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

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|Melanie King/RTP/USEPA/US

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

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|Fred Talcott/DC/USEPA/US@EPA

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|08/10/2010 01:28 PM

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|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

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

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|Melanie King/RTP/USEPA/US@EPA

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|08/10/2010 11:27 AM

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|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.”

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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.”