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.Document ID: EPA

- HQ

- OW

- 2008

- 0390

- 0120

Last Name: Spencer

First Name: Homer

Title: P. Eng.

Organization: Canitron Systems Inc.

City: Calgary

State: AB

Phone Number: (403)259

- 8732

Current Category Code: 256

Comment: For the past four years, our company has been field testing our proprietary systems and methods for

utilizing a low melting point fusible metal alloy to mold in situ plugs in wells to repair gas leakage problems. Our

focus has been on repair of vent gas flows that occur because of channels that exist within the cement

surrounding production casing in wells. Our field tests have been carried out wi th permission of the Alberta

Energy Resources Control Board ("ERCB") and under their scrutiny. We presently have a proposal under

consideration by the ERCB and the Canadian Association of Petroleum Producers (CAPP) to add our methods to

the approved well a bandonment protocols presently under review in Alberta.

We believe our methods are directly applicable to the problem of long term leakage of sequestered GHG from

wells that penetrate a reservoir used for the sequestration. Obviously, it makes neither eco nomic nor

environmental sense to capture, concentrate, compress, deliver, and inject CO2 into depleted reservoirs or

saltwater formations if there is not a reliable sealing method used on existing wells in that reservoir to prevent

the CO2 leaking back int o the atmosphere. We believe that our plugging methods can assure long term success

in preventing this leakage.

We use an alloy of bismuth and tin for our sealing medium. This alloy is non

- toxic and will not corrode or cause

corrosion in the relevant wel l environment from either chemical or galvanic processes. We believe we can seal a

well against gas flow even if the well casing has been entirely corroded away. The important properties of the

alloy that cause it to be effective are:

1) it expands about 1% by volume when solidifying from the liquid phase; 2) it is impermeable to gas flow; 3) it

seals effectively in dirty oily casing; 4) it has a high specific gravity to facilitate displacement of other fluids

present during the deployment process; and 5) it has a very low viscosity and surface tension such that it will

enter small fissures, and absorb into and wet permeable rocks such as sandstone.

Only small amounts of the alloy are required to form a seal with the d ifferential pressure strength required to

seal GHG sequestration wells. We set the plugs using an electric heater deployed on a wire line. The procedure is

both fast and inexpensive. We have data to back the above contentions, including corrosion tests car ried out in

a CO2/saltwater environment with a pH of 3 that indicate plug life in steel casing in excess of 10,000 years.

Regards,

Homer Spencer

P.Eng.

Canitron Systems Inc.

Calgary, AB, Canada

Ph/Fax: (403)259

- 8732

Cell: (403)616

- 5247Letter ID: 0120

Commenter: Homer Spencer

Organization: Canitron Systems Inc.

Letter ID: 0120 Comment ID: 22071 Letter Lines: 15 to 53

Comment Code: 1310 1.1.2.4 Comments on other "out of scope" issues, e.g., pore space

ownership

Comment Code: 1350 1.1.3.3 Comments on the need for GS technology

Comment Code: 3460 2.2.2.3 Acceptable corrective action techniques for GS sites (e.g.,

cements)

Comment: For the past four years, our company has been field testing our

proprietary systems and methods for util izing a low melting point fusible metal

alloy to mold in situ plugs in wells to repair gas leakage problems. Our focus

has been on repair of vent gas flows that occur because of ch annels that exist

within the cement surrounding production ca sing in wells. Our field tests have

been carried out with permission of the Alberta Energy Resources Control Board

("ERCB") and under their scrutiny. We presently have a proposal under

consideration by the ERCB and the Canadian Association of Petroleum Producers

(CAPP) to add our methods to the appr oved well abandonment pr otocols presently

under review in Alberta.

We believe our methods are directly applicable to the prob lem of long term

leakage of sequestered GHG fr om wells that penetrate a reservoir used for the

sequestration. Obviously, it makes neither economic nor environmental sense to

capture, concentrate, compress, deliver, and inject CO2 into depl eted reservoirs

or saltwater formations if there is not a reliable sealing method used on

existing wells in that reservoir to pr event the CO2 leaking back into the

atmosphere. We believe that our plugging methods can assure long term success in

preventing this leakage.

We use an alloy of bismuth and tin for our sealing medium. Th is alloy is nontoxic and will not corrode or cause corro sion in the relevant well environment

from either chemical or galvanic pro cesses. We believe we can seal a well

against gas flow even if the well casing has been entirely corroded away. The

important properties of the alloy that cause it to be effective are:

1) it expands about 1% by volume when so lidifying from the liquid phase; 2) it

is impermeable to gas flow; 3) it seals e ffectively in dirty oily casing; 4) it

has a high specific gravity to facilitate displacement of other fluids present

during the deployment process; and 5) it has a very low viscosity and surface

tension such that it will enter small fissures, and absorb into and wet

permeable rocks such as sandstone.

12 Only small amounts of the alloy are re quired to form a seal with the

differential pressure strength required to seal GHG sequestration wells. We set

the plugs using an electric heater depl oyed on a wire line. The procedure is

both fast and inexpensive. We have data to back the above co ntentions, including

corrosion tests carried out in a CO2/saltwat er environment with a pH of 3 that

indicate plug life in steel cas ing in excess of 10,000 years.

Individual Response: EPA thanks the commenters for the information on available well

materials. EPA believes that the regulation affords owners or operators flex ibility to use various

materials and techniques to pe rform corrective action, provided th ey meet with the Director's

approval.