----- Forwarded by Melanie King/RTP/USEPA/US on 08/10/2010 02:31 PM

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>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Melanie King/RTP/USEPA/US |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | To: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |"Higgins, Cortney" <Cortney_Higgins@omb.eop.gov> |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Cc: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Fred Talcott/DC/USEPA/US@EPA |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Date: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |08/10/2010 01:28 PM |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Subject: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Re: some interagency edits so far |

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Hi Cortney, On the comment on the text on p. 30, we will add "including data that was not used in the proposal" to the end of that quoted text. On the comment on the text on p. 42, we do not think it should be changed. The point we are trying to make is that the vast majority of area source engines are subject to management practices so the vast majority of the rural engines at area sources are subject to management practices. Unless Kevin has some data to show that rural area source engines are all 4SLB/4SRB >500 HP, I see no reason to change the language there.

Melanie King Energy Strategies Group Sector Policies and Programs Division Office of Air Quality Planning and Standards U.S. Environmental Protection Agency

Mail Code D243-01 RTP, NC 27711

Phone: (919) 541-2469 Fax: (919) 541-5450 king.melanie@epa.gov

|------------> | From: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |"Higgins, Cortney" <Cortney_Higgins@omb.eop.gov> |>---------------------------------------------------------------------------

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>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Melanie King/RTP/USEPA/US@EPA |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Date: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |08/10/2010 11:27 AM |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Subject: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |some interagency edits so far |

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p.30 – Cited text pasted in below. No one has suggested that EPA not base the MACT floor on emission results – others would question EPA’s new choice of data to represent the top 12% 100-500 HP 4SLB engines. The proposal was also based on emissions data, so that is not a valid distinction. Why does that test data now include controlled engines? EPA should refer to the “inadvertent omission” discussion on page 46 – or explain it in another matter here.

“EPA is also not using the Population Database to determine a percentage of engines that have emission controls installed, as it did at proposal. The Population Database has not been updated since 2000. It contains information regarding whether or not an engine has emission controls, but does not generally contain other types of emission-related information, like engine-out emissions or operational controls, and it does not include any emissions concentration data, which is necessary to determine the MACT floor. EPA determined that it would be more appropriate and more defensible to base the MACT floor analysis directly on the emissions data that EPA has for stationary SI engines.”

------------------------------------------------- p. 42 – Cited text pasted in below – EPA’s requirement of management practices on OTHER ENGINES in no way provides relief to owners with engines in RURAL AREA SOURCES. This irrelevant discussion should be deleted in its entirety. (We also disagree with the contention that rural and urban retrofit/testing costs are equivalent under GACT – but choose not to argue with EPA over this point.)

“EPA has taken steps in the final rule that reduce the burden on owners and operators of engines regulated in this final rule. EPA has established management practice standards for most of the engines located at area sources of HAP. The only existing stationary SI RICE at area sources that are required to meet numeric emission limitations are 4SLB and 4SRB non-emergency stationary SI RICE that are greater than 500 HP and operate more than 24 hours per calendar year; these engines are estimated to be only 7 percent of the population of existing SI RICE at area sources. EPA believes that requiring management practices instead of specific emission limitations and/or control efficiency requirements on the vast majority of existing stationary SI engines at area sources alleviates concerns regarding costly and burdensome requirements for rural sources.”