Interagency Working Comments on Draft Rule under EO 12866 8/2/2010 

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

“National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal 

Combustion Engines--Existing Stationary Spark Ignition (Gas-Fired).” 

Comments: 

 Limited Use Engines: Can EPA explain why limited use engines only includes start up 

combustion turbines? For instance, there are limited use nonemergency SI engines, just 

as there were in the CI Rule. Some of these are operated only periodically – some 

transmission lines include small stations that run very infrequently – i.e., only operate 

when there is significant gas demand (or for routine engine checks) and may not run at 

all or only a few hours in some years. These should be treated as emergency engines – 

there will be more time spent on testing/evaluation than there may be operating. 

o A commenter suggests a broader definition for limited use engines or state why 

EPA isn’t at this time providing more relief for other limited use engines. 

o Also suggested is one time testing for these engines, rather than more frequent 

testing. 

 Limited Use Engines: A commenter adds that given that EPA is already re-considering 

limited use nonemergency CI engines, in response to requests for reconsideration, EPA 

should state that it is reconsidering this issue and should specifically solicit comments on 

how to handle nonemergency limited use engines – CI and SI, so that it can better 

formulate a new proposal, going forward. 

 Cost of Control: I’ve been able to determine that EPA used the annual cost of testing 

(p.4 , June 29th EC/R memo) as part of the total annual cost (TAC). This, I believe, is 

due to the fact that EPA assumes annual catalyst washing and replacement, which 

triggers an additional performance test – so that there are three tests in every three 

years, instead of one. For the major sources, since there are annual testing costs in the 

major source floor baseline, TAC is not included in the annual cost for the above the 

floor calculation. However, as a practical matter, the additional annual cost of testing of 

$3946 testing/monitoring etc. per year is still part of the cost of achieving the incremental 

cost of achieving the emission reductions for the 4 SRB 300-500 HP major source 

engines, and EPA should not eliminate this incremental cost because it is part of the 

floor costs. This is true because EPA states that there are no incremental emission 

reductions in the floor, so EPA would be properly reporting the incremental costs over 

the status quo if it included ATC. Thus, EPA underestimates the major cost above the 

floor annual costs by approximately $3946/year using this protocol. 

o A commenter suggest that EPA should apply the additional $4000/year 

testing/monitoring etc. cost to both major and area source calculations for 

4SRBs, and not to area sources alone, which EPA appears to have done. 

 Annual Testing Costs: 
Interagency Working Comments on Draft Rule under EO 12866 8/2/2010 

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o Can EPA clarify the source of the documentation of the testing/monitoring etc. 

annual cost of $3,946 (found in the SI Engine Control Cost and Cost per Ton 

Summary Spreadsheet). Since the test itself is $1000/engine, what is the basis 

for the remaining monitoring/recordkeeping etc. being $2,946? 

o Does EPA agree that it should also include the $4000/year ATC cost to major 

source calculations as part of the 4SRB cost effectiveness calculation since the 

status quo now reflects no regulation of existing engines? 

 Requirement to Monitor Pressure and Temperature – Oxidation Catalysts and 

NSCRs: Comments from OIPA included the following statement: “EPA proposes that 

operators monitor the pressure drop across the catalyst and the temperature of the 

exhaust so they meet the proposed operating limitations for RB engines. Again, most 

crude oil and natural gas facilities are located in remote, rural areas, sometimes many 

hours from the home or field offices. Many of the facilities do not have electricity to 

monitor or record exhaust temperature or the pressure drop across the catalyst. We 

don’t think EC/R has accounted for running electricity to a facility and request this cost 

be included in the analysis.” 

o Can EPA explain how they addressed this comment? We suggest removing this 

requirement for remote facilities. 

 Hourly Meters: Comments from OIPA included the following statement: “According to 

the preamble, existing engines located at area sources that are subject to management 

practices are required to record fuel consumption and hour data shown on the hour 

meters. Typically, in Oklahoma, natural gas produced from the well is used to run the 

engines at the facility, and there are no meters installed to record fuel consumption. To 

determine fuel usage for small engines like pump jacks, operators typically use the 

manufacturer’s data to calculate that information. The requirement to install a fuel meter 

will only increase capital, maintenance, and replacement costs without any 

environmental benefit. Also, hour meters are not installed on these types of engines 

either. In addition, EPA does not specify the frequency that this data is to be kept i.e. 

hourly, weekly, monthly, etc. The proposed requirement will be unnecessarily costly and 

burdensome on small businesses and those companies that operate marginal crude oil 

and natural gas wells that operate on the lower edge of profitability. We request EPA 

remove these requirements for engines less than 500 HP that are located at area 

sources.” 

o Can EPA explain how they addressed this comment? 

Previous RIA comments: 

RIA 

1) The RIA should include the summary of analysis of regulatory alternatives. A table to 

allow comparison of analyzed alternatives would be helpful to show compliance with EO 

12866 and Circular A-4 
Interagency Working Comments on Draft Rule under EO 12866 8/2/2010 

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2) The exec summary should briefly describe what the rule does. Suggest that Chap 4 

first paragraph be coped to Exec Summ to briefly describe the what the rule does, followed 

by first two paragraphs in 4.2.2. 

3) Could EPA please insert some brief description of the regulated objects and how they 

are used, both in the Exec Summary and also the beginning of Chapter 3 (which 

discusses the industries, but now the equipment)? 

4) Early in the document, including both Exec Summ and early in both cost and benefit 

chapters, the RIA should provide a bulleted list of uncertainties associated with the 

analysis and assumptions required to develop these estimates. 

5) Since there are no NOx reductions for the MACT floor, the reference to non-monetized NOx 

reductions should be removed from Table 1-1 and any other table that presents a summary 

of the benefits for the MACT floor. 

6) The RIA should outline how estimates of benefits-per-ton were developed, including 

the source of the key analytic inputs, assumptions, and uncertainties. The current 

draft does not explain the tons reduced, whether all sources are assumed to the same, how 

precursors are related to PM concentrations, and how estimates take into account the 

tremendous geographic diversity in population density etc. Is there a description 

somewhere that can help the reader navigate how EPA modeled or measured PM from 

precursors? Throughout, it is difficult to identify how EPA separately analyzed emitted PM, 

PM formed from precursors, and gaseous SOx or NOx. 

7) Could EPA please clarify that only PM benefits are quantified, and that they are 

quantified by precursor? Particularly in the labeling of charts and graphs.

8) P 3-1 What is the significance of years 2002 and 2007 in the second paragraph of 

3.1.1? The choice of specific years without reference to what happened prior to those years 

or between seems random, particularly since figure 3-1 seems to show a possible trend 

flattening in the later years. 

9) Suggest Figure 3-2 should show values, not just bubbles.

10) P 3-5 reads “In less regulated companies ...” does EPA mean to say “fewer ... than”, 

or is the intent of the sentence to refer to the mathematical operation (2% less a value 

that is unclear