI Well Project Plan 32 August 2012

Development Guidance 

associated quality assurance and surveillance measures, anticipated testing dates, and the 

owner’s or operator’s plans to record and report the MIT results.

3.1.6 A pressure fall-off test

Pressure fall-off tests are designed to verify that pressure declines agree with modeled 

projections of reservoir pressure changes, in addition to providing information about formation 

characteristics (e.g., transmissivity and injectivity). A pressure fall-off test must be performed 

every five (5) years, unless more frequent testing is required by the UIC Program Director [40 

CFR 146.90(f)]. However, the owner or operator may set the testing schedule to coincide with 

scheduled well workovers or other testing or maintenance. EPA recommends that the owner or 

operator and the UIC Program Director discuss what conditions may trigger the need for more 

frequent pressure fall-off testing. See the Draft UIC Program Class VI Well Testing and 

Monitoring Guidance for additional information about performing pressure fall-off tests. 

EPA recommends that the Testing and Monitoring Plan describe the pressure fall-off tests to be 

employed, the associated quality assurance and surveillance measures, anticipated testing dates, 

and how the owner or operator plans to record and report the results. 

3.1.7 Carbon dioxide plume and pressure front tracking 

Owners or operators must perform testing and monitoring to track the extent of the carbon 

dioxide plume and the presence or absence of elevated pressure, i.e., the pressure front [40 CFR 

146.90(g)]. This monitoring provides information about the rate and direction of carbon dioxide 

plume and pressure front movement, demonstrates that formation pressures are stable, and 

verifies that the injectate is safely confined (or provides early warning that it is not). 

The purpose of this requirement is to ensure that the owner or operator and the UIC Program 

Director know, and discuss, the position of the carbon dioxide plume and pressure front during 

the lifetime of the GS project. This is necessary to ensure that carbon dioxide and/or mobilized 

formation fluids are not endangering USDWs or migrating in a manner contrary to the initial 

estimates generated by the AoR delineation modeling. Ongoing monitoring data must also be 

used to inform AoR reevaluations. 

All owners or operators must use direct methods to monitor the pressure front and determine the 

presence or absence of elevated pressure in the injection zone [40 CFR 146.90(g)(1)]. Owners or 

operators may also find it useful to perform pressure monitoring in ground water quality 

monitoring wells (i.e., in the first permeable formation above the confining zone). This could 

provide additional data to verify confinement without the construction of additional monitoring 

wells. See Section 3.1.4 of this guidance document for additional information on the use and 

benefits of multiple-purpose monitoring wells. 

Class VI injection well owners or operators must use indirect methods (e.g., seismic, electrical, 

gravity, or electromagnetic surveys) to track the carbon dioxide plume, unless the UIC Program 

Director determines, based on the site-specific geology, that such indirect methods are not 

feasible [40 CFR 146.90(g)(2)]. If indirect geophysical techniques cannot be used to track the 
UIC Program Class VI Well Project Plan 33 August 2012

Development Guidance 

plume at a sufficient resolution, the UIC Program Director may require direct geochemical 

sampling for tracking of the carbon dioxide plume in the injection zone. 

Various subsurface indirect monitoring techniques are available to track the extent of a carbon 

dioxide plume, including seismic and electrical methods. EPA recommends that the owner or 

operator discuss with the UIC Program Director the use and feasibility of indirect geophysical 

methods, including which methods are most appropriate based on site-specific geologic 

information. If the owner or operator believes that no indirect plume tracking methods are 

feasible, it is important that this be discussed with the UIC Program Director early in the 

planning process. The Draft UIC Program Class VI Well Testing and Monitoring Guidance 

provides detailed information on carbon dioxide plume and pressure front tracking methods. 

The Testing and Monitoring Plan must describe which direct and indirect tracking methods will 

be used. This might include pressure monitoring locations, the types of indirect surveys to be 

performed, their resolution, and the areal extent of geophysical surveys. The associated quality 

assurance and surveillance measures must also be included in the plan. It is important that the 

plan describe the testing frequency, how site access will be guaranteed, and how the owner or 

operator plans to record and report the results. 

EPA recommends that owners or operators consider and include the following in developing the 

plan for carbon dioxide plume and pressure front tracking: 

• The predicted size and shape of the AoR, which would affect the pressure monitoring 

locations and the areal extent of geophysical surveys; 

• Any site-specific geologic conditions that inform what indirect geophysical techniques 

may be used, including the presence of any features that may impact the feasibility of 

geophysical methods; 

• The presence of multiple subsurface layers that are defined as USDWs, which may 

affect the placement of pressure monitoring wells; 

• Whether an injection depth waiver is sought. This would necessitate additional 

geochemical monitoring or pressure monitoring, both above the upper confining zone and 

below the lower confining zone; 

• The presence of other injection operations, which may impact pressure changes in the 

subsurface; and

• The presence, location, and construction of any additional wells at the site, including 

monitoring wells, which may be used for plume and pressure-front tracking.

3.1.8 Surface air and/or soil gas monitoring (if required) 

The Class VI Rule provides the UIC Program Director discretion to require surface air and/or 

soil gas monitoring to detect movement of carbon dioxide that could endanger a USDW [40 CFR 

146.90(h)]. All surface air and/or soil gas monitoring must be based on potential risks to USDWs 

within the AoR. 

The UIC Program Director's decision to require surface air and/or soil gas monitoring and the 

selection of monitoring methods will be site-specific (e.g., based on geology or injection depth). 
UIC Program Class VI Well Project Plan 34 August 2012

Development Guidance 

Therefore, it is important that the owner or operator and UIC Program Director discuss the 

proposed Testing and Monitoring Plan and the site characterization data collected as the plan is 

developed. This dialogue can support a UIC Program Director’s determination as to whether any 

surface air and/or soil gas monitoring is necessary to protect USDWs from endangerment. The 

owner or operator should consider what baseline surface air and/or soil gas monitoring data may 

need to be collected prior to the commencement of injection activities. 

If the UIC Program Director requires the installation and use of surface air and/or soil gas 

monitoring technologies, Class VI well owners or operators may demonstrate that monitoring 

employed under Subpart RR of the Greenhouse Gas Reporting Program [40 CFR 98.440 to 

98.449] meets the requirements of the Class VI Rule at 40 CFR 146.90(h)(3). Where the UIC 

Program Director approves the use of monitoring employed under Subpart RR, Class VI well 

owners or operators may use the same technologies as they will employ to comply with Subpart 

RR and present this as part of the Testing and Monitoring Plan. Compliance with these 40 CFR 

Part 98 requirements is considered a condition of the Class VI permit if surface air and/or soil 

gas monitoring is required by the UIC Program Director [40 CFR 146.90(h)(3)], and the UIC 

Program Director approves the use of monitoring employed under Subpart RR. 

If surface air and/or soil gas monitoring is determined by the UIC Program Director to be 

necessary, then the owner’s or operator's Testing and Monitoring Plan must describe how the 

proposed monitoring will yield useful information for the AoR delineation and/or for compliance 

with standards that prevent movement of fluids to USDWs under 40 CFR 144.12 [40 CFR 

146.90(h)(2)]. The Testing and Monitoring Plan must also describe the carbon dioxide 

monitoring techniques and equipment, quality assurance and surveillance measures, monitoring 

locations (including how the owner or operator will access the monitoring sites), monitoring 

frequency (e.g., anticipated dates), and how the owner or operator plans to record and report the 

results. See the Draft UIC Program Class VI Well Testing and Monitoring Guidance for 

additional information on surface air and/or soil gas monitoring technologies. The owner or 

operator should also consider the requirements of 40 CFR Part 98 when developing this 

particular aspect of the Testing and Monitoring Plan. 

The Subpart RR General Technical Support Document (TSD) provides additional technical 

information on the required testing and monitoring under Subpart RR. A copy of the Subpart RR 

TSD is available at http://www.epa.gov/climatechange/emissions/downloads10/Subpart-RRUU_TSD.pdf. For additional information on Subpart RR under 40 CFR Part 98, see 

http://www.epa.gov/climatechange/emissions/subpart/rr.html. 

EPA recommends that the owner or operator and the UIC Program Director discuss and consider 

the following in determining whether surface air and/or soil gas monitoring is needed or when 

developing the plan: 

• The presence or proximity of USDWs that could be endangered, which will drive the 

need for this monitoring; 

• Baseline geologic information regarding the existence and location of any fractures, 

faults, or other discontinuities that could serve as conduits for fluid and/or gas movement; 

• Baseline geochemical data (e.g., background natural carbon dioxide concentrations); 
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Development Guidance 

• The pace of development or land use changes in the region, which would drive 

monitoring locations (e.g., the need to monitor near structures or populated areas); and

• Public input and concerns, including environmental justice considerations. A robust 

monitoring scheme that includes surface air and/or soil gas monitoring for carbon dioxide 

may be one component of local acceptance of the project.

3.1.9 Any additional monitoring required by the UIC Program Director 

The Class VI Rule provides the UIC Program Director discretion to require the owner or 

operator to perform any additional monitoring necessary to support, upgrade, and improve 

computational modeling of the AoR, and to determine compliance with standards that prevent 

movement of fluids into USDWs [40 CFR 146.90(i)]. 

Another monitoring technique that may be applicable at a GS project is the use of tracers. These 

may include stable isotopes of carbon and oxygen, perfluorocarbon, or radioactive tracers. 

Tracers can be useful tools for monitoring, plume tracking, and verification at GS sites and may 

help improve public confidence in certain projects. However, tracer use is not appropriate in all 

situations. For this reason, they are not required at all GS sites, although the UIC Program 

Director has the discretion to require their use if he/she determines that using tracers is necessary 

to support, upgrade, and improve computational modeling of the AoR required under 40 CFR 

146.84(c) or to determine compliance with standards under 40 CFR 144.12. Another example of 

additional monitoring is, based on the results of indirect methods, using direct methods for 

geochemical sampling for tracking of the carbon dioxide plume in the injection zone (see Section 

3.1.7). 

EPA recommends that, while developing the plan, the owner or operator discuss the proposed 

Testing and Monitoring Plan and the site characterization data collection process with the UIC 

Program Director in order to determine whether any additional monitoring would be necessary at 

the proposed Class VI injection well site. If the UIC Program Director requires additional testing 

and monitoring, the plan must describe the testing techniques, equipment to be used and the 

associated quality assurance and surveillance measures, testing frequency (e.g., anticipated test 

dates), and how the owner or operator plans to record and report the results [40 CFR 146.90]. 

3.2 UIC Program Director’s Evaluation of the Testing and Monitoring Plan 

The UIC Program Director must evaluate the proposed Testing and Monitoring Plan, along with 

the geologic and proposed operating data submitted with the Class VI permit application, to 

determine whether to approve the plan. Therefore, the owner or operator must demonstrate, to 

the satisfaction of the UIC Program Director, that the proposed plan will be sufficient to meet the 

requirements of 40 CFR 146.90 and account for all site-specific conditions to ensure that 

USDWs are protected from endangerment. For example, the UIC Program Director may consider

the following: 

• Is the planned testing and monitoring sufficiently robust (e.g., the proposed frequency, 

location, parameters) to provide early warning if USDWs are endangered or when emergency 

or remedial response is needed? 
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• Does the proposed Testing and Monitoring Plan address all potential risks identified in the 

site characterization process, e.g., all nearby USDWs or non-transmissive faults or fractures?

• Will the proposed plan provide the necessary data and model inputs on which to verify 

predictions of carbon dioxide plume movement and to reevaluate the AoR?

• Is monitoring appropriate to address the additional risk associated with injection into nonUSDWs that are below/between USDWs if an injection depth waiver is sought? 

• Are the planned monitoring wells located and constructed in a way to ensure that they do not 

provide a conduit for fluid movement to USDWs? 

The submittal, evaluation, and approval of the Testing and Monitoring Plan are meant to be parts 

of an iterative process. This may involve multiple drafts of the plan until all required information 

is submitted in an appropriate format and level of detail. If the UIC Program Director has reason 

to believe, based on site-specific conditions, that additional monitoring is needed to sufficiently 

assess the behavior of the GS project or to protect USDWs from endangerment, it is within 

his/her authority to request that additional monitoring be included. This may include more 

frequent monitoring or the monitoring of additional parameters. The approved Testing and 

Monitoring Plan is enforceable, whether or not it is a condition of the permit, because the plan 

itself and the UIC Program Director’s approval are required by the Class VI Rule [40 CFR 

146.90]. 

Interaction and conversation are encouraged to discuss the areas of UIC Program Director’s 

discretion, such as more frequent monitoring or surface air and/or soil gas monitoring. Having 

such discussions prior to developing and submitting the plan may increase the chance that the 

proposed plan can be approved, and it may avoid the need for plan revision or future 

amendments. 

Appendix F of this guidance document presents a checklist of questions and considerations that 

UIC Program Directors may use when evaluating the proposed Testing and Monitoring Plan and 

other GS project plans. See the Draft UIC Program Class VI Implementation Manual for 

additional information on how the UIC Program Director may evaluate the plan, including 

exercising any discretion regarding requiring additional monitoring. 

3.3 Amending the Testing and Monitoring Plan 

The Class VI Rule requires that the Testing and Monitoring Plan be reviewed and, if necessary, 

amended following each reevaluation of the AoR [40 CFR 146.90(j)]. The purpose of this review 

is to ensure that the management of the GS project and all of the project plans are based on the 

most up-to-date information available and continue to provide for the protection of USDWs from 

endangerment. This review of the plan follows the required AoR reevaluation timeframe, which 

must occur at least once every five (5) years. See Section 5 of the Draft UIC Program Class VI

Well AoR Evaluation and Corrective Action Guidance for additional information on performing 

AoR reevaluations. The amended Testing and Monitoring Plan (or a demonstration that no 

amendment is needed) is due no later than one (1) year after the reevaluation [40 CFR 

146.90(j)(1)].
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Development Guidance 

Owners or operators must use the results of the AoR reevaluation, along with monitoring data 

(e.g., the results of carbon dioxide plume and pressure front tracking and ground water 

monitoring); operational data (e.g., injection rates and volumes); and any newly acquired site 

characterization data collected since the last AoR reevaluation, to assess the need for amending 

the Testing and Monitoring Plan. The owner or operator must also review the plan if there are 

significant changes to GS facility operations, such as the addition of a Class VI injection well, or 

if any adverse events require the implementation of an emergency response. 

EPA recommends that the owner or operator and the UIC Program Director coordinate and 

discuss the most recent AoR evaluation, along with monitoring and operational data and other 

information about the facility during this plan review. EPA considers this dialogue to be an 

important part of the process to ensure that the GS project continues to be managed appropriately 

and that compliance with the Class VI permit is achieved. These discussions can also help the 

owner or operator to understand the UIC Program Director’s expectations, including whether an 

amended plan is needed, so that the UIC Program Director receives all the required information 

up front in order to facilitate the review process. 

The Sections below describe a recommended process by which the owner or operator may 

review and amend the Testing and Monitoring Plan.

Step 1: Review the results of the AoR reevaluation or relevant monitoring and operational 

data. The purpose of this review is to identify whether an amendment to the Testing and 

Monitoring Plan is needed. Topics that may be considered in the review include: 

• Carbon dioxide plume and pressure front monitoring data, e.g., any changes in the size or 

shape of the AoR or indications that the plume is moving differently than predicted. These 

changes may indicate the need for additional monitoring locations, pressure monitoring in 

more locations, or more frequent/extensive geophysical surveys. Since some variability is 

expected, the owner or operator is advised to evaluate the significance of these changes and 

discuss with the UIC Program Director the need for any additional testing and monitoring. 

• Evidence of leaching/mobilization of metals or organic constituents in the subsurface, which 

may indicate a need to modify ground water monitoring parameters or analytes. An analysis 

of the location of the subsurface reactions (i.e., in the injection zone) and the risks posed by

fluid movement that would require additional monitoring. 

• Model revisions: if the most recent AoR reevaluation necessitates a revision to the AoR 

computational model, EPA recommends that the Testing and Monitoring Plan be amended to 

reflect any changes to the prediction of plume and pressure front movement. 

• Well construction, mechanical integrity, and corrosion testing data, which may indicate the 

need to modify the well testing regime, e.g., by revising MITs or corrosion monitoring 

activities.

• The availability of new, more site-suitable, testing and monitoring methods. 

• If an expansion to the areal extent of an existing Class II enhanced recovery aquifer 

exemption was issued for the project, whether testing and monitoring data confirm that the 

estimated extent of the exemption is adequate. 
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Development Guidance 

Step 2: Discuss the results with the UIC Program Director. EPA recommends that the owner or 

operator and the UIC Program Director discuss whether an amendment to the Testing and 

Monitoring Plan is needed. If the AoR reevaluation and monitoring/operating data indicate that 

the plume is moving as predicted, an amendment may not be necessary. The final decision 

regarding the need for an amended plan will be made by the UIC Program Director. 

If a review of the AoR reevaluation or other project data indicate that an amendment to the plan 

is needed, then EPA recommends that work on revising the plan begin as soon as possible so that 

the one (1) year deadline for amending this plan (along with any related amendments to other 

project plans) can be met [40 CFR 146.90(j)(1)]. Regardless of whether a conversation with the 

UIC Program Director takes place, it is recommended that the owner or operator use the sitespecific monitoring and operational data to prepare and present a recommendation for action on 

an amended Testing and Monitoring Plan.

If, based on a review of all available data and information, no amendment is needed, the owner 

or operator must continue to monitor the well and the site as described in the existing approved 

Testing and Monitoring Plan. 

Step 3: Amend the Testing and Monitoring Plan if needed. EPA recommends that the amended

Testing and Monitoring Plan include the same categories of information that were required for 

the original plan that was developed before injection commenced (see Section 3.1 of this 

guidance document for a description of the required plan elements). The amended plan might 

incorporate the following (as appropriate): 

• Changes in monitoring/testing frequency, e.g., carbon dioxide stream analysis, ground water 

monitoring, and carbon dioxide plume and pressure front tracking; 

• New monitoring well locations; 

• Additional parameters for ground water testing; 

• Changes to indirect or direct plume tracking methods, scope, or frequency; 

• Additional MITs or corrosion monitoring; 

• The addition of surface air and/or soil gas monitoring determined to be needed to protect 

USDWs from endangerment; and

• Any newly developed testing or monitoring procedure that was not in the approved plan. 

Step 4: Submit the amended plan. The owner or operator must submit the amended plan to the 

UIC Program Director for approval within one (1) year of the AoR reevaluation or within one (1) 

year of any other event that triggers a Testing and Monitoring Plan review [40 CFR 146.90(j)(1)-

146.90(j)(3)]. The amended plan must be approved by the UIC Program Director and would then 

be incorporated into the Class VI permit. If changes to the plan are needed, the UIC Program 

Director may need to modify the Class VI permit. A permit modification under 40 CFR 144.39 

(e.g., to incorporate changes to the needed types of testing, additional monitoring locations, or 

new testing methods) would require an opportunity for public notification and comment. See 40 

CFR Part 124 for details on the public notice and comment process. Minor changes to the plan, 

as defined under 40 CFR 144.41 (e.g., to provide clarification, require more frequent ground 

water sampling, or correct typographical errors), do not require a permit modification or a public 

process under 40 CFR Part 124. See the Draft UIC Program Class VI Implementation Manual 
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Development Guidance 

for additional information about the procedures for modification of Class VI permits and the 

related plan amendments. 

4.0 Injection Well Plugging Plan

Improperly plugged injection wells have the potential to become conduits for fluid movement 

into USDWs. Therefore, developing, maintaining, and implementing an Injection Well Plugging 

plan is important to assuring that Class VI injection wells will be plugged properly, so as to not 

endanger USDWs following the cessation of injection. 

Owners or operators of other injection well types may be familiar with preparing an Injection 

Well Plugging Plan (also known as a plugging and abandonment plan), and EPA expects that 

developing an Injection Well Plugging Plan will involve a similar effort. However, because 

carbon dioxide in the presence of water has the potential to degrade the materials used to plug 

the injection well, the plugging of Class VI wells presents additional challenges that may not 

have been addressed in the course of plugging other classes of injection wells. 

4.1 Developing the Injection Well Plugging Plan 

The Class VI Rule, at 40 CFR 146.92(b), presents the required elements of an Injection Well 

Plugging Plan. Developing a plugging plan is also required of Class I and Class II injection well 

owners or operators. Many of the plugging procedures used by Class I and Class II well 

operators may be acceptable for Class VI injection wells. However, one important consideration 

is that Class VI injection wells must be plugged using methods and materials that are compatible 

with the carbon dioxide stream. Additionally, EPA recommends that, when selecting plugging 

materials and methods, the owner or operator consider the formation fluids and conditions to 

which the materials will be exposed. Therefore, the owner or operator must demonstrate, to the 

satisfaction of the UIC Program Director, that Class VI wells will be plugged in a manner that 

will resist degradation in the presence of carbon dioxide or carbonic acid. 

The Injection Well Plugging Plan must be submitted with the Class VI permit application for 

approval by the UIC Program Director [40 CFR 146.82(a)(16)], and must include a description 

of how the owner or operator will meet the Class VI injection well plugging requirements at 40 

CFR 146.92. 

Guidance on carrying out the approved plan (e.g., selection and emplacement of plugs and 

cement) is presented in the Draft UIC Program Class VI Well Plugging, PISC, and Site Closure 

Guidance. Exhibit 4 presents the highlights of that guidance document. 
UIC Program Class VI Well Project Plan 40 August 2012

Development Guidance 

Exhibit 4: Draft UIC Program Class VI Well Plugging, PISC, and Site Closure Guidance 

Highlights

The Draft UIC Program Class VI Well Plugging, PISC, and Site Closure Guidance provides information describing 

how to correctly plug and abandon injection wells, conduct PISC monitoring, and perform site closure activities. 

Furthermore, the guidance discusses under what conditions the PISC monitoring timeframe may be lengthened or 

shortened, how the owner or operator of a Class VI project will demonstrate to the UIC Program Director that the 

risks posed to USDWs have been reduced during the PISC phase, and how the owner or operator will demonstrate 

non-endangerment prior to site closure. 

The introductory Section reviews the various phases of a GS project, and the Class VI requirements pertaining to 

well plugging, PISC, and site closure. Remaining Sections of the guidance address the following topics:

• Injection and monitoring well plugging; 

• PISC monitoring; 

• Demonstration of an alternative post-injection site care timeframe;

• Demonstration of reduction of risks posed to USDWs;

• Demonstration of non-endangerment of USDWs; and

• Site closure. 

For each Section, the guidance:

• Explains various approaches to perform activities necessary to comply with well plugging, PISC, and site 

closure requirements. Illustrative examples are provided in several cases.

• Provides references to other, more comprehensive documents and published scientific literature for further 

information.

• Explains various approaches for how and when to report to the UIC Program Director the results of activities 

related to well plugging, PISC, and site closure.

The following information must be described, to the UIC Program Director’s satisfaction, in 

order to ensure that the planned injection well plugging activities are sufficient to protect 

USDWs from endangerment [40 CFR 146.92(b)]. Appendix C presents a sample template of an 

Injection Well Plugging Plan. 

 

• Appropriate tests or measures to determine bottom-hole reservoir pressure [40 CFR 

146.92(b)(1)]. The purpose of testing bottom-hole reservoir pressure is to determine the 

appropriate density of plugging fluids to achieve static equilibrium prior to plug placement; 

• Appropriate testing methods to ensure external mechanical integrity [40 CFR 146.92(b)(2)]. 

An external MIT is necessary to ensure that the long-string casing and cement that are left in 

the ground after the well is plugged will maintain their integrity over time. The Draft UIC 

Program Class VI Well Testing and Monitoring Guidance provides additional information on 

performing MITs; 

• The type and number of plugs to be used [40 CFR 146.92(b)(3)]; 

• The placement of each plug, including the elevation of the top and bottom of each plug [40 

CFR 146.92(b)(4)]. EPA recommends that the plan describe the placement of all plugs. 

Schematics and drawings may be appropriate to demonstrate this; 
UIC Program Class VI Well Project Plan 41 August 2012

Development Guidance 

• The type, grade, and quantity of material to be used in plugging [40 CFR 146.92(b)(5)]. EPA 

recommends that the plan demonstrate that the cement is appropriate to withstand contact 

with the carbon dioxide or acidified formation fluids; and 

• The method of plug placement, e.g., the balance method, retainer method, or two-plug 

method [40 CFR 146.92(b)(6)]. 

EPA recommends that the owner or operator consider the following when developing the 

Injection Well Plugging Plan: 

• The location and thickness of the lowermost injection zone and USDW-containing strata, 

which dictate the location of all plugs; 

• Well construction details, particularly the depth of the bottom of the intermediate and 

surface casings, which would affect the number of plugs and the types and amount of cement 

needed; 

• Types of subsurface formations penetrated by the well and their geochemistry, which may 

influence both plugging methods and the types of cement needed (for open-hole plugging). 

EPA recommends drilling out the casing before plugging the well to avoid the potential for 

the casing to corrode; 

• The composition of the carbon dioxide stream and formation fluid geochemistry, 

including any geochemical changes anticipated during the post-injection period, which can 

affect appropriate plugging and cementing materials; and

• If the well will operate under an injection depth waiver, EPA recommends that the 

Injection Well Plugging Plan describe any additional considerations to protect USDWs 

below the injection zone. 

4.2 UIC Program Director’s Evaluation of the Injection Well Plugging Plan 

The UIC Program Director must evaluate the owner’s or operator’s proposed Injection Well 

Plugging Plan, along with the geologic site characterization data, proposed construction plans, 

and proposed operating conditions that are submitted with the Class VI permit application. The 

owner or operator must demonstrate, to the satisfaction of the UIC Program Director, that the 

planned injection well plugging will prevent the well from serving as a conduit for fluid 

movement, particularly given the corrosiveness of carbon dioxide in the presence of water.

The UIC Program Director should evaluate the proposed Injection Well Plugging Plan to verify 

that all of the elements required in 40 CFR 146.92(b) are present, and that they account for all 

site-specific conditions to ensure that USDWs are protected from endangerment. For example, 

the UIC Program Director may evaluate the following: 

• Are the plugs and the cement that the owner or operator proposes to use appropriate for the 

injectate and formation fluid geochemistry, including any geochemical changes anticipated 

during the injection period? 

• Is the proposed placement of the plugs and cement appropriate based on the location of the 

injection zone, any production zones, any formations with USDWs, other geologic features, 

and the location of the bottom of the surface and intermediate casings? 
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• Is the proposed plugging plan appropriate to the planned construction of the well, e.g., to the 

sizes and depths of the various casing strings or the use of horizontal drilling techniques? 

• Are the proposed post-injection tests of the well (e.g., MITs and bottom-hole reservoir 

pressure tests) sufficient to characterize the well integrity and formation pressures? 

• If an injection depth waiver is to be granted, is the proposed well plugging plan designed to 

protect USDWs both above and below the injection zone? 

The submittal, evaluation, and approval of the Injection Well Plugging Plan may be an iterative 

process, involving multiple drafts of the plan until all required information is submitted in an 

appropriate format and level of detail. If the UIC Program Director has reason to believe, based 

on site-specific conditions, that additional data are needed to sufficiently address risk at the site, 

it is within his/her authority to request that additional information be collected or additional 

activities be included in the Injection Well Plugging Plan. The approved Injection Well Plugging 

Plan is enforceable, whether or not it is a condition of the permit, because the plan itself and the 

UIC Program Director’s approval are required by the Class VI Rule [40 CFR 146.93(a)]. 

Interaction and conversation between the owner or operator and UIC Program Director on the 

proposed plugging methods and materials are encouraged. Such discussions prior to developing 

and submitting the plan can increase the chance that the proposed plan is approved and can 

minimize the need for plan revisions. 

Appendix F of this guidance document presents a checklist of questions and considerations that 

UIC Program Directors may use when evaluating the proposed Injection Well Plugging Plan or 

other GS project plans. See the UIC Class VI Program Implementation Manual for additional 

information on how the UIC Program Director may evaluate the Injection Well Plugging Plan.

4.3 Amending the Injection Well Plugging Plan 

The Class VI Rule does not require formal periodic reviews and amendments to the Injection 

Well Plugging Plan throughout the injection phase (i.e., following any AoR reevaluations, as 

with other project plans) because changes to this plan would not be implemented until the end of 

injection activities. However, EPA suggests that owners or operators discuss with the UIC 

Program Director how any changes in facility operations or any other data that would warrant 

amendments to the other plans may affect the Injection Well Plugging Plan. EPA also 

recommends that the owner or operator review the Injection Well Plugging Plan if there are 

significant changes to the facility, such as the addition of another Class VI injection well, or if 

any adverse events require an emergency response. 

The Class VI Rule requires that the owner or operator submit a notice of intent to plug the 

injection well to the UIC Program Director at least sixty (60) days prior to plugging [40 CFR 

146.92(c)]. If any changes have been made to the original Injection Well Plugging Plan (e.g., 

based on operational and monitoring data or data collected during AoR reevaluations), the owner 

or operator must submit a revised plan at the same time as providing the notice of intent [40 CFR 

146.92(c)].
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Prior to plugging the injection well, owners or operators may choose to consider the operational 

and monitoring history of the facility and identify whether any information or events warrant 

amendment of the Injection Well Plugging Plan. Data that may be considered include: 

• Monitoring data related to chemistry of the carbon dioxide plume and formation fluids; 

• MIT results, including any mechanical integrity problems that may have occurred during the 

injection phase; 

• Operational data (e.g., injection rates and volumes); and/or 

• Any significant changes to the facility that may affect plugging of the injection well.

EPA encourages early interaction if the owner or operator or the UIC Program Director believe 

that changes to the Injection Well Plugging Plan are needed to ensure that the well is properly 

plugged in a manner that will be protective of USDWs. These discussions can also help the 

owner or operator understand the UIC Program Director’s expectations for the process. If the 

Injection Well Plugging Plan requires amendment, such open communication between the owner 

or operator and the UIC Program Director can improve the chances that the amended plan will be 

approved with as few revisions as possible. 

EPA recommends that the amended Injection Well Plugging Plan include the same type of 

information that was included in the original plan developed before injection commenced (see 

Section 4.1 of this guidance document for a description of the required elements). The amended 

plan must be approved by the UIC Program Director, and would then be incorporated into the 

permit. If changes to the plan are necessary, the UIC Program Director may need to modify the 

permit. A permit modification under 40 CFR 144.39 (e.g., to incorporate significant changes to 

planned injection well plugging activities because the initially planned activities were later 

determined to be inadequate) would require notification to the public and an opportunity for 

comment. See 40 CFR Part 124 for the details on the process. Minor changes to the plan, as 

defined under 40 CFR 144.41 (e.g., to provide clarification or correct typographical errors), do 

not require a permit modification or a public process under 40 CFR Part 124. See the Draft UIC 

Program Class VI Implementation Manual for additional information about the procedures for 

modification of Class VI permits and the related plan amendments. 

5.0 Post-Injection Site Care (PISC) and Site Closure Plan 

Following cessation of injection activities, Class VI injection well owners or operators must 

conduct comprehensive site monitoring until the owner or operator can demonstrate to the UIC 

Program Director that the GS project does not pose a risk of endangerment to USDWs. The PISC

requirements for GS projects incorporate a combination of both a fixed timeframe and a 

performance standard approach that recognizes that carbon dioxide plumes and associated 

pressure fronts may continue to move in the subsurface for long periods of time, while 

accounting for the variety of site-specific circumstances that may be brought to bear on 

determining the appropriate duration of PISC [40 CFR 146.93]. 

The Class VI injection well PISC and Site Closure Plan will ensure—prior to commencement of 

carbon dioxide injection—that the owner or operator and the UIC Program Director agree on the 

procedures that need to be implemented to confirm that site monitoring continues after injection
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Development Guidance 

operations cease. The plan will also help ensure that appropriate procedures are in place to 

protect USDWs from endangerment. Development of the PISC and Site Closure Plan will 

facilitate the identification of the appropriate types and amounts of data needed to determine that 

the injected fluid and the carbon dioxide plume and pressure front do not endanger USDWs, and 

it will support a determination of the conditions that warrant an end to PISC (i.e., the GS project 

no longer poses an endangerment to USDWs) [40 CFR 146.93(a)].

5.1 Developing the Post-Injection Site Care and Site Closure Plan 

The Class VI Rule, at 40 CFR 146.93(a), presents the required elements of a PISC and Site 

Closure Plan. Owners or operators must submit a PISC and Site Closure plan that outlines the 

proposed post-injection monitoring strategies and how non-endangerment of USDWs will be 

ensured throughout the PISC period. 

EPA suggests that, in developing the PISC and Site Closure Plan, owners or operators consider 

how non-endangerment will be demonstrated (i.e., what post-operational monitoring data will be 

needed to make this demonstration), and develop a plan that collects an appropriate amount and 

the appropriate types of data. EPA also recommends that owners or operators consider how the 

data collected during PISC will eventually inform a non-endangerment demonstration and ensure 

that enough data are generated (i.e., a sufficient history) to make a satisfactory demonstration. 

Guidance on how to perform the activities to be carried out under the approved PISC and Site 

Closure Plan (e.g., performing the necessary monitoring) will be presented in the Draft UIC 

Program Class VI Well Plugging, PISC, and Site Closure Guidance, available at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm. Exhibit 4 of this guidance 

document presents the highlights of the Draft UIC Program Class VI Well Plugging, PISC, and 

Site Closure Guidance. 

The PISC and Site Closure Plan must be submitted with the Class VI permit application for 

approval by the UIC Program Director [40 CFR 146.82(a)(17)], and it must include a description 

of how the owner or operator will meet the requirements of 40 CFR 146.93(a). The Sections 

below provide a description of the required elements, how they may be described in the plan to 

demonstrate to the UIC Program Director’s satisfaction that the plan is sufficient, and 

considerations for owners or operators as they develop the plan. Appendix D of this guidance 

document presents a sample template of a PISC and Site Closure Plan.

5.1.1 Pre-injection and predicted post-injection pressure differentials in the injection 

zone 

The PISC and Site Closure Plan must include a prediction of the magnitude of the pressure 

differential between pre-injection and post-injection [40 CFR 146.93(a)(2)(i)]. These predictions 

are integral to estimating the risk of endangerment to USDWs and, therefore, the amount of 

monitoring that will be necessary throughout the PISC timeframe. Pressure differential plots 

should be provided at various locations within the AoR as a function of time. 

Predictions of pressure differential will be provided by the computational modeling performed 

for the AoR delineation (see Section 2.1 of this guidance document). As with the AoR 
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delineation, estimates of pressure decline should be based on site-specific geologic data (e.g., 

injection zone permeability, compressibility, the volume of the formation, and the presence of 

lateral stratigraphic confining features) and the planned injection volumes and rates. 

5.1.2 Predicted position of the carbon dioxide plume and pressure front at site 

closure 

Also, the PISC and Site Closure Plan must include the predicted position of the carbon dioxide 

plume and associated pressure front at site closure, as demonstrated by the AoR reevaluation 

process [40 CFR 146.93(a)(2)(ii)]. Site closure refers to the point at the end of PISC, following a 

demonstration that fluid movement has slowed and pressures have declined to the point that there 

is no longer a risk of endangerment to USDWs from the carbon dioxide injection activities. 

These predictions are integral to determining the area(s) where there may be a risk of 

endangerment to USDWs during PISC and, therefore, the area(s) that must be subject to PISC 

monitoring. These predictions should be presented as information overlain on regional base 

maps.

The predictions of the extent of the carbon dioxide plume and pressure front will be provided by 

the computational modeling performed for the AoR delineation and reevaluations under 40 CFR 

146.84(b); see Section 2.1 of this guidance document. It is expected that the owner or operator 

would use these modeling results in order to comply with this plume position prediction 

requirement. As with the AoR delineation, these plume predictions should be based on the sitespecific geologic data (e.g., injection zone permeability, compressibility, the volume of the 

formation, and the presence of lateral stratigraphic confining features), and planned injection 

volumes and rates. 

5.1.3 Monitoring location, methods, and proposed frequency 

The PISC and Site Closure Plan must describe the owner’s or operator's planned monitoring 

regime to be conducted following the cessation of injection [40 CFR 146.93(a)(2)(iii)]. In 

general, it is recommended that post-injection monitoring be an extension of relevant 

operational-phase monitoring activities, including ground water monitoring and carbon dioxide 

plume and pressure front tracking. 

In the early post-injection phase, it may be appropriate to continue monitoring at the same 

locations, parameters, and frequency as specified in the operational-phase Testing and 

Monitoring Plan. Thus, the PISC and Site Closure Plan may resemble certain aspects of the 

Testing and Monitoring Plan (see Section 3 of this guidance document). Reduced monitoring 

frequencies and parameters may be appropriate as the owner or operator demonstrates, based on 

monitoring data, that movement of the carbon dioxide plume and pressure front is slowing and 

that there are no adverse changes in ground water geochemistry that could indicate that USDWs 

are being endangered. Conversely, if there is evidence of changes in ground water chemistry or 

plume movement, additional monitoring may be warranted.

As with injection-phase monitoring, appropriate monitoring technologies may vary depending on 

site-specific conditions; therefore, the techniques used to collect and interpret this data are not 

specified in the Class VI Rule. In developing a post-injection monitoring regime, EPA 
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recommends that the owner or operator consider what data will be needed as inputs for the nonendangerment demonstration. That demonstration will need to be based on a sufficient 

monitoring history to demonstrate that pressures have declined and that there is no risk of 

endangerment to USDWs from GS activities. 

5.1.4 Schedule for submitting post-injection site care monitoring results

The owner or operator must propose, in the PISC and Site Closure Plan, an appropriate schedule 

for reporting all testing and monitoring results collected during the post-injection monitoring 

phase [40 CFR 146.93(a)(2)(iv)]. The owner or operator and the UIC Program Director may 

wish to consider the submittal of these reports as an opportunity to discuss the rate of fluid 

movement, pressure changes, and any other significant processes within the subsurface, as well 

as whether modifying the testing frequency is appropriate. 

Many of the considerations applied in developing the operational-phase Testing and Monitoring 

Plan may also be used in planning for post-injection site monitoring. Discussions between the 

owner or operator and the UIC Program Director are encouraged—as the PISC and Site Closure 

Plan is developed, and as PISC monitoring proceeds. 

5.1.5 Demonstration of an alternative post-injection site care timeframe

At the UIC Program Director's discretion, the owner or operator may demonstrate during the 

permitting process that an alternative post-injection site care timeframe, other than the 50 year 

default, is appropriate and ensures non-endangerment of USDWs [40 CFR 146.93(a)(2)(v)]. 

To be acceptable to the UIC Program Director, the demonstration should be based on sitespecific information, including the results of site-specific computational modeling; the predicted 

timeframe for pressure decline; the predicted rate of carbon dioxide plume migration; sitespecific chemical processes that will result in carbon dioxide trapping; the predicted rate of 

carbon dioxide trapping; characterization of the confining zone(s); laboratory analyses or studies 

to verify the information on trapping; the presence of potential conduits for fluid movement and 

the quality of abandoned well plugs within the AoR; the distance between the injection zone and 

USDWs above and/or below the injection zone; and any additional site-specific factors 

determined by the UIC Program Director. 

The demonstration must meet the criteria at 40 CFR 146.93(c)(2) for ensuring the quality and 

accuracy of the data and models on which the demonstration is based. This demonstration would 

be submitted as part of the permit application, per 40 CFR 146.82(a)(18), in addition to the PISC 

and Site Closure Plan. The PISC and Site Closure Plan would reference this demonstration and 

include information about the appropriate alternative timeframe, if applicable.

The following factors may be considered and included in developing the PISC and Site Closure 

Plan: 

• The predicted size and shape of the AoR, which would affect the number and location of 

monitoring wells or the extent of geophysical surveys; 
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• Predicted pressure changes during and following injection, e.g., the rate at which pressures 

are predicted to decline, which would impact appropriate testing frequencies; 

• The site characteristics, depth and proximity of USDWs, and the depth and thickness of the 

confining zone(s), which may affect the amount of monitoring needed; 

• Baseline subsurface aqueous- and solid-phase geochemistry at the site and the composition 

of the carbon dioxide, which would impact ground water monitoring needs; and

• Planned information needs for non-endangerment demonstrations for determining the 

end of the PISC period. 

5.1.6 Information that will Support the Non-Endangerment Demonstration 

EPA recommends that owners or operators include in the PISC and Site Closure Plan a 

discussion of what data will inform the non-endangerment demonstration at the end of postinjection site care and how the owner or operator envisions the non-endangerment demonstration 

will be developed. This section of the Plan may take the form of a rough outline of the 

information that will comprise the non-endangerment demonstration, e.g., trends in subsurface 

pressures or certain ground water monitoring data and may include predicted values based on 

project-specific information and modeling. Such a discussion would allow the owner or operator 

and the UIC Program Director to agree, up front, on the types of project data that will be 

collected and used to indicate that the carbon dioxide plume is stabilizing and there is no further 

risk of endangerment to USDWs. This approach would ensure that the data the owner or operator 

plans to collect (e.g., the types of data described in Section 5.1.5) will be of the appropriate type 

and frequency to provide sufficient data to inform a demonstration that site closure is 

appropriate. 

5.1.7 Site Closure Plan 

EPA recommends that owners or operators also describe in their PISC and Site Closure Plan how 

they plan to close the site following the conclusion of the PISC period. Site closure activities 

may include: plugging all monitoring wells, removing all surface equipment, and restoring the 

site to its prior condition (e.g., planting vegetation). 

The primary activity associated with site closure is plugging all monitoring wells in a manner 

that will not allow movement of injection or formation fluids that endangers a USDW [40 CFR 

146.93(e)]. An improperly abandoned monitoring well poses as great a threat to USDWs as an 

improperly abandoned injection well. EPA anticipates that plugging monitoring wells will 

involve similar activities as those required for plugging the injection well(s), i.e., flushing the 

well with a buffer fluid, testing the external mechanical integrity of the well, and emplacing 

cement in the well in a manner that will prevent fluid movement that may endanger USDWs. 

Owners or operators may consider the same types of information in planning the closure of 

monitoring wells as they did for plugging the injection well: well depth and construction; the 

location, type, and depth of subsurface formations penetrated; and how the composition of the 

carbon dioxide may impact plugging materials. See Section 4.1 of this guidance document and 

the Draft UIC Program Class VI Well Plugging, PISC, and Site Closure Guidance for additional 

information on well plugging. 
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5.2 UIC Program Director’s Evaluation of the Post-Injection Site Care and Site Closure 

Plan

The UIC Program Director will evaluate the owner’s or operator’s proposed PISC and Site 

Closure Plan, along with the geologic and proposed operating data submitted with the Class VI

permit application. Therefore, the owner or operator must demonstrate in the proposed PISC and 

Site Closure Plan, to the satisfaction of the UIC Program Director, that the planned PISC will be 

adequate to detect any endangerment to USDWs from injection operations. 

The UIC Program Director should evaluate the proposed PISC and Site Closure Plan to verify 

that all required elements as described in 40 CFR 146.93(a) are present and that they account for 

all site-specific conditions to ensure that USDWs are protected from endangerment. For 

example:

• Are predictions of pressure decline and fluid movement consistent with AoR modeling and 

do they accurately reflect geologic and operating data?

• Is the proposed carbon dioxide plume and pressure front tracking appropriate to the predicted 

changes in subsurface conditions during post-injection? 

• Is the proposed post-injection monitoring (e.g., ground water quality monitoring) adequate to 

provide early warning of USDW endangerment? 

• If an alternative PISC timeframe is proposed, does substantial data exist to demonstrate that 

an alternative timeframe would be protective of USDWs and does it meet the criteria at 40 

CFR 146.93(c)(2)? 

EPA envisions that the submittal, evaluation, and approval of the PISC and Site Closure Plan 

will be an iterative process. This may involve multiple rounds of drafts until all required 

information is submitted in an appropriate format and level of detail. In particular, if the owner 

or operator plans to demonstrate that an alternative PISC timeframe is appropriate, it is 

recommended that they discuss this with the UIC Program Director, including the types of data 

that are available to support the demonstration. The demonstration must be submitted as part of 

the permit application [40 CFR 146.82(a)(18)], and the timeframe must be incorporated into the 

PISC and Site Closure Plan. If the UIC Program Director has reason to believe (e.g., based on 

site-specific conditions) that additional data are needed to sufficiently address the risks at the site 

during the post-injection phase, it is within his or her authority to request that additional 

monitoring be performed. The approved PISC and Site Closure Plan is enforceable, whether or 

not it is a condition of the permit, because the plan itself and the UIC Program Director’s 

approval are required by the Class VI Rule [40 CFR 146.93(a)]. 

Interaction and conversation about the proposed monitoring and other site care activities are 

encouraged. In particular, it is important that the owner or operator discuss with the UIC 

Program Director how he or she plans to demonstrate a reduction in risk to USDWs posed by the 

GS project during the PISC period. Such demonstrations can support reductions in the frequency 

of PISC monitoring or reduce the PISC monitoring timeframe (i.e., by allowing nonendangerment to be demonstrated in less than 50 years after the cessation of injection). EPA 

recommends that the owner or operator discuss the anticipated data that will be used and how it 

will be presented and analyzed. For more information on performing the non-endangerment 
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Development Guidance 

The PISC Timeframe

The Class VI Rule sets a default timeframe of 

fifty (50) years of PISC, and it affords the UIC 

Program Director the discretion to shorten the 

PISC timeframe if the owner or operator can 

demonstrate that there is substantial evidence that 

the GS project no longer poses a risk of 

endangerment to USDWs [§146.93(b)]. 

Likewise, the UIC Program Director may 

lengthen the PISC timeframe if, after fifty (50) 

years, USDWs still may become endangered. 

demonstration, see the Draft UIC Program Class VI Well Plugging, PISC, and Site Closure 

Guidance. 

The owner or operator must notify the UIC Program Director, in writing, of their intent to close 

the site at least 120 days prior to site closure and cessation of PISC activities [40 CFR 

146.93(d)]. At this time, the owner or operator should submit to the UIC Program Director any 

changes to the PISC and Site Closure Plan.

Appendix F of this guidance document presents a checklist of questions and considerations that 

UIC Program Directors may use when evaluating the proposed PISC and Site Closure Plan and 

other GS project plans. See the Draft UIC Program Class VI Implementation Manual for 

additional information on how the UIC Program Director might evaluate the PISC and Site 

Closure Plan.

5.3 Amending the Post-Injection Site Care and Site Closure Plan 

Upon cessation of injection, the Class VI Rule requires that owners or operators either submit an 

amended PISC and Site Closure Plan or demonstrate to the UIC Program Director, through 

monitoring data and modeling results, that no amendment to the plan is needed [40 CFR 

146.93(a)(3)]. 

The Class VI Rule does not require formal periodic reviews and amendments to the PISC and 

Site Closure Plan during the injection phase (i.e., following AoR reevaluations, as with other 

project plans), because it is not expected that changes to this plan would be implemented until 

the end of injection activities. However, if any changes in facility operations or monitoring or 

operational data warrant changes to other GS project plans, EPA recommends that the owner or 

operator consider discussing the PISC and Site Closure Plan and potential impacts to planned 

PISC and site closure activities with the UIC Program Director. If any adverse events or a 

significant deviation from predicted performance occur, the UIC Program Director may require a 

review of the PISC and Site Closure Plan. EPA recommends that the owner or operator also 

undertake a review of the plan if there are significant changes to the facility, such as the addition 

of an injection well, or if any adverse events requiring the implementation of an emergency 

response occur. 

During the post-injection monitoring phase, EPA 

expects the owner or operator to continue to 

review the PISC and Site Closure Plan. As the 

owner or operator performs post-injection 

monitoring, they may take into account similar 

considerations that guide amendments to the 

other project plans. For example, if carbon 

dioxide plume and pressure front tracking data 

indicate a divergence from modeled predictions 

or ground water monitoring data indicates 

leaching/ mobilization of contaminants (or reductions in previously observed reactions), an 

amendment to the PISC and Site Closure Plan may be appropriate. 
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The purpose of reviewing the PISC and Site Closure Plan is to consider: 

• Whether post-injection site care is adequate to ensure that USDWs are protected from 

endangerment from carbon dioxide injection activities (or provide early warning of potential 

endangerment);

• Whether changes to monitoring are needed, e.g., if the types of monitoring can be reduced as 

data indicate post-injection stabilization of the carbon dioxide plume and pressure front; and 

• Whether appropriate amounts and types of data are being collected to support an eventual 

non-endangerment demonstration, and whether making this demonstration before the 

required fifty (50) year PISC timeframe is appropriate. The UIC Program Director may 

determine whether a shorter or longer PISC timeframe is necessary.

The owner or operator may choose to amend the PISC and Site Closure Plan if monitoring or 

operational data indicate that changes to the PISC timeframe are warranted. The owner or 

operator may, at any time during the life of the project, submit information to support a revised 

PISC timeframe other than the initial or previously approved timeframe in the PISC and Site 

Closure Plan. This demonstration must be based on monitoring and operational data collected 

during site operations and modeling of the extent of the carbon dioxide plume and pressure front. 

EPA recommends that, if the owner or operator opts to revise their PISC timeframe as part of a 

PISC and Site Closure Plan update, they submit information that meets all of the criteria at 40 

CFR 146.93(c) to demonstrate that the timeframe is appropriate and protective of USDWs. 

This option is available to either amend an alternative PISC timeframe that was included in the 

original PISC and Site Closure Plan submitted with the Class VI permit application or to justify 

that a revised timeframe is appropriate if the Class VI permit included the default PISC 

timeframe. If the UIC Program Director approves the revised PISC timeframe, it would be 

incorporated into the PISC and Site Closure Plan and the Class VI operating permit. Such a 

change would require the UIC Program Director to modify the Class VI permit. A permit 

modification under 40 CFR 144.39 would require notification to the public and an opportunity 

for comment. 

As discussed earlier, the Class VI Rule does not set a required frequency or a schedule for the 

review of the PISC and Site Closure Plan during the PISC phase. However, EPA encourages the 

owner or operator and UIC Program Director to discuss the monitoring data collected during the 

PISC phase in order to identify whether amendments to the plan are needed. These discussions 

can coincide with the reporting schedule identified in the owner or operators original PISC and 

Site Closure Plan [40 CFR 146.93(a)(2)(iv)].

EPA encourages the owner or operator and the UIC Program Director to coordinate and discuss 

monitoring data and other information about the facility throughout PISC, particularly if the 

owner or operator seeks to amend the PISC timeframe. This dialogue is an important part of the 

process to ensure that the GS project is (and continues to be) managed appropriately to protect 

USDWs and that compliance with the Class VI operating permit is achieved. These discussions 

can also help the owner or operator understand the UIC Program Director’s expectations, 

including whether an amended PISC and Site Closure Plan is needed and, if so, improve the 
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Development Guidance 

chance that the amended plan will be approved by the UIC Program Director with minimal

revisions. 

If any changes to the original PISC and Site Closure Plan are needed at the time of cessation of 

injection, the owner or operator must submit an amended PISC and Site Closure Plan for the UIC 

Program Director’s approval within thirty (30) days of making the changes [40 CFR 

146.93(a)(4)]. If the UIC Program Director determines that a plan amendment is needed during 

the post-injection phase, the owner or operator and UIC Program Director are encouraged to

agree on a schedule for submittal of the amended PISC and Site Closure Plan. 

If an amendment is needed, the amended PISC and Site Closure Plan may include the same type 

of information that was included in the original plan developed and submitted with the Class VI

permit application (see Section 5.1 of this guidance document for a description of the required 

plan elements).

Any amendments to the PISC and Site Closure Plan (either at the time of cessation of injection 

or during the PISC phase) must be incorporated into the Class VI operating permit once the 

amendments are approved by the UIC Program Director. If changes to the plan are needed, the 

UIC Program Director may need to modify the permit. A permit modification under 40 CFR 

144.39 (e.g., to incorporate a plan with changes to the initially planned types of monitoring or an 

expansion of the area covered by post-injection monitoring, or to establish or revise the 

alternative PISC timeframe) would require notification to the public and an opportunity for 

comment. Minor changes to the plan, as defined under 40 CFR 144.41 (e.g., to provide 

clarification or correct typographical errors), do not require a permit modification or a public 

process under 40 CFR Part 124. See the Draft UIC Program Class VI Implementation Manual

for additional information about the procedures for modification of Class VI permits and the 

related plan amendments. 

6.0 Emergency and Remedial Response Plan 

While the goals of proper siting, construction, and operation of a GS project are to prevent the 

occurrence of an emergency or adverse event, advance planning is vital for mitigating the effects 

of such an event, if it should ever occur. The Emergency and Remedial Response Plan helps 

ensure that in the unlikely event of an emergency or USDW endangerment, an approved process 

is implemented in order to facilitate and expedite the necessary and appropriate response efforts. 

Evidence of advance planning can also allay public concerns about the project’s safety. The

Emergency and Remedial Response Plan will apply over the life of the GS project, including 

throughout the PISC period [40 CFR 146.94(a)]. 

The purpose of requiring an Emergency and Remedial Response Plan is to ensure that owners or 

operators can comprehensively plan for what actions would be necessary in the unlikely event of 

an emergency. The plan will also ensure that operators know which entities and individuals are 

to be notified, and what actions need to be taken, to expeditiously mitigate any emergency 

situations and protect USDWs from endangerment. 
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Development Guidance 

6.1 Developing the Emergency and Remedial Response Plan 

The Class VI Rule, at 40 CFR 146.94(a), requires that the Emergency and Remedial Response 

Plan describe the measures that would be taken in the event of adverse conditions at a GS 

project, such as a loss of the well's mechanical integrity, or if movement of injection or 

formation fluids caused an endangerment to a USDW. The Emergency and Remedial Response 

Plan must be submitted with the Class VI permit application for approval by the UIC Program 

Director [40 CFR 146.82(a)(19)]. It must include a description of how the owner or operator will 

meet the requirements of 40 CFR 146.94, and it must demonstrate, to the satisfaction of the UIC 

Program Director, that in the event of an emergency, the appropriate response actions would be 

performed in a timely manner to prevent or mitigate any damage to USDWs. 

The Class VI Rule does not identify the specific elements of the Emergency and Remedial 

Response Plan. EPA envisions that each plan will be site-specific and risk-based, and depend on 

a variety of factors, including the nature of any movement of carbon dioxide or other fluids, the 

presence of USDWs, and what, if any, impacts could result from carbon dioxide movement into 

unintended zones, carbon dioxide leaks, or ground water or surface water contamination. 

This Section describes an EPA-recommended process that an owner or operator may undertake 

in developing an Emergency and Remedial Response Plan. This approach includes 

considerations of site-specific factors, potential risk scenarios to USDWs or resources, and 

appropriate response actions and personnel. Appendix E of this guidance document presents a 

sample template for an Emergency and Remedial Response Plan. For more information on 

conducting outreach and communicating with the public on any potential Class VI injection well 

project, see the Public Participation Considerations for Geologic Sequestration Projects Fact 

Sheet, available on EPA’s website at 

http://water.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm. The steps recommended for 

developing an Emergency and Remedial Response Plan include the following: 

1. Identify and list resources/infrastructure. EPA recommends that the plan identify all 

potentially impacted environmental resources (e.g., ground water or surface water) or 

infrastructure (e.g., the well or nearby structures) near the well; such information will be of 

interest to the public. This list may be based on site-specific data collected in the site 

characterization and AoR processes. 

Potentially impacted resources or infrastructure near Class VI injection wells may include: 

the injection well, any public water systems, private drinking water wells, other deep wells 

within the AoR, aquifers and USDWs, surface water bodies, the soil column, buildings or 

other structures, biosphere/ecosystems, the atmosphere, and the geosphere. 

2. Identify potential risk scenarios. EPA recommends that the plan consider, for each 

identified resource or infrastructure element potentially at risk, any potential adverse events 

that may occur (e.g., a well blowout, unanticipated/emergency corrective action on deficient 

wells in the AoR, equipment failure, fluid movement, metals leaching, contamination of the 

water supply, earthquakes/land deformation, or carbon dioxide seeps into buildings that 

endanger occupants). The purpose of this analysis is to consider the “worst case” scenarios 

and to ensure that response plans are in place for all eventualities. If the responses would be 
UIC Program Class VI Well Project Plan 53 August 2012

Development Guidance 

similar (e.g., if any type of damage to the well would be addressed by engaging the services 

of an environmental contractor), it may be appropriate to describe categories of risks.

The Emergency and Remedial Response Plan may also consider whether the likelihood of 

the event is high, medium, or low, and tier the actions in the plan accordingly. For example, 

if baseline geochemical analyses indicate that there are no constituents in the rock matrix that 

could be potentially mobilized as a result of carbon dioxide exposure, ground water 

contamination from injection activities may be considered a low-risk scenario. However, it is 

still important that the scenario be considered and included in the plan.

3. Describe response actions to address the identified risk scenarios, e.g., remedial cementing 

of the well or treatment of ground water or drinking water supplies. Some situations may 

require an immediate response (e.g., shutting down the well), while other “non-immediate” 

actions would occur following consultation with the UIC Program Director. The proposed 

response actions should be tied to planned testing and monitoring so that the owner or 

operator can quickly respond to any endangerment detected at the site. 

High-impact risk scenarios may warrant special consideration in the Emergency and 

Remedial Response Plan. For example, if all residents in the vicinity of the well rely on one 

USDW for their drinking water supply, the plan might highlight how the owner or operator 

would respond expeditiously to any evidence of the contamination of that supply (including 

notifying the public of such an event).

All response actions must be initiated by immediately ceasing injection, taking all steps 

reasonably necessary to identify and characterize any release, notifying the UIC Program 

Director within twenty-four (24) hours, and implementing the approved Emergency and 

Remedial Response Plan [40 CFR 146.94(b)]. 

4. Identify the personnel and equipment needed to implement the response actions. These 

personnel may include first responders (e.g., fire departments or haz-mat units), GS project 

facility staff, or environmental contractors. EPA recommends that the plan be as specific as 

possible (e.g., by providing the names and titles of people who will respond) to avoid 

confusion in an emergency situation. Where facility staff are identified as responding 

personnel, the plan might describe their relevant training and exercises (e.g., emergency 

drills) and verify that qualified staff are always onsite during operations. For example, the 

plan may describe which staff receive training, the training materials used, and what actions 

staff will be able to perform after receiving this training. EPA also recommends that the plan 

identify where the necessary equipment will be procured.

Because response personnel may change from time to time, EPA encourages owners or 

operators to ensure that this list is reviewed and updated periodically. While such personnel 

changes would not necessarily warrant an amendment to the Emergency and Remedial 

Response Plan, the owner or operator may consider including a schedule for verifying and 

updating the list (i.e., every few months) in the plan.
UIC Program Class VI Well Project Plan 54 August 2012

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EPA recommends that the Emergency and Remedial Response Plan also include the following 

information: 

• Facility emergency 24-hour contacts, including phone/pager numbers and e-mail 

addresses;

• A list of people to notify in case of an adverse event (e.g., local water systems, carbon 

dioxide generators and pipeline operators, nearby land owners, the permitting authority, 

other states or countries in the AoR, or Regional Response Teams); 

• The location of the well, such as the specific town or county (this often drives who are 

first responders, applicable local ordinances, etc.); 

• A map of the area, including the location of the well and nearby population centers or 

sensitive environments. This map may be an adaptation of or enhancement to the map of 

the AoR required at 40 CFR 146.82(a)(2); 

• Schematics and diagrams of the facility and well, including the location of monitoring 

equipment and emergency shutoffs; and 

• A communications plan and emergency notification procedures that describe 

potential audiences (e.g., the public, community leaders), communication methods (e.g., 

newspapers or public service announcements), and messages. 

The details of an Emergency and Remedial Response Plan may be influenced by a variety of 

site-specific factors. EPA recommends that the following be considered in planning for 

emergency and remedial response:

• The size of the site and the AoR, including the volume of carbon dioxide injected and 

proposed operating conditions and properties of the carbon dioxide. For larger AoRs, 

more resources and infrastructure are potentially impacted; 

• The number of wells in the AoR and their age (for converted wells), which may affect 

the likelihood of a well failure or fluid movement; 

• The composition of the carbon dioxide and subsurface geochemistry and 

mineralogy, which would impact the potential for contamination of ground water or 

private and public water supplies; 

• Proximity and depth to potentially affected USDWs or other drinking water sources 

and public water supplies; 

• Resources located in the AoR, e.g., the presence of communities and sensitive 

populations, drinking water systems, residences, land uses, population centers, or 

buildings; 

• Whether the project will operate under an injection depth waiver. See the Class VI

Rule and the Draft UIC Program Class VI Injection Depth Waivers Guidance for more 

information about Class VI injection wells operating under approved waivers; and

• Procedures for immediate well shut-down and creating alternate options for the carbon 

dioxide stream.
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6.2 UIC Program Director’s Evaluation of the Emergency and Remedial Response Plan 

The UIC Program Director will evaluate the owner’s or operator’s proposed Emergency and 

Remedial Response Plan, along with the geologic and proposed operating data submitted with 

the Class VI permit application in determining whether to approve the plan. Therefore, the owner 

or operator must demonstrate in the proposed Emergency and Remedial Response Plan, to the 

satisfaction of the UIC Program Director, that any needed response will be adequate for 

mitigating any adverse events that may arise during injection and through the PISC period. 

The UIC Program Director should evaluate the proposed Emergency and Remedial Response 

Plan to verify that it meets the requirements of 40 CFR 146.94(a) and that the plan accounts for 

all site-specific conditions. For example:

• Are all potentially affected activities within the AoR, including the presence of population 

centers and all land uses, addressed in the plan? 

• Is special consideration given to events with the highest potential of occurring or to events 

that may have the highest impacts? 

• Are all reasonably anticipated potential adverse events at the facility addressed in the plan 

and are appropriate procedures, equipment, and trained personnel identified? 

• Are the planned response activities appropriate to the risk scenarios identified and their 

potential impacts on resources or infrastructure?

• Does the plan include proper procedures, including ties to the Testing and Monitoring Plan, 

for quickly detecting and responding to situations that may endanger USDWs? 

The submittal, evaluation, and approval of the Emergency and Remedial Response Plan are 

meant to be part of an iterative process. This may involve multiple rounds of drafts until all of 

the required information is submitted in an appropriate format and level of detail. If the UIC 

Program Director has reason to believe (e.g., based on site-specific conditions) that additional 

data are needed to sufficiently address risk at the site, it is within his/her authority to request that 

additional information be provided. The approved Emergency and Remedial Response Plan is 

enforceable, whether or not it is a condition of the permit, because the plan itself and the UIC 

Program Director’s approval are required by the Class VI Rule [40 CFR 146.93(a)]. 

Interaction and conversation between the owner or operator and the UIC Program Director are 

encouraged. Such discussions prior to developing and submitting the plan can increase the 

chance that the proposed plan will be approved and avoid the need to revise the plan. 

Appendix F of this guidance document presents a checklist of questions and considerations that 

UIC Program Directors may use when evaluating the proposed Emergency and Remedial 

Response Plan and other GS project plans. See the Draft UIC Program Class VI Implementation 

Manual for additional information on the UIC Program Director’s evaluation of the Emergency 

and Remedial Response Plan.
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6.3 Amending the Emergency and Remedial Response Plan 

The Class VI Rule requires that the Emergency and Remedial Response Plan be reviewed and, if 

necessary, amended following each reevaluation of the AoR [40 CFR 146.94(d)]. The purpose of 

this review is to ensure that management of the project and all of the project plans are based on 

the most up-to-date information available to allow a prompt response to potential USDW 

endangerment. This review of the Emergency and Remedial Response Plan follows the required 

AoR reevaluation, which must occur at least once every five (5) years (see the Draft UIC 

Program Class VI Well AoR Evaluation and Corrective Action Guidance for additional 

information on performing AoR reevaluations). The amended Emergency and Remedial 

Response Plan (or a demonstration that no amendment is needed) is due no later than one (1)

year after the reevaluation [40 CFR 146.94(d)(1)]. 

EPA recommends that reviews of the Emergency and Remedial Response Plan continue through 

the post-injection phase. As the owner or operator submits monitoring data collected during 

PISC (See Section 5.1.4 of this guidance document), they are encouraged to discuss the results 

with the UIC Program Director to identify whether any amendments to the Emergency and 

Remedial Response Plan are needed.

EPA recommends that owners or operators use the results of the AoR reevaluation, along with 

the monitoring (e.g., carbon dioxide plume and pressure front tracking and ground water 

monitoring) and operational data (e.g., injection rates and volumes) collected since the last AoR 

reevaluation, to assess the need for amending the Emergency and Remedial Response Plan. The 

owner or operator is also encouraged to review the plan if there are significant changes to GS 

facility operations, such as the addition of an injection well or if any adverse events occurred that 

required the implementation of the Emergency and Remedial Response Plan. 

The owner or operator and the UIC Program Director are encouraged to coordinate and discuss 

the most recent AoR evaluation, along with monitoring and operational data, and other 

information about the Class VI injection well during this review. This dialogue is an important 

part of the process to ensure that the GS project is (and continues to be) managed appropriately 

to protect USDWs, and that compliance with the Class VI operating permit is achieved. These 

discussions can also help the owner or operator understand the UIC Program Director’s 

expectations, including whether an amended plan is needed so that the UIC Program Director 

receives all the required information up front in order to facilitate the review process. 

The Sections below describe a recommended process by which the owner or operator may 

review and amend the Emergency and Remedial Response Plan.

Step 1: Review the results of the AoR reevaluation or relevant monitoring and operational 

data. The purpose of this review is to identify whether an amendment to the Emergency and 

Remedial Response Plan is needed. Topics to be considered in the review include: 

• If the most recent AoR reevaluation required a revision to the AoR computational model or 

any changes to the prediction of plume and pressure front movement; 
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• Whether any of the considered emergency scenarios are more likely to occur than originally 

considered (e.g., if ground water chemistry is changing); 

• Whether MIT results indicate increased concerns for well failures; 

• If recent (or planned) land use changes brought new resources or infrastructure near or into 

the AoR; or 

• If there has been a need to implement emergency procedures at the site, lessons learned 

might be incorporated into an amended Emergency and Remedial Response Plan. 

Step 2: Discuss the results with the UIC Program Director. The owner or operator and the UIC 

Program Director are encouraged to discuss whether an amendment to the Emergency and 

Remedial Response Plan is needed. If the AoR reevaluation and monitoring/operating data were 

to show that the plume is moving as predicted, an amendment may not be needed. The final

decision regarding the need for an amended plan will be made by the UIC Program Director. 

If a review of the AoR reevaluation or other project data indicate that an amendment to the 

Emergency and Remedial Response Plan is necessary, then EPA recommends that work on 

revising the plan begin so that the one (1) year deadline for amending this plan (along with any 

necessary amendments to other related project plans) can be met. In lieu of a conversation with 

the UIC Program Director, the owner or operator might use the site-specific monitoring and 

operational data to prepare and present a recommendation for action on an amended Emergency 

and Remedial Response Plan. If, based on a review of all available data and information, no 

amendment is needed, the existing approved Emergency and Remedial Response Plan remains in 

force. 

Step 3: Amend the Emergency and Remedial Response Plan if needed. EPA recommends that 

the amended Emergency and Remedial Response Plan include the same categories of 

information that were in the original plan developed before injection commenced (see Section 

6.1 of this guidance document). EPA recommends that the amended plan include the following 

information (as warranted):

• The addition of newly identified resources or infrastructure that should be addressed in the 

Plan, e.g., additions to the facility, new construction within the AoR, or newly identified 

resources based on changes to the modeled AoR; 

• Updates to the list of responding personnel or their training; 

• Modifications to communications and notification procedures to address population or land 

use changes; 

• Any newly developed procedure that was not in the approved Emergency and Remedial 

Response Plan; and

• Lessons learned, if any events necessitated the prior implementation of the Emergency and 

Remedial Response Plan.

Step 4: Submit the amended plan. The Class VI Rule requires that the owner or operator submit 

the amended Emergency and Remedial Response Plan to the UIC Program Director for approval 

within one (1) year of the AoR reevaluation or within one (1) year of other event that triggers an 

Emergency and Remedial Response Plan review [40 CFR 146.94(d)(1) and 146.94(d)(2)]. The 

owner or operator and UIC Program Director are encouraged to establish a schedule for 
UIC Program Class VI Well Project Plan 58 August 2012

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submitting amendments to the Emergency and Remedial Response Plan during the post-injection 

monitoring phase. 

The amended plan must be approved by the UIC Program Director and would then be 

incorporated into the Class VI permit. If significant changes to the plan are needed, the UIC 

Program Director may need to modify the permit. A permit modification under 40 CFR 144.39 

(e.g., to incorporate a plan that involves additional resources or infrastructure) would require 

notification to the public and an opportunity for comment. See 40 CFR for more details on the 

process. Minor changes to the plan, as defined under 40 CFR 144.41 (e.g., to provide 

clarification, change contact information, or correct typographical errors), do not require a permit 

modification or a public process under 40 CFR Part 124. See the Draft UIC Program Class VI

Implementation Manual for additional information about the procedures for modification of 

Class VI permits and the related plan amendments. 
Appendix A

Sample Template of an Area of 

Review and Corrective Action 

Plan
UIC Program Class VI Well Project Plan 

A-2 August 2012

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UIC Program Class VI Well Project Plan A-3 August 2012

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Appendix A: Sample Template of an Area of Review and Corrective Action Plan

Facility Information 

Facility name:

Facility contacts (names, titles, phone numbers, email addresses):

Location (town/county/etc.): 

Computational Modeling

Model Name:

Model Authors/Institution:

Description of model:

Model Inputs and Assumptions: 

EPA recommends that this section describe how each of the following types of 

information will be used to inform the computational modeling. EPA recommends that 

owners or operators reference geologic reports and data submitted with the Class VI

permit application as appropriate. The owner or operator should also provide the values 

of all model parameters, any constitutive relationships, proposed modeling timeframe, 

and proposed initial and boundary conditions. 

• Subsurface formations (including the type and number of formations between the 

uppermost USDW and the injection zone, heterogeneity of the geologic 

stratigraphy, and permeability);

• Geologic structure (including faults or fractures); 

• Hydrogeologic information (including initial fluid pressures, horizontal and 

vertical gradients, ground water flow direction and velocity); 

• Geochemistry and compatibility of injectate fluids (including soil and rock 

chemistry or potential mineralization reactions); 

• Proposed operating data (e.g., injection rates and pressures and injection 

depths);

• Other injection operations, mines or other subsurface activities, and abandoned 

wells (including the number, depth, and description of injection points in each 

geologic formation); and 

• If an injection depth waiver is being requested, explain here how the model 

accounts for all USDWs that can be affected. 
UIC Program Class VI Well Project Plan A-4 August 2012

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Corrective Action Plan and Schedule

Pre-Injection Corrective Action Schedule

Well Name/ 

Location

Planned Date of 

Corrective 

Action

Planned Corrective 

Action Method Notes

Include each 

deficient well in 

the AoR.

References to 

map(s) may be 

appropriate.

The dates should 

be consistent with 

AoR model 

results.

Including the type, volume,

and depth of plugs to be 

used or other risk 

management strategies.

Reference well schematics 

as appropriate.

Considerations that drive the 

corrective action plans, e.g., age 

and maintenance of the well; 

cement condition; well 

depth/subsurface formations 

penetrated; or formation 

fluid/carbon dioxide stream 

geochemistry. Confirmation of 

site access.

Plan for Site Access

Describe here how access to all wells needing corrective action will be guaranteed. 

Phased Corrective Action Schedule

Well Name/ 

Location

Planned Date of 

Corrective Action

Planned Corrective 

Action Method Notes

Justification of Phased Corrective Action

Describe why corrective action on certain wells can be deferred based on preliminary 

information about the AoR.

Attachments

Preliminary maps of the AoR with deficient wells identified 

Plugging schematics
UIC Program Class VI Well Project Plan A-5 August 2012

Development Guidance 

Area of Review Reevaluation Plan and Schedule

Reevaluation Strategy 

Describe what will be involved in an AoR reevaluation, including the types and amount 

of input data that will be used to update the model, e.g., operating data, carbon dioxide 

plume and pressure front tracking results, geochemical monitoring data, or information 

on other operators (i.e., of injection or production wells) in the AoR. 

Proposed Reevaluation Cycle 

Identify the frequency at which reevaluations are planned (in no case can this be less 

often than every five [5] years). Present a justification, based on: 

• Anticipated plume movement relative to land uses or other features that may 

be potentially affected or intersected. 

• Neighboring projects expected to come online or that will also be injecting 

carbon dioxide. 

• Development, land use changes, and population growth. 

• Phased corrective action, if planned. 

• Modeling issues, i.e., whether any uncertainty in the model or assumptions 

may warrant frequent reevaluations. 

• Planned injection volumes and rates. 

• Public opinion or concerns. 

 

Triggers for AoR Reevaluations Prior to the Next Scheduled Reevaluation

Trigger Time Frame for Reevaluation

Change in rate, direction, or extent of carbon dioxide plume

movement

e.g., within one (1) month of 

detection

Operating changes, e.g., carbon dioxide injection rates/volumes

New owners or operators in AoR/ new injection well(s) online

New site characterization data

Seismic Event or Other Emergency

Violation of Permit Conditions

Other...
UIC Program Class VI Well Project Plan A-6 August 2012

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Appendix B

Sample Template of a Testing 

and Monitoring Plan
UIC Program Class VI Well Project Plan 

B-2 August 2012

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UIC Program Class VI Well Project Plan B-3 August 2012

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Appendix B: Sample Template of a Testing and Monitoring Plan

Facility Information 

Facility name:

Facility contacts (names, titles, phone numbers, email addresses):

Location (town/county/etc.):

Carbon Dioxide Stream Analysis

Parameter/Analyte Frequency

pH

Temperature 

Etc...

Sampling methods:

Analytical techniques:

Laboratory to be used/chain of custody procedures:

Quality assurance and surveillance measures:

Continuous Recording of Injection Pressure, Rate, and Volume; Annulus Pressure

• Describe the recording devices to be used, quality assurance and surveillance measures,

the frequency at which the information will be recorded, and how the data will be 

recorded and reported.

Corrosion Monitoring

• Describe the corrosion monitoring method to be used and associated quality assurance 

and surveillance measures, and a schedule for performing the quarterly tests (e.g., 

anticipated testing dates) and how the data will be reported. 
UIC Program Class VI Well Project Plan B-4 August 2012

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Ground Water Quality Monitoring

Monitoring well name/location/map reference:

Well depth/formation(s) sampled:

Parameter/Analyte Frequency

Aqueous and pure phase carbon dioxide

Total dissolved solids 

pH

Specific conductivity (SC)

Temperature 

Other parameters (e.g., major anions and cations; trace metals; 

tracers; hydrocarbons; and volatile organic compounds)

Sampling methods:

Analytical techniques:

Laboratory to be used/ chain of custody procedures:

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:

External Mechanical Integrity Testing

• Describe specific MIT(s) to be employed, associated quality assurance and surveillance 

measures, anticipated testing dates, and plans to record and report the results.

Pressure Fall-Off Testing

• Describe the pressure fall-off tests to be employed, associated quality assurance and 

surveillance measures, anticipated testing dates, and plans to record and report the test 

results.

Carbon Dioxide Plume and Pressure Front Tracking

Direct Pressure Monitoring

Well Location/Map Reference Depth(s)/Formation(s) Frequency

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:
UIC Program Class VI Well Project Plan B-5 August 2012

Development Guidance 

Indirect Carbon Dioxide Plume and Pressure Front Tracking 

• Describe indirect methods to be used (e.g., types of indirect surveys to be performed, the 

planned areal extent/resolution of geophysical surveys, and planned frequency/schedule) 

and their associated quality assurance and surveillance measures, and plans to record 

and report the results.

• If indirect methods cannot be used, describe why.

Direct Geochemical Plume Monitoring

• If it is determined that direct geochemical monitoring of the plume is necessary, describe 

the locations where samples will be taken and parameters to be monitored.

Monitoring Location/Map Reference Frequency

Sampling methods:

Analytical techniques:

Laboratory to be used/ chain of custody procedures:

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:

Surface Air and/or Soil Gas Monitoring (if required by the UIC Program Director)

Monitoring Location/Map Reference Frequency

Sampling methods:

Analytical techniques:

Laboratory to be used/ chain of custody procedures:

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:
UIC Program Class VI Well Project Plan B-6 August 2012

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Additional Monitoring (if required by the UIC Program Director)

• Describe testing techniques and methods and their associated quality assurance and 

surveillance measures, testing frequency (e.g., anticipated test dates), and plans to record 

and report the results.

Attachments

Map showing monitoring well locations; boundary of geophysical survey areas

Monitoring well schematics 
Appendix C

Sample Template of an 

Injection Well Plugging Plan
UIC Program Class VI Well Project Plan 

C2 August 2012

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UIC Program Class VI Well Project Plan C-3 August 2012

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Appendix C: Sample Template of an Injection Well Plugging Plan

Facility Information 

Facility name:

Facility contacts (names, titles, phone numbers, email addresses):

Location (town/county/etc.):

Planned tests or measures to determine bottom-hole reservoir pressure:

Planned external mechanical integrity test(s):

Information on Plugs:

Plug #1 Plug #2 Plug #3 Plug #4 Plug #5 Plug #6 Plug #7

Diameter of Boring in 

Which Plug Will be Placed 

Depth to Bottom of Tubing 

or Drill Pipe 

Sacks of Cement to be 

Used (each plug)

Slurry Volume to be 

Pumped

Slurry Weight 

Top of Plug 

Bottom of Plug 

Type of Cement or Other 

Material 

Method of Emplacement 

(e.g., balance method, 

retainer method, or twoplug method)

Attachments:

Injection well construction plan/schematics showing depth to tubing stub, exposed formation 

intervals, casing diameters, depths, etc. 

Information on formations, depths to USDWs, etc. 

Schematic/drawings of the placement of all plugs. 
UIC Program Class VI Well Project Plan 

C4 August 2012

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Appendix D

Sample Template of a PISC and 

Site Closure Plan
UIC Program Class VI Well Project Plan 

D-2 August 2012

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UIC Program Class VI Well Project Plan D-3 August 2012

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Appendix D: Sample Template of a PISC and Site Closure Plan

Facility Information 

Facility name:

Facility contacts (names, titles, phone numbers, email addresses):

Location (town/county/etc.):

Pre- and Post-Injection Pressure Differential

Figure: Predicted pressure changes (pre-injection to the cessation of injection).

Source: AoR delineation modeling.

Predicted Position of the Carbon Dioxide Plume and Associated Pressure Front at Site 

Closure

Figure: Map showing the extent of the carbon dioxide plume and pressure front at site closure. 

Source: AoR delineation modeling.

Post-Injection Monitoring Plan

Ground Water Quality Monitoring

Monitoring well name/location/map reference:

Well depth/formation(s) sampled:

Parameter/Analyte Frequency

Aqueous and pure phase carbon dioxide

Total dissolved solids 

pH

Specific conductivity (SC)

Temperature 

Other parameters (e.g., major anions and cations; trace metals; 

tracers; hydrocarbons; and volatile organic compounds)

Sampling methods:

Analytical techniques:

Laboratory to be used/ chain of custody procedures:

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:
UIC Program Class VI Well Project Plan D-4 August 2012

Development Guidance 

Carbon Dioxide Plume and Pressure Front Tracking

Direct Pressure Monitoring

Well Location/Map Reference Depth(s)/Formation(s) Frequency

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:

Indirect Carbon Dioxide Plume and Pressure Front Tracking 

• Describe indirect methods to be used (e.g., types of indirect surveys to be performed, the 

planned areal extent/resolution of geophysical surveys, and planned frequency/schedule) 

and their associated quality assurance and surveillance measures, and plans to record 

and report the results.

Direct Geochemical Plume Monitoring

• If it is determined that direct geochemical monitoring of the plume is necessary, describe 

the locations where samples will be taken and parameters to be monitored.

Monitoring Location/Map Reference Frequency

Sampling methods:

Analytical techniques:

Laboratory to be used/ chain of custody procedures:

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:
UIC Program Class VI Well Project Plan D-5 August 2012

Development Guidance 

Surface Air and/or Soil Gas Monitoring (if required by the UIC Program Director)

Monitoring Location/Map Reference Frequency

Sampling methods:

Analytical techniques:

Laboratory to be used/ chain of custody procedures:

Quality assurance and surveillance measures:

Plan for guaranteeing access to all monitoring locations:

Additional Monitoring (if required by the UIC Program Director)

• Describe testing techniques and equipment and their associated quality assurance and 

surveillance measures, testing frequency (e.g., anticipated test dates), and plans to record 

and report the results.

Proposed Schedule for Submitting Post-Injection Monitoring Results 

Planned Testing/Monitoring Reporting Schedule

Ground Water Quality Monitoring Data e.g., quarterly

Carbon Dioxide Plume and Pressure Front 

Tracking Data

Direct Pressure Monitoring Data

Indirect Carbon Dioxide Plume and Pressure 

Front Tracking Data

Surface Air and/or Soil Gas Monitoring Data

(if required by the UIC Program Director)

Additional Monitoring Data (if required by 

the UIC Program Director)

Alternative Post-Injection Site Care Timeframe

Describe the alternative post-injection site care timeframe and the demonstration made

under 40 CFR 146.82(a)(18) if approved by the UIC Program Director. The 

demonstration of an alternative post-injection site care timeframe must meet the criteria 

under 40 CFR 146.93(c)(1). 

This description should also include the expected timing that the non-endangerment 

demonstration may be made and advanced schedules for PISC and site closure. 
UIC Program Class VI Well Project Plan D-6 August 2012

Development Guidance 

Non-endangerment Demonstration Criteria

Describe the criteria and conditions that will be used to demonstrate non-endangerment 

at the site. This may include the predicted AoR extent, injection formation pressures, 

information on USDWs within the AoR, and relevant monitoring results.

Site Closure Plan

Planned Remedial/Site Restoration Activities:

Describe plans for removing all surface equipment and restoring vegetation. 

Information on Plugs for Monitoring Well #1:

Plug #1 Plug #2 Plug #3 Plug #4 Plug #5 Plug #6 Plug #7

Diameter of Boring in 

Which Plug Will be Placed 

Depth to Bottom of Tubing 

or Drill Pipe 

Sacks of Cement to be 

Used (each plug)

Slurry Volume to be 

Pumped

Slurry Weight 

Top of Plug 

Bottom of Plug 

Type of Cement or Other 

Material 

Method of Emplacement 

(e.g., balance method, 

retainer method, or twoplug method)

Include additional tables for other monitoring wells.
Appendix E

Sample Template of an 

Emergency and Remedial 

Response Plan
UIC Program Class VI Well Project Plan 

E-2 August 2012

Development Guidance
UIC Program Class VI Well Project Plan E-3 August 2012

Development Guidance 

Appendix E: Sample Template of an Emergency and Remedial Response Plan

Facility Information 

Facility name:

Facility contacts (names, titles, phone numbers, email addresses): 

Location (town/county/etc.): 

List of Resources/Infrastructure 

• List/describe the resources and infrastructure that may be impacted by an adverse event 

(e.g., wells, USDWs, surface water bodies, sensitive nearby environments, structures). 

Indicate the potential for any scenarios to be of high impact, e.g., if all people in the area 

are served by a single drinking water source. 

Infrastructure/Resource-Specific Events and Response Plan

Describe the type(s) of adverse event(s) that may occur at each resource/infrastructure; whether 

the risk is considered to be high, medium, or low; and planned response actions, response staff, 

and equipment. Exhibit E-1 at the end of this appendix provides examples of potential adverse 

events and corresponding response actions at Class VI well sites.

Infrastructure: Injection well (map reference)

Potential adverse event #1: e.g., a well blowout

Risk level: 

Potential response action(s): 

Response personnel: 

Equipment: 

Potential adverse event #2:

Risk level: 

Available response action(s):

Response personnel: 

Equipment: 

Etc...

Resource: USDW

Potential adverse event #1:

Risk level: 

Available response action(s):

Response personnel: 

Equipment: 
UIC Program Class VI Well Project Plan E-4 August 2012

Development Guidance

Resource: [Name of municipality] water supply (map reference)

Potential adverse event #1: 

Risk level:

Available response action(s):

Response personnel:

Equipment:

Resource: [Name of surface water body] (map reference)

Potential adverse event #1: 

Risk level:

Available response action(s):

Response personnel:

Equipment:

List other applicable resources/infrastructure.

Staff Training and Exercise Procedures:

• Describe any such procedures. The description may include:

- Which staff are priority to receive the relevant training;

- What training materials or potential source of materials may be used; and

- What actions staff will be able to perform after receiving training.

Communications Plan and Emergency Notification Procedures:

• Emergency response contact(s) and role(s):

• Communication methods (e.g., Internet, newspapers, public service announcements): 

• Audience:

• Other contacts: e.g., local water systems, carbon dioxide source(s) and pipeline operators, 

land owners, other states or countries in the AoR, Regional Response Teams (Regional 

Response Teams represent geographic regions of the U.S. and are made up of 

representatives from federal agencies as part of the National Response Team).

Attachments: 

Safety and Health Plan

Map of the AoR showing resources and infrastructure 
UIC Program Class VI Well Project Plan E-5 August 2012

Development Guidance 

Exhibit E-1

Examples of Potential Adverse Class VI Events and Emergency Response Options

Adverse Event Potential Response Actions

Leaking well/Loss of 

mechanical integrity

o Stop injection and notify the UIC Program Director within 24 hours. 

o Repair the well by plugging it with cement. 

o Pull and replace the tubing or the packer.

o Create a hydraulic barrier by increasing reservoir pressure up-gradient of 

the leak.

o Install chemical sealant barrier to block leaks.

Well blowout

o Stop injection and notify the UIC Program Director within 24 hours. 

o Close the blowout preventer; insert rams into the well.

o Kill the well by pumping a fluid down the well bore that is heavier than 

the blowout fluid until the well stops flowing. 

o Drill another hole to intersect the well and pump fluid down.

Ground water 

contamination

o Stop injection and notify the UIC Program Director within 24 hours. 

o Pump carbon dioxide-contaminated groundwater to the surface and aerate 

it to remove carbon dioxide. 

o Apply “pump and treat” methods to remove trace elements.

o Drill wells that intersect the accumulations in groundwater and extract 

carbon dioxide. 

o Provide an alternative water supply if ground water-based public water 

supplies are contaminated.

Surface water 

contamination

o Stop injection and notify the UIC Program Director within 24 hours. 

o Shallow surface water bodies that have significant turnover (e.g., shallow 

lakes) or turbulence (e.g., streams) will quickly release dissolved carbon 

dioxide back into the atmosphere.

o Create a hydraulic barrier by increasing reservoir pressure upstream of 

the leak.

Leakage through faults 

and fractures

o Stop injection and notify the UIC Program Director within 24 hours. 

o Lower injection rates/pressures.

o Install chemical sealant barriers to block leaks. 

Accumulation of carbon 

dioxide in indoor air

o Stop injection and notify the UIC Program Director within 24 hours. 

o Manage potential slow indoor releases with basement/substructure 

venting or pressurization.

o Use fans to disperse carbon dioxide similar to radon fans.

Adapted from: World Resources Institute. CCS Guidelines: Guidelines for Carbon Dioxide Capture, 

Transport, and Storage. Washington DC. 2008. Table 8, p. 77. 
UIC Program Class VI Well Project Plan 

E-6 August 2012

Development Guidance
Appendix F

Checklist of Recommended 

Considerations for Evaluating 

Plans and Amendments
UIC Program Class VI Well Project Plan 

F2 August 2012

Development Guidance 
UIC Program Class VI Well Project Plan F-3 August 2012

Development Guidance 

Appendix F: Checklist of Recommended Considerations for Evaluating Plans and 

Amendments

Below is a checklist of questions and considerations that UIC Program Directors may use when 

evaluating the proposed project-specific plans and/or amendments.

Geology and Hydrogeology

• Geologic conditions, including structures and the type and number of subsurface 

formations: 

o The presence of faults and fractures, which may affect plume movement and 

containment.

o The presence of oil/gas/water, which may impact the feasibility of geophysical 

tests or necessitate monitoring for released hydrocarbons.

o The type, number, and thickness of subsurface formations between the lowermost 

USDW and the injection zone, which impact AoR model selection and 

assumptions and the amount of monitoring needed.

o Heterogeneity of the geologic stratigraphy, permeability, or other parameters, 

which impact AoR model selection and assumptions.

• Baseline geochemical and mineralogical data:

o The geochemistry of formations that are penetrated by the well, which may affect

compatibility with the injectate, ground water monitoring needs and the 

parameters to be analyzed, and corrective action and injection well plugging 

methods and the types of cement.

o Composition and mineralogy of the subsurface soil/rock matrix and the potential 

for mineralization reactions and porosity changes, which may impact ground 

water analysis. 

o Fluid pressures, horizontal and vertical gradients, and groundwater flow direction 

and velocity of subsurface formations, which impact AoR model selection and 

assumptions. 

o Multiphase flow parameters, and assumed relative permeability-saturation 

relationships and equations of state, which impact AoR model selection and 

assumptions.

• Hydrogeological data and USDWs:

o Proximity and depth to USDWs or other drinking water sources, which may 

necessitate additional monitoring.

o The presence of multiple subsurface layers with USDWs and the types of 

subsurface formations penetrated by the well, which may affect the placement of 

monitoring wells and injection well plugging and cement.

o If an injection depth waiver is sought, all USDWs above and below the injection 

zone must be addressed.
UIC Program Class VI Well Project Plan F-4 August 2012

Development Guidance 

Land Uses and Activities in the AoR 

• Land uses include population, sociological, and demographic considerations:

o Activities in the AoR, e.g., the presence of communities, residences, population 

centers, or buildings, which may drive monitoring needs.

o The pace of development or land use changes in the region, which may impact 

monitoring needs or AoR reevaluation schedules (e.g., if additional wells may be 

drilled, or abandoned, between AoR evaluations).

o Past and planned land use changes, which may affect the owner’s or operator’s 

ability to access monitoring sites or wells for corrective action.

o Proximity and depth to public water supplies or private wells, which may 

necessitate targeted monitoring and considerations for emergency and remedial 

response planning.

o Environmental justice concerns and potentially disproportionate impacts on health 

to a particular subpopulation (low income or minority) or children’s health.

o Public input and concerns. 

• Physical properties of the land due to human impacts:

o The presence of active and abandoned wells, which must be accounted for in AoR 

modeling, addressed in corrective action, and may impact monitoring locations.

o The presence (or planned presence) of other operators. Where multiple operators 

are involved, AoR models should account for pressure changes that may result 

from all injection operations in a formation or a series of hydraulically connected 

formations. 

o The presence (or planned presence) of mineral exploration, drilling, or abandoned 

wells, which can affect containment.

Injection Well/Operations

UIC Program Directors might consider several factors related to planned injection well 

operations:

• Carbon dioxide stream geochemistry:

o The potential for impurities in the carbon dioxide stream, e.g., based on the 

process generating the carbon dioxide and capture technologies. This can impact 

the potential degradation of well materials (and therefore corrective action 

methods and methods to plug the injection well) and carbon dioxide analysis 

needs.

o Whether the source of the carbon dioxide will vary over the life of the well.

Frequent changes in the carbon dioxide source or multiple sources may 

necessitate more frequent carbon dioxide stream analysis. 

o If the carbon dioxide will be injected on site or be piped/transported somewhere 

else for injection, which may result in contamination or mixing with water.
UIC Program Class VI Well Project Plan F-5 August 2012

Development Guidance 

• Operational data (e.g., injection rates and volumes) collected. This will affect the size of 

the AoR, and therefore, required corrective action, monitoring sites, and the resources/ 

infrastructure to address in the Emergency and Remedial Response Plan. 

• The AoR model/predicted size and extent of the carbon dioxide plume: 

o The anticipated size and shape of the AoR, which would affect monitoring 

locations and the areal extent of geophysical surveys, and the resources/ 

infrastructure to address in the Emergency and Remedial Response Plan. 

o The anticipated rate of plume movement and which wells will be intersected by 

the carbon dioxide plume and pressure front, which will affect AoR reevaluation 

and corrective action schedules. 

o Confidence in the assumptions that will be used for AoR delineation or the 

general modeling approach. Significant uncertainties in AoR delineation 

modeling may be addressed by more frequent reevaluation and comparison to 

monitoring data, particularly early in the project. 

Additional Considerations for AoR Reevaluations and Plan Amendments

• Evidence of leaching/mobilization of metals, organics, etc., which may indicate a need to 

change ground water monitoring parameters.

• Indications that the carbon dioxide plume is moving faster than predicted or in a different 

direction, which may warrant more pressure monitoring (i.e., in more locations) or more 

frequent geophysical surveys and AoR reevaluation. 

• Comparison of model results and monitoring data. If the original model (or the previous 

AoR model) does not closely match monitoring results, or if there was a significant 

change in results from the last modeling run, the modeling assumptions may need to be 

revised or additional inputs may be needed. 

• MIT results that may indicate concerns about the well.

• Any significant changes to the facility, e.g., to injection volumes or the number of wells. 

• If there are new owners or operators in the AoR or new mines or other subsurface land 

uses. 

• If recent (or planned) land use changes brought new receptors or infrastructure near/into 

the AoR. 

• If there has been a need to implement emergency procedures or any of the considered 

emergency scenarios are more likely to occur than originally considered. 
UIC Program Class VI Well Project Plan F-6 August 2012

Development Guidance 

Sources of Additional Information 

Final Class VI Rule and Preamble. Available on the Internet at:

http://water.epa.gov/type/groundwater/uic/wells_sequestration.cfm).

Environmental Protection Agency (EPA) Class VI Rule Guidance documents. Available on the 

Internet at: http://owpubauthor.epa.gov/type/groundwater/uic/class6/gsguidedoc.cfm. 

Emergency Planning and Community Right-to-Know Act (EPCRA) Local Emergency Planning 

Requirements. Available on the Internet at:

http://www.epa.gov/emergencies/content/epcra/epcra_plan.htm. 

EPA Office of Emergency Management. Available on the Internet at:

http://www.epa.gov/emergencies. 

EPA. 2008. Vulnerability Evaluation Framework for Geologic Sequestration of Carbon Dioxide. 

EPA 430-R-08-009. July 10. 

EPA. 2010. Technologies Available to Address Induced Faults and Fractures: Considerations for 

GS Sites. 816-R10-0018. 

EPCRA Emergency Release Notification Requirements. Available on the Internet at:

http://www.epa.gov/OEM/content/epcra/epcra_report.htm. 

Homeport: U.S. Department of Homeland Security, U.S. Coast Guard. Available on the Internet 

at: http://homeport.uscg.mil/mycg/portal/ep/home.do. 

National Oil and Hazardous Substances Pollution Contingency Plan Overview. Available on the 

Internet at: http://www.epa.gov/OEM/content/lawsregs/ncpover.htm. 

National Response Team. Available on the Internet at:

http://www.epa.gov/OEM/content/partners/nrsrrt.htm. 

Regional Response Teams. Available on the Internet at:

http://www.epa.gov/OEM/content/partners/nrsrrt.htm; 

http://www.epa.gov/OEM/content/nrs/nrsworks.htm. 

Requirements for Oil Facility Response Plans. 33 CFR Part 154 subpart F. 

World Resources Institute. CCS Guidelines: Guidelines for Carbon Dioxide Capture, Transport, 

and Storage. Washington DC. 2008.