This comment letter response contains two parts:   

(1) The original submittal from the commenter.

(2) A data base printout of EPA’s response to each point raised by the commenter.

Notes about the response letters:

• The response letters were generated by a data base used to track the content of all public

comment submittals and ensure that the Agency responds to each. Each comment letter

was assigned a Letter ID that corresponds to the last four digits of the docket number of the

original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA‐assigned comment code; and an

individual response. These are described and explained below.  

• The data base contains Comment text from the letters submitted by commenters.  

Many hard copy letters were scanned into electronic format for inclusion in the data

base. As a result, there may be some typographical errors attributable to optical

character recognition issues.  However, all original submittals were reviewed in the

process of drafting responses to ensure that the comment content was understood and

appropriately addressed.

• The content of each comment letter was divided into topic areas and assigned a unique

Comment ID.  Additionally, one or more Comment Codes (i.e., unique topic area ID) was

assigned to each discrete point raised by a commenter. This information was added to

the data base. To inform final rulemaking decisions, all comments and information

received on a given topic were reviewed by technical experts in each rule area (e.g., on

construction requirements).  

• Following decisions on the final rule requirements, Individual responses were drafted

by topic area to ensure completeness and consistency of the responses with the final

rule and other responses to similar comments.  Each discrete point made by a

commenter was given a unique response.

• Upon completion of comment responses, all information was entered into the data base.

Each letter response is a compilation of each comment and its individual response,

compiled in the order of the original comment letter.  As a result of this process, there is

repetition in the response text.  The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.   

• All comments in a topic area were reviewed, evaluated, and responded to concurrently.  

Responses on each topic area are compiled and are also available in the rulemaking docket.
Cynthia C. Dongherty 

Director, Office of Ground Water and Drinking Water 

U. S. Environmental Protection Agency 

1200 Pennsylvania Ave., NW. 

Washington, DC 20460 

Re: Proposed Rule for Geologic Sequestration of Carbon Dioxide 

Docket ID No. EPA-HQ-OW-2008-0390 

Dear Director Dougherty: 

March 27, 2009 

On March 17,2009, Environmental Defense Fund (EDF) and Clean Air Task Force (CATF) wrote separate 

letters to you reaffirming the importance of suggestions we submitted on December 23, 2008 as part of the 

group generally known as the Multi-Stakeholder Group (MSG). We hoped that you would distribute copies 

of our March 17 letters to the EPA workgroup convened for this docket if yon thought that distributing the 

letters would be appropriate. 

One of the subjects discussed in both the December 23 MSG letter and the March 17 ED F and CA TF 

letters is the importance, for Safe Drinking Water Act purposes, of: (1) drawing a "bright line" between two 

different types of C02 injection projects in oil and gas fields; and (2) more clearly distinguishing injection 

projects in oil and gas fields from injection projects in brine formations. As explained in the letters, we 

believe there are three different types of C02 injection activity that present three different risk profiles and 

ought to be regulated in three different ways. We asked that the Agency solicit public comment on this 

subject as part of a NODA process. 

While the December 23 and March 17 letters discussed in a general way this three-fold approach to 

managing the risks of C02 injection, and while the December 23 letter suggested "bright line" language we 

believe should be used to distinguish between the two types of injection projects in oil and gas fields, none 

of these letters set forth language that might be used to regulate the type of oilfield project that poses higher 

risk to the environment. We are aware that other MSG participants arc forwarding to you today language 

that might be used for this purpose in Class II or in a new Class VII. We expect to support portions of this 

language and recommend changes in other portions. In order to move the process forward, however, we 

urge you to publish the language for public comment as part of the contemplated NODA. EDF and CATF 

will continue to work with other MSG participants on the issue and look forward to the opportunity to 

make detailed comments on this subject in the future. 

Sincerely, 

A. Scott Anderson 

Senior Policy Advisor 

Environmental Defense Fund 

Kurt Waltzer 

CCS Development Coordinator 

Clean Air Task Force 
Letter ID: 0296 

Commenter: A. Scott Anderson 

Organization: Environmental Defense Fund 

Letter ID: 0296 Comment ID: 29476 Letter Lines: 29 to 58 

Comment Code: 2046 1.5.2.3 Continuing to classify CO2 injection for EOR/EGR as Class II/ 

dividing line between Class II and Class VI (seeking comment) 

Comment: On March 17,2009, Environmental Defense Fund (EDF) and Clean Air Task Force 

(CATF) wrote separate letters to you reaffirming the importance of suggestions 

we submitted on December 23, 2008 as part of the group generally known as the 

Multi-Stakeholder Group (MSG). We hoped that you would distribute copies of our 

March 17 letters to the EPA workgroup convened for this docket if you thought 

that distributing the letters would be appropriate. 

One of the subjects discussed in both the December 23 MSG letter and the March 

17 EDF and CATF letters is the importance, for Safe Drinking Water Act purposes, 

of: (1) drawing a "bright line" between two different types of CO2 injection 

projects in oil and gas fields; and (2) more clearly distinguishing injection 

projects in oil and gas fields from injection projects in brine formations. As 

explained in the letters, we believe there are three different types of CO2 

injection activity that present three different risk profiles and ought to be 

regulated in three different ways. We asked that the Agency solicit public 

comment on this subject as part of a NODA process. 

While the December 23 and March 17 letters discussed in a general way this 

three-fold approach to managing the risks of CO2 injection, and while the 

December 23 letter suggested "bright line" language we believe should be used to 

distinguish between the two types of injection projects in oil and gas fields, 

none of these letters set forth language that might be used to regulate the type 

of oilfield project that poses higher risk to the environment. We are aware that 

other MSG participants are forwarding to you today language that might be used 

for this purpose in Class II or in a new Class VII. We expect to support 

portions of this language and recommend changes in other portions. In order to 

move the process forward, however, we urge you to publish the language for 

public comment as part of the contemplated NODA. EDF and CATF will continue to 

work with other MSG participants on the issue and look forward to the 

opportunity to make detailed comments on this subject in the future. 

Individual Response: EPA clarifies that the GS rule does not change the requirements or 

address Class II EOR operations. EPA believes that injection of CO2 for the primary purpose of 

enhancing oil and gas recovery should remain under the Class II Program. EPA believes that the 

nature and risks of CO2 injection for the primary purpose of long term storage poses different 

risks than injection for the primary purpose of EOR, and therefore has developed new Class VI 

1 
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regulations to address these unique risks. For example, the volume of CO2 anticipated to be 

injected for long term storage is significantly greater than for ER operations. Reservoir pressure 

conditions will also be different, with Class VI injection operations involving large volumes of 

CO2 and likely having higher pressures within their storage formations than Class II EOR 

projects. 

The final Class VI regulations require that any owner or operator injecting CO2 for the primary 

purpose of long term storage obtain a Class VI permit with some special consideration for the 

fact that they are transitioning from a well not originally designed to meet Class VI requirements. 

The Director has the authority to determine at what point a Class VI permit is required for those 

projects that are transitioning from the primary purpose of EOR to long term storage of CO2. 

The final regulation provides a set of technical factors for the Director to evaluate in making this 

determination, at §144.19. EPA believes that this approach provides sufficient protection of 

USDWs when there is an increased risk to USDWs as compared to traditional Class II operations 

while allowing for site-specific flexibility. For more information, please see the discussion on 

transition of Class II wells in the preamble to the final GS rule.