From: Chuck French [French.Chuck@epamail.epa.gov]

Sent: Tuesday, August 14, 2012 11:41 AM

To: Higgins, Cortney

Cc: Ann Johnson; Hancy, Cindy Wang; Erin Newman; Fred Talcott; Jan Tierney; Kelly Rimer; 

Mark Morris; Phil Mulrine; Marinshaw, Richard; Robin Langdon; Sara Ayres; Steve Fruh; 

Tim Benner; Tom Walton

Subject: RE: EO 13563 Interagency Comments on Chromium RTR

Categories: Red Category

Hi Cortney, 

Regarding the question (shown below) on the Danish study, here is a summary of the 

calculations we did to equate the Danish Study data to US equivalent: 

 

Flow rate during Danish tests: 180 dscm/hr = 106 dscf/min 

Tank surface area: 0.22 m2 = 2.37 ft2 

Actual ventilation rate in Danish study: 106/2.37 = 44.7 CFM/m2 

Recommended minimum ventilation rate in US: 250 CFM/m2 

Adjusted flowrate for Danish Study: 250 x 2.37 = 592 CFM 

Estimated at standard conditions: 592 x 0.96 = 568 dscf/min 

Factor to convert Danish study results to US equivalent: 106/568 = 0.187 

 

Average concentrations reported in Danish study: 

Using PFOS: 0.117 mg/dscm 

Using Non-PFOS: 0.0362 mg/dscm 

 

Adjusted concentrations 

Using PFOS: 0.117 x 0.187 = 0.022 mg/dscm 

Using Non-PFOS: 0.0362 x 0.187 = 0.0067 mg/dscm 

 

The recommended ventilation rate of 250 CFM/ft2 in the U.S. is what is required “to 

maintain minimum control velocities” across the tank surface area. Thus, tanks are 

typically designed for higher ventilation rates, thereby decreasing emissions 

concentration. Therefore, the calculated value of 0.0067 mg/dscm is considered a 

maximum value and actual tanks would have greater flow rate and lower emissions 

concentrations. 

 

Reference for recommended ventilation rate: Industrial Ventilation – A Manual of 

Recommended Practice, American Conference of Governmental Industrial Hygienists. 

 

Let us know if you have questions. 

Thanks. 

Chuck 

Phone: 919-541-7912 

"Higgins, Cortney" ---08/14/2012 09:00:12 AM---Hi Chuck, I received the following question - can we 

talk about this at noon today? I'll let you kn 
From: "Higgins, Cortney" <Cortney_Higgins@omb.eop.gov> 

To: Chuck French/RTP/USEPA/US@EPA 

Date: 08/14/2012 09:00 AM 

Subject: RE: EO 13563 Interagency Comments on Chromium RTR

Hi Chuck, 

I received the following question – can we talk about this at noon today? I’ll let you know by noon if 

there are any 

additional questions. 

It would be useful to get a quick explanation of how EPA compared the Danish surface tension 

levels to what they would be in the USA due to EPA’s reliance on increased air flow (or add on 

control devices used) in the USA. The Danish study does mention that fume suppressants work 

better with less air flow. 

Thanks, 

Cortney 

From: Chuck French [mailto:French.Chuck@epamail.epa.gov] 

Sent: Monday, August 13, 2012 12:36 PM 

To: Higgins, Cortney 

Subject: Re: EO 13563 Interagency Comments on Chromium RTR

Hi Cortney, 

I realize you are out of the office today. I hope you are having a good day. Anyway, please let us know 

ASAP if there are any remaining comments or issues. 

Thanks. 

Chuck 

Phone: 919-541-7912 

"Higgins, Cortney" ---08/10/2012 09:46:29 PM---Yes. Thanks! From: Chuck French 

[mailto:French.Chuck@epamail.epa.gov] 

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

To: Chuck French/RTP/USEPA/US@EPA 

Date: 08/10/2012 09:46 PM 

Subject: Re: EO 13563 Interagency Comments on Chromium RTR

Yes. Thanks! 
From: Chuck French [mailto:French.Chuck@epamail.epa.gov] 

Sent: Friday, August 10, 2012 06:31 PM 

To: Higgins, Cortney 

Subject: Fw: EO 13563 Interagency Comments on Chromium RTR 

Hi Cortney, 

Did you receive the revised preamble/rule? 

Thanks. 

Have a good weekend. 

Chuck 

Phone: 919-541-7912 

----- Forwarded by Chuck French/RTP/USEPA/US on 08/10/2012 06:29 PM -----

From: Chuck French/RTP/USEPA/US 

To: Chuck French/RTP/USEPA/US@EPA 

Cc: "Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>, Ann Johnson/DC/USEPA/US@EPA, 

Mark Morris/RTP/USEPA/US@EPA, Nathan_J._Frey@omb.eop.gov, Phil 

Mulrine/RTP/USEPA/US@EPA, Robin Langdon/RTP/USEPA/US@EPA, Tom 

Walton/RTP/USEPA/US@EPA, chancy@rti.org, Erin Newman/R5/USEPA/US@EPA, Jan 

Tierney/DC/USEPA/US@EPA, Kelly Rimer/RTP/USEPA/US@EPA, rjmarinshaw@rti.org, 

Sara Ayres/DC/USEPA/US@EPA, Steve Fruh/RTP/USEPA/US@EPA, Tim 

Benner/DC/USEPA/US@EPA 

Date: 08/10/2012 06:24 PM 

Subject: Re: EO 13563 Interagency Comments on Chromium RTR 

Hi Cortney, 

We made edits to the preamble/rule to address comments we discussed on 8/8/2012. Attached is a 

revised preamble and rule. One version shows changes in "track changes", the other is a clean version. 

Let me know if you have questions. 

Thanks. 

Chuck French 

Phone: 919-541-7912 

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