May 5, 2015

Ms. Tina Ndoh

U.S. Environmental Protection Agency

109 T.W. Alexander Drive

Mail Code: D243-04

Research Triangle Park, NC 27709

RE: Summary of Potential Costs for Implementing Phosphate NESHAPs/Recommendations 

for Phosphogypsum Stack Work Practices

Dear Ms. Ndoh:

On behalf of The Fertilizer Institute (“TFI”), this letter follows up on our March 12, 2015

meeting with U.S. Environmental Protection Agency (“EPA” or “Agency”) staff to discuss TFI 

perspectives on the proposed “risk and technology review” (“RTR”) of the existing Phosphoric 

Acid (40 C.F.R. Part 63, Subpart AA) and Phosphate Fertilizer (40 C.F.R. Part 63, Subpart BB), 

National Emission Standards for Hazardous Air Pollutants (“NESHAPs”), which were published in 

the Federal Register on November 7, 2014 (79 Fed. Reg. 66515). 

This letter addresses two topics that were part of the meeting discussion, specifically, 

additional thoughts on the work practices for phosphogypsum stacks and the potential capital 

and operating costs associated with implementing the NESHAPs as proposed.

A. Work Practices for Phophogypsum Stacks

These practices were the subject of an extended discussion during the recent meeting. 

Since then, TFI members have further reflected on the practices as proposed and have 

compiled the following recommendations for modifying those practices proposed by the

Agency and suggesting some additional alternative practices. 

Reword section 63.602(f)(2)(ii) as follows:

(ii) Minimize the surface area of the active gypsum dewatering stack by using a rim 

ditch (cell) building technique or other building technique. Utilize a rim ditch (cell)

building technique or other similar technique thereby reducing the area available for

ponded surfaces on active gypsum dewatering stacks.

Capital View 202.515-2704 office

425 Third Street, S.W., Suite 950 202.270-0094 cell

Washington, DC 20024 aohare@tfi.org
Ms. Tina Dhoh

Page 2

Include a new definition for “rim ditch” (below) addressing the ditch building 

technique that includes compartment initiation and terminal closure phases where a 

ditch doesn’t exist.

Include new definition for Rim Ditch in Section 63.601, as follows:

Rim Ditch – a gypsum dewatering stack construction technique that utilizes 

inner and outer dikes to direct gypsum slurry flow around the perimeter of the stack

before directing the flow and allowing settling of finer materials into the settling 

compartment. For the purpose of this definition, the rim ditch construction technique

include the compartment start-up phase when gypsum is deposited directly into the

settling compartment in preparation for ditch construction as well as the step-in or

terminal phases when most solids must be directed to the settling compartment prior 

to stack closure. Decant return ditches are not rim ditches.

Note: The intent of this definition is to clarify that during the initial and 

terminal phases of rim ditch operation, an actual ditch will not be present. These 

phases are critical components of the construction and de-construction of the rim 

ditch. 

Reword section 63.602(f)(2)(v) reword as follows:

(v) Apply soil caps and vegetation to all side slopes of the active gypsum dewatering 

stack up to 50 feet below the stack top. Prepare and implement a gypsum dewatering 

stack construction and operation plans that includes a geotechnical stability analysis 

to establish elevations at which step-in benches are to be constructed and to include

locations and schedules for drain installations and appropriate cover on the side

slopes below the top of the stack. The plans will be updated at least once every five

years.

Add new alternative work practices under section 63.602(f)(2)(vii)-(ix) as follows:

(vii) Operate the cooling pond systems to adjust the active cooling surface area to 

address weather conditions, seasonal cooling needs and associated production 

changes. Cooling circuit adjustments may be accomplished through utilization of 

either fixed or floating flow diversion devices or by changing flows such that some of 

the heated water is diverted away from portions of the ponded area.

(viii) Provide inputs to the gypsum dewatering stack system to react with and 

precipitate fluoride compounds to insoluble forms.

(ix) Prepare and implement a plan for the dredging of cooling ponds based on 

site-specific conditions. 
Ms. Tina Dhoh

Page 3

(x) A work practice, not otherwise specified above, approved by the 

Administrator (or the State with an approved permit program) on a sitespecific basis.

B. Summary of the Potential Capital and Operating Costs for Implementation

Costs to comply with the proposed rule were another topic of discussion at the March 

meeting between TFI, our members, and EPA. TFI has solicited updated cost estimates from its 

members, and aggregated estimated costs from comments its members submitted to the 

agency. These cost estimates represent a combination of capital costs and a single year of 

operation and maintenance costs and are broken out broadly by cost type category. 

TFI estimates that it would cost between $40 million and $43 million to comply with the 

Agency’s expanded definition of “process line” and additional covered emission sources, 

including clarifiers, defluorination units, and oxidation reactors. These costs include routing 

previously uncovered emissions to scrubbers, installing new scrubbers, and associated 

monitoring. Further, these costs are for capital expenditures and a single year of operation and 

maintenance, they do not include future operation costs. 

TFI estimated in our comments that it would cost our members over $3 million to 

comply with EPA’s proposed switch from a total fluoride surrogate to a hydrogen fluoride 

standard and associated switch to Method 320 from Method 13b. Two TFI members submitted 

revised compliance testing cost estimates to TFI, these cost estimates total $1.75 million to 

comply with FTIR and/or M320 testing. TFI believes, given these estimates that our members 

will quickly exceed $3 million in complying with the M320 requirement. 

EPA has proposed a variety of work practices which the agency believes would reduce 

HF emissions from gypsum stacks. While there is a wide range of costs associated with these 

work practices, TFI members estimate that it could cost close to $500 million to comply with 

the most onerous work practices. Full stack closure to comply with the 80 acre operating limit 

would cost two TFI member facilities at least $150 million alone. 

TFI members also submitted cost estimates for meeting mercury emission limits for 

calciners and cooling system effluent management standards in their comments. The TFI 

member who addressed mercury emission limits, has received estimates from environmental 

engineering firms indicating that compliance with the proposed requirements would cost 

between $26.8 million and $41.1 million. To comply with the cooling system effluent 

management requirements, TFI members estimate that it would cost between $50 million and 

$60 million for capital costs and only one year of operation and maintenance costs of the new 

system. 
Ms. Tina Dhoh

Page 4

In sum, TFI believes that the rule as proposed will cost TFI members between $118 

million to $632 million in capital costs, which could be spread over the first few years, and 

annual operating costs, of which only one year has been included in the estimates. Clearly, this 

is an economically significant rule and deserves consideration by the Office of Management and 

Budget. 

C. Conclusion

Thank you for the opportunity to share this additional information with you regarding 

these important aspects of the NESHAP proposals. Please do not hesitate to contact me at 

(202) 515-2704 or aohare@tfi.org or Wade Foster at (202) 515-2701 with any questions 

regarding the perspectives of TFI on these matters. 

Sincerely, 

Andrew T. O’Hare

Vice President, Public Policy

Cc: Howard Shelanski, Administrator, White House Office of Information and Regulatory 

Affairs

Peter Tsirigotis, EPA Office of Air Quality Planning and Standards

Keith Barnett, EPA Office of Air Quality Planning and Standards