From: "Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>

To: Sharon Nizich/RTP/USEPA/US@EPA

Cc: Steve Fruh/RTP/USEPA/US@EPA

Date: 08/03/2010 05:47 PM

Subject: Part of E.O. 12866 Review: Interagency Discussion about the revised RIA pertaining to NESHAP: 

Mercury Emissions from Mercury Cell Chlor-Alkali Plants 2060-AN99

Hi Sharon,

Attached is a document with the interagency comments received so far. I anticipate additional 

comments, especially on the RIA, but I'd like to use the time tomorrow to discuss the RIA.

We will also be sending suggested language on the mercury health effects, but it is not yet ready. When 

characterizing methylmercury health effects, the language is different between RIA and the preamble. 

Can you explain where the preamble language came from?

Please let me know if you have any questions.

Regards,

Cortney

202.395.7856

(See attached file: InteragencyWorkingCommentsonEPA_HgChlorAlkali_EO12866Review_08032010.pdf)
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

EO12866_Mercury Emissions from Mercury Cell Chlor-Alkali Plants 2060-AN99 NPRM RIA_20100803

Interagency Working Comments on Draft Rule under EO 12866 8/3/2010 

Below are additional working comments from the interagency review of the draft rule titled, “NESHAP: 

Mercury Cell Chlor-Alkali Plants, Amendments.” 

General Comments: 

1) Page 15: It is not clear why the detection limit is set at or below 0.5 times the mercury concentration 

measured during the test. What is the basis for the 0.5 factor? 

2) Page 17: IV A refers to the proposal of a zero mercury standard although this is contradictory to what 

is stated on page 13 in that zero mercury emissions are noted as “impossible”. Rather, this is a 

proposal for conversion to non-mercury technology or closure of existing mercury technologies. We 

suggest this header be reworded to better reflect what the proposal is about. A similar statement of a 

“zero mercury standard” is on page 32 and we suggest this be revised. 

3) Page 19: Consider inserting a paragraph describing mercury cell technology before the paragraph 

beginning, “Conversion from mercury cells to membrane cells...” 

4) Page 29: Can you provide more information about “the data” that plant closure may be the owner’s 

preferred option? 

5) Page 29: Mercury is described from industrial sources and from mercury cell chlor-alkali plants. 

Please clarify the “industrial sources” by providing examples and clarify liquid, particulate, and vapor 

states for the different species from “industry” and from the chlor-alkali sector to make this section 

more descriptive for the general reader. 

6) Page 30: Can EPA be more specific about the predominant types of Hg emitted by these factilities in 

the following statement? Furthermore, can EPA explain the basis for the 12 month residence time 

given for mercury in circulation within the global pool? “Mercury that is emitted can be 

atmospherically transported different distances depending on the species. While inorganic mercury is 

generally transported relatively short distances before depositing, elemental mercury, barring any 

topographical interferences, can enter the global pool and remain in circulation up to 12 months prior 

to deposition.” 

7) Has EPA considered quantifying the social benefits of reduced energy demand by using the social 

cost of carbon (http://www.epa.gov/otaq/climate/regulations/scc-tsd.pdf)? Reduced energy demand 

will result in reduced carbon emissions from power plants, and such reductions can be estimated, 

using the social cost of carbon, to quantify the social benefits. We suggest using the annual emissions 

from a 40 megawatt power plant, multiplied by the social cost of carbon, to estimate social benefits. 

8) Page 34: Can EPA provide a list/information on examples of rules where the beyond the floor costeffectiveness of mercury control has been similar to what is in this rule. 

RIA 

9) The energy savings co-benefits are described in Chapter 5, and more information is found in 

Appendix B. Can EPA provide the “XL” sheet referenced in the Appendix, as well as 

information the COBRA model? Furthermore, what is the source of these emissions factors? 

“EPA’s eGrid database provided emission factors for NOX, SO2, CO2, and Hg (see attached 

XL spreadsheet). RTI calculated emission factors for pollutants for which EPA’s eGrid data 

was unavailable. The Co-Benefits Risk Assessment model (COBRA) provided total 

emissions estimates by fuel type and by pollutant for 2010.”

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