From:•Antonio Santos [asantos@meca.org]

Sent:•Tuesday, April 20, 2010 6:05 PM To:•Tanya Parise Subject:•RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines Hi, Tanya. Just received another reply today (see below). Antonio

--- Engines less than 500 hp - My best estimate would be 20-30 % (not too sure of total engine counts in operation); however, I am seeing that many of the packagers of the small engine compressors are now including catalysts. There are still a large number of engines in the field that do not have engine aftertreatment. Engines larger than 500 hp - I would estimate 80-90% have aftertreatment; however, I would like to mention that most engines I come across are 750 hp and larger. I do not see many 500 to 750 hp engines in use. And, finally, I don't think there will be any difference from major source or area source. What I have found is that on larger engines many operators (such as DCP Midstream) have taken a pro-active approach and have had catalysts on the engines for years throughout their fleet. And the small engine packagers are now including this as part of the packages in preparation for the NESHAP for SI engines.

-----Original Message----- From: Tanya Parise [mailto:parise.tanya@ecrweb.com] Sent: Tuesday, April 20, 2010 9:02 AM To: Antonio Santos Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines Antonio, I appreciate this information. It helps. Do you anticipate responses from any other MECA member companies? Tanya -----Original Message----- From: Antonio Santos [mailto:asantos@meca.org] Sent: Friday, April 09, 2010 5:12 PM To: Tanya Parise Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines Tanya - Here's a response to your questions from one of the MECA member companies (see below). I sent them the questions exactly as you sent them to me. 1. Does MECA have an estimate of the percentage of rich burn engines currently operating with NSCR/three-way catalyst? 2. What would the percentage be for engines below 500 HP? 3. Would the percentage be different if you look at engines at a major source vs. an area source?" Hope this helps. Antonio

---1. For major sources, 100% of rich burn engines would be operating with threeway catalysts. For area sources, the estimate is 60-70% of rich burn engines would be operating with three-way catalysts. These values are across all horsepower ranges and the estimates are based on observations of in-use SI engines. 2. We think the percentage of engines <500 hp equipped with three-way catalysts is about the same as the numbers in 1. above. 3. Yes, see response to 1. above. For some of these engines, the catalyst was retrofitted and, for others, the catalyst came with the original equipment. We don't have a percentage breakdown for OE vs. retrofit catalysts. That said, these engines have very long life-cycles and so the catalyst can be replaced a number of times. As such, we believe a great number of the in-use catalysts are retrofits orreplacements for the original catalyst.

-----Original Message----- From: Tanya Parise [mailto:parise.tanya@ecrweb.com] Sent: Monday, April 05, 2010 1:43 PM To: Antonio Santos Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines Thanks so much. I appreciate you clearing this up. -----Original Message----- From: Antonio Santos [mailto:asantos@meca.org] Sent: Monday, April 05, 2010 11:37 AM To: Tanya Parise Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines That is our old location. MECA's new address is: 2020 North 14th Street, Suite 220, Arlington, VA 22201. Our phone number remains the same: (202) 296-4797. We no longer share a suite with ICAC (they also moved to a new office; their new address is: 1220 N. Fillmore Street, #410, Arlington, VA 22201). ICAC's new phone number is: (703) 812-4811. Antonio

-----Original Message----- From: Tanya Parise [mailto:parise.tanya@ecrweb.com] Sent: Monday, April 05, 2010 11:28 AM To: Antonio Santos Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines No problem. Sounds good. So is your new location the 1730 M Street, NW, Suite 206 address? Or is that your old location? Are you sharing suites with ICAC? I was putting together a contact list of stakeholders and was inputting addresses and phone numbers, etc. Thanks so much. Tanya -----Original Message----- From: Antonio Santos [mailto:asantos@meca.org] Sent: Monday, April 05, 2010 11:19 AM To: Tanya Parise Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines Hi, Tanya. My apologies for not getting back to you sooner. Your e-mail fell through the cracks during our office move last month (we changed e-mail providers as part of the move and messages were lost). Thanks for the reminder. I just sent out an inquiry to the MECA members. As before, I'll send to you whatever I hear back (hopefully I'll have some responses before the end of this week). Antonio

-----Original Message----- From: Tanya Parise [mailto:parise.tanya@ecrweb.com] Sent: Monday, April 05, 2010 9:05 AM To: Antonio Santos Subject: RE: Question Related to EPA's NESHAP for Existing Stationary SI Engines Antonio, Just a friendly follow-up to make sure you received my below information and to find out of MECA has an estimate of the number of engines with three-way catalyst/NSCR? We're on a tight schedule to get the rule finalized, so any feedback you have is appreciated. Tanya -----Original Message----- From: Tanya Parise [mailto:parise.tanya@ecrweb.com] Sent: Sunday, March 14, 2010 12:16 PM To: 'Antonio Santos'Subject: Question Related to EPA's NESHAP for Existing Stationary SI Engines

Antonio, I appreciate all the information MECA has provided so far. I have another question that I'm hoping MECA can help with. Does MECA have an estimate of the percentage of rich burn engines currently operating with NSCR/three-way catalyst? What would the percentage be for engines below 500 HP? Would the percentage be different if you look at engines at a major source vs. an area source? Thanks again for your help. Thanks, Tanya

Tanya Parise EC/R Incorporated 501 Eastowne Drive, Suite 250 Chapel Hill, NC 27514 (919) 484-0417