ANADARKO		PETROLEUM		CORPORATION			1201 LAKE ROBBINS DRIVE, THE WOODLANDS, TEXAS 77380

			P.O. BOX 1330		HOUSTON, TEXAS 77251‐1330			U.S.A.			PH. (832)636‐1000

February	5,	2014	 						

Mr.	Stanley	Krivo		

U.S.	EPA	Region	4	

61	Forsyth	Street,	S.W.	

Atlanta,	GA	30303‐8960	

RE: Anadarko BlackHawk and BlackHornet OCS Air Permit Application for Drilling,

Exploration, and Maintenance Activities in the Eastern Gulf of Mexico

EPA’s Follow up Comments in Email Dated January 16, 2014

Dear	Mr.	Krivo:	

EPA	Region	4	provided	follow‐up	comments	via	email	on	January	16,	2014	to	the	responses	submitted	

by	Anadarko	Petroleum	Corporation	(Anadarko)	in	November	2013.		This	letter	addresses	the	follow	up	

comments	except	for	the	comment	related	to	air	dispersion	modeling	(i.e.,	a	comment	related	to	validity	

of	the	air	impact	assessment	using	a	single	supply	boat)	Refer	to	EPA’s	incompleteness	letter	for	a	

specific	comment	number	provided	in	this	letter.	

21. Ozone	data	used	in	CALPUFF	modeling	analyses	

The	use	of	ozone	data	representative	of	the	modeling	domain	and/or	the	PSD	Class	I	area	is	

appropriate.		Data	acquired	at	Sumatra,	FL	would	be	appropriate	for	St.	Marks	and	Bradwell	Bay	

Class	I	impact	analyses.		The	appropriateness	for	application	at	the	Breton	PSD	Class	I	area	has	

not	been	addressed.	

Anadarko Response:

	 	

Per	discussions	with	Stanley	Krivo	of	EPA	Region	4,	Mr.	Rahul	Pendse	of	Trinity	Consultants	

contacted	Ms.	Jill	Webster	of	US	Fish	and	Wildlife	Service	[Federal	Land	Manager	for	Breton	

NWR]	on	December	10,	2013	and	obtained	a	confirmation	that	use	of	ambient	ozone	data	from	a	

monitor	in	Sumatra,	FL	(code‐SUM	156)	for	AQRV	analysis	for	Breton	NWR	Class	I	area	is	

acceptable	to	US	Fish	and	Wildlife	Service.			

																																																																																																																																																										

22. Screening	ambient	concentration	levels	for	soils	and	vegetation

The	EPA	referenced	screening	ambient	concentration	levels	were	not	addressed	in	the	

response.		Rather	the	response	reiterated	the	fact	that	the	provided	qualitative	conclusion	was	
Mr.	Krivo	

Page	2	of	4	 	 	

based	on	the	Secondary	NAAQS.		Comparison	of	the	screening	levels	in	“A	Screening	Procedure	

for	Impacts	of	Air	Pollution	Sources	on	Plants,	Soils,	and	Animals”	were	not	provided.	

Anadarko Response:

Comparison	of	screening	levels	for	pollutants	for	which	air	dispersion	modeling	was	performed	

(i.e.,	CO	and	NO2)	is	presented	in	Table	1	below.		Per	procedures	described	in	Section	5.1	of	“A

Screening Procedure for Impacts of Air Pollution Sources on Plants, Soils, and Animals”	(EPA	

Guidance	Document),	the	background	concentration	was	added	to	the	modeled	concentrations.		

The	background	concentration	data	was	obtained	from	the	monitoring	station	located	at	

Houma,	Louisiana.		The	monitoring	station	located	at	Houma,	Louisiana	was	considered	as	a	

representative	monitoring	station	based	on	its	proximity	to	the	project	location	as	well	as	the	

Gulf	of	Mexico	shoreline.		The	most	recent	meteorological	data	for	three	calendar	years	(2010	to	

2012)	were	considered	for	obtaining	a	background	concentration.

As	shown	in	Table	1,	total	(modeled	concentration	+	background)	1‐hour	concentration	for	CO	is	

less	than	the	EPA	screening	concentration	for	1‐week.		Since	the	total	concentration	of	CO	for	1‐

hour	averaging	period	would	be	equal	or	higher	than	the	concentration	of	CO	for	1‐week	

averaging	period,	the	screening	concentration	of	CO	for	1‐week	averaging	period	was	compared	

against	the	total	concentration	of	CO	for	1‐hour	averaging	period	as	a	conservative	approach.		

The	same	logic	was	applied	for	comparison	of	total	1‐hour	concentration	of	NOx	against	4‐hour	

and	8‐hour	screening	concentrations	of	NOx.			

Table 1	‐	Comparison of Screening Levels for Modeled Criteria Pollutants

Pollutant Averaging

Period

Air

Dispersion

Analysis

Results	‐	

Class II

Receptors

Background

Concentration

[1]

Total EPA Screening

Concentrations

[2]

Total > EPA

Screening?

(μg/m3) (μg/m3) (μg/m3) (μg/m3)	 		

CO

1	hour	 13.66	 3561	 3575	 ‐‐	 ‐‐	

1	week	 ‐‐		 	‐‐	 ‐‐		 1,800,000	 No	

NO2

1	hour	 5.04	 119	 124	 ‐‐	 ‐‐	

4	hours	 ‐‐		 	‐‐	 ‐‐		 3,760	 No	

8	hours	 ‐‐		 ‐‐		 ‐‐		 3,760	 No	

1	year	 0.09	 49	 50	 94‐188	 No	

[1]	To	represent	the	most	conservative	scenario,	the	background	hourly	concentrations	were	obtained	by	

choosing	the	maximum	of	the	daily	maximum	concentrations	for	three	calendar	years.		The	background	annual	

concentrations	were	obtained	by	choosing	the	average	of	daily	max	concentrations	for	three	calendar	years	at	

Houma,	LA	monitoring	station.	

[2]	Screening	concentrations	set	in	Table	3.1 of	the	EPA	Guidance	Document.

As	described	in	Section	5.2.2	of	the	EPA	guidance	document,	the	source’s	potential	to	emit	in	

tons	per	year	could	directly	be	compared	with	the	significant	emission	rates	listed	in	Table	5.6	

and	Table	5.7	of	the	EPA	Guidance	Document	for	pollutants	that	were	not	modeled	using	an	air	

dispersion	modeling	program.		Table	2	and	Table	3	provide	a	list	of	pollutants	for	which	the	air	
Mr.	Krivo	

Page	3	of	4	 	 	

dispersion	modeling	was	not	required	for	the	proposed	project.		Table	2	and	Table	3	also	

provide	a	comparison	of	potential	emissions	of	these	pollutants	and	corresponding	Screening	

Thresholds	specified	in	the	EPA	guidance	document.			

Table 2	‐	Comparison of Significant Emission Rates for Direct Acting Pollutants.

Pollutant Averaging

Period

Significant

Emission Rate

(SER)

Proposed

Emission Rate Proposed

Emission Rate

> SER?

(T/year) (T/year)

SO2

1	hour	 160	

1.02	

No	

3	hours	 170	 No	

Annual	 171	 No	

Pb 3	months	 11	 0.02	 No	

Beryllium 1	month	 0.057	 <0.001	 No	

As	shown	in	Table	2,	proposed	emission	rates	for	all	pollutants	are	less	than	their	respective	

SERs.		As	described	in	Section	5.2.2	of	the	EPA	Guidance	Document,	the	proposed	emission	rates	

of	the	trace	elements	were	adjusted	to	reflect	expected	life	of	the	project	(i.e.,	five	years.)		Since	

Anadarko’s	lease	for	the	BlackHawk	and	BlackHornet	drillships	will	be	expiring	in	five	years,	the	

life	of	the	project	is	considered	as	five	years.		

Table 3	‐	Comparison of Significant Emission Rates for Trace Elements

Pollutant [1]

EPA Screening

Concentrations

(for 10 years

source life) [2]

EPA Screening

Concentrations

(for 5 years

source life) [3]

Project

Emission

Rate

Emission

Rate > SER?

(T/year) (T/year) (T/year)

Arsenic 0.4	 0.8	 <0.001	 No	

Cadmium 0.037	 0.074	 <0.001	 No	

Chromium 1.1	 2.2	 <0.001	 No	

Cobalt 1.2	 2.4	 <0.001	 No	

Lead 24	 48	 0.017	 No	

Manganese 0.33	 0.66	 <0.001	 No	

Mercury 61	 122	 <0.001	 No	

Nickel 67	 134	 <0.001	 No	

Selenium 0.67	 1.34	 <0.001	 No	

[1]	Includes	only	those	pollutants	which	are	expected	to	be	emitted	during	the	project.	

[2]	The	smallest	value	among	the	significant	emission	rates	criteria	for	soils,	plant	tissues,	

and	animals	from	Table	5.7	of	the	EPA	Guidance	Document.	

[3]	The	significant	emission	rates	are	converted	based	on	a	source	lifetime	of	five	years.	
Mr.	Krivo	

Page	4	of	4	 	 	

As	shown	in	Table	3,	proposed	emission	rates	for	all	pollutants	are	less	than	their	respective	

SERs.		Hence,	no	further	analysis	is	required.	

24. Confirm	the	Breeze	software	used	the	unmodified	versions	of	the	regulatory	CALPUFF	modeling	

system.	

The	response	indicates	the	approved	versions	of	the	CALPUFF	modeling	system	were	

used.		Confirmation	is	needed	that	the	BREEZE	modeling	system	uses	for	this	analysis	

incorporates	the	unmodified	regulatory	versions	of	CALMET,	CALPUFF,	and	CALPOST.	

		

Anadarko Response:

Trinity	confirms	that	the	BREEZE	software	used	the	following	unmodified	regulatory	versions	

of	the	CALPUFF	Modeling	System	for	the	submitted	air	dispersion	modeling	analysis:		

 CALPUFF	version	5.8,	level	070623	

 CALMET	version	5.8,	level	070623	

 CALPOST	version	6.221,	level	080724	

Please	do	not	hesitate	to	contact	Mr.	Rahul	Pendse,	Trinity	Consultants	at	(225)	346‐4003	or	Ms.	Sara	

Carlson,	Anadarko	at	(832)	636‐1273	if	you	have	any	questions	or	require	additional	information.