Memorandum

Subject:		Telephone conversation between Nathan Topham, USEPA and Mark 				DeLaquil, Baker Hostetler

Date:			April 3, 2013

Participants:	 	Nathan Topham, U.S. EPA
			Mark DeLaquil, Baker Hostetler

On April 3, 2013, a telephone conversation took place between Nathan Topham and Mark DeLaquil.  Mr. Topham and Mr. DeLaquil discussed follow-up questions posed by Mr. Topham following a meeting between representatives of US EPA, Baker Hostetler, and East Penn that took place the morning of April 3, 2013. 

The April 3, 2013 meeting is summarized in a separate memorandum included in docket EPA-HQ-OAR-2011-0344. East Penn requested the meeting to present information to US EPA related to East Penn's planned submission of a request for an alternative standard pursuant to CAA section 112(h)(3). 

Mr. Topham asked if providing facilities discretion to choose which wall of a total enclosure to define as the "windward wall" would provide sufficient flexibility to resolve East Penn's uncertainty regarding placement of pressure monitors discussed when the parties met on April 3[rd]. Mr. Topham explained that the choice of windward wall would be added to the mandatory recordkeeping requirements and that this only applies when a totally enclosed area is inside of or a part of a larger structure shielding the enclosed area from the effects of ambient wind. 

Mr. Topham also asked, "If US EPA provided clarification that a 15-minute averaging time for differential pressure monitoring data was intended in the 2012 final rule, would East Penn's concern related to demonstrating negative pressure inside of total enclosures be resolved?". 

Mr. DeLaquil informed Mr. Topham that he would confer with his clients and follow up with US EPA after East Penn had considered EPA's questions.

