MEMORANDUM

Date: November 1, 2011

Subject: Summary of discussion from the October 21, 2011, meeting between the 

Sierra Club and the Environmental Protection Agency on the Oil and 

Natural Gas Risk and Technology Review

From: Greg Nizich, EPA/OAQPS/SPPD/FIG

To: EPA Docket ID: EPA-HQ-OAR-2010-0505

I. PURPOSE

This memorandum summarizes the October 21, 2011 tele-conference between the 

Environmental Protection Agency (EPA) and representatives from the Sierra Club. The purpose 

of this call was to listen to comments and concerns from the Sierra Club regarding the August 

23, 2011, Oil and Natural Gas Sector proposed rules.

II. DATE

The call took place between 1:00 pm and 2:30 pm on October 21, 2011 at the Research 

Triangle Park, NC, campus of the U.S. EPA.

III. ATTENDEES

The following individuals attended the tele-conference:

Sierra Club

Emma Cheuse

Devorah Ancel

National Resources Defense Council

Miriam Rotkin-Ellman

Avi Kar

Clean Air Task Force

Praveen Amar 

Bruce Buckheit
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U.S. Environmental Protection Agency 

Bruce Moore

Greg Nizich 

Mark Morris

IV. SUMMARY OF DISCUSSION

Bruce Moore began the meeting by saying that since the discussion was taking place between 

proposal and promulgation, EPA cannot respond to comments, but can listen to the issues raised 

during the meeting and provide clarifying information. The following is a summary of the topics 

raised by the Sierra Club:

1) Emissions Data and sources used other than the 2005 National Emissions Inventory (NEI) 

data. Concern that 2005 data isn’t representative with recent increases in oil and natural gas 

production. The Sierra Club asked about other studies that were compared to NEI data.

2) An observation that certain pollutants were removed from the NEI data for the source

category. EPA stated that certain sources were removed from the data base if they were not part 

of the source category (e.g., internal combustion engines). 

3) Risk Analysis – Other carcinogens evaluated in addition to the risk driver. EPA stated that the 

docket contains all risk modeling inputs, and the risk report contains summary output 

information for each facility, as well as the cancer driver for the MIR, and incidence drivers. 

The inputs could be examined to see which HAP were modeled. EPA clarified that the docket 

does not contain complete modeling output data for each facility. A cancer risk-driver file that 

gives the cancer risk drivers for each facility is not in the docket. A need for a summary of

cancer risk across the sector was also expressed. 

4) Concern with emissions of hydraulic fracking compounds and that 25-28 hazardous air 

pollutant (HAP) compounds are listed in a government report.

5) EPA should be addressing other emission points other than dehydrators, storage vessels and 

leaking equipment. 

6) The 10% VHAP exemption and the affected facility definition in subpart OOOO needed 

further revision. 

7) A need for additional information concerning the table of emission points for facilitywide risk 

and how those values were calculated. 

8) Clarification in the MACT allowable assessment whether only emissions of benzene are 

increased or if other HAP are increased proportionately too. 

9) Clarification if naphthalene is considered in the multi-pathway assessment. 
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10) A question whether the acute risk analysis used MACT allowable emissions too. EPA said it 

did not due to the conservative approach for the acute assessment.

11) A comment that the residual risk table lists cancer drivers, but that there are some 

compounds listed such as xylene and toluene that shouldn't be there. EPA agreed.

12) A request for clarification in the transmission and storage (i.e., 40 CFR 63 subpart HHH) risk 

discussion regarding EPA’s explanation of the risk reduction of the MIR from 90 to 20-in-1-

million. The Sierra Club referred to Table 3 in the docket item ending in 0077, the technical

review memo for MACT. 

13) A question about the multi-pathway assessment period of 50 yrs. vs. the 70 yrs. for cancer

assessment. EPA stated that it assumes a facility emits for 50 years for the purposes of the multipathway modeling. 

14) The use of emissions of BTEX as a surrogate for regulated HAP for small glycol 

dehydrators. EPA believed that only complete emissions data for BTEX was in our dataset and 

that reduction of BTEX would result in corresponding reductions for other HAP. 

15) The MACT review for new LDAR sources should be based on a BACT determination in 

EPA’s RBL Clearinghouse for valves. 

16) A question concerning the dollars/ton of emission reduction being the decision criteria and 

not other metrics that might include risk-based factors.

17) Concerns that the existing excused excursion language in sections 63.773(d) and 63.1283(d)

conflicts with the removal of startup, shutdown and malfunction provisions in other sections of 

the proposed rules. 

18) A question about why different meteorological data wasn’t used. EPA stated that the most 

appropriate data available for a given location is used. 

19) A comment regarding exposure to children below a certain age.