Page 1 of 10

**Subpart Z —** **Phosphoric Acid Production** § 98.260 Definition of the source category. The phosphoric acid production source category consists of facilities with a wet
-process phosphoric acid process line used to produce phosphoric acid. A wet
-process phosphoric acid process line is the production unit or units identified by an individual identification number in an operating permit and/or any process unit or group of process units at a facili ty reacting phosphate rock from a common supply source with acid. § 98.261 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a phosphoric acid production process and the facility meets the requirements of eithe r §98.2(a)(1) or (a)(2). § 98.262 GHGs to report. (a) You must report CO 2 process emissions from each wet
process phosphoric acid process line. (b) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of CO 2 , CH 4 , and N 2 O from each stationary combustion unit following the requirements of subpart C of this part. § 98.263 Calculating GHG emissions. You must calculate and report the annual process CO 2 emission s from each wet -process phosphoric acid process lin ePage 2 of 10

using the procedures in either paragraph (a) or (b) of this section. (a) Calculate and report under this subpart the process CO 2 emission s by operating and maintaining a CEMS according to the Tier 4 Calculation Methodology specified in §98.33(a)(4) and a ll associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources). (b) Calculate and report under this subpart the process CO 2 emission s using the procedures in paragraphs (b)(1) and (b)(2) of this section. (1) Ca lculate the annual CO 2 mass emissions from each wet
process phosphoric acid process line using the methods in paragraphs (b)(1)(i) or (ii) of this section, as applicable. (i) If your process measurement provides the inorganic carbon content of phosphate ro ck as an output, calculate and report the process CO 2 emission s from each wet -process phosphoric acid process line using Equation Z

– 1a of this section:

Where:
E m = Annual CO 2 mass emissions from a wet
-process phosphoric acid process line m according to this Equation Z

– 1a (metric tons). IC n,i = Inorganic carbon content of a grab sample batch of phosphate rock by origin i obtained during month n, from the carbon analysisPage 3 of 10 results (percent by weight, expressed as a decimal fraction). P n,i = Mass of phosphate rock by origin i consumed in month n by wet -process phosphoric acid process line m (tons). z = Number of months during which the process line m operates. b = Number of different types of phosphate rock in month, by origin. If the grab sample is a composite sample of rock from more than one origin, b = 1. 2000/2205 = Conversion factor to convert tons to metric tons. 44/12 = Ratio of molecular weights, CO 2 to carbon. (ii) If your p rocess measurement provides the CO 2 content directly as an output, calculate and report the process CO 2 emission s from each wet -process phosphoric acid process line using Equation Z

– 1b of this section:

Where:
E m = Annual CO 2 mass emissions from a wet
-process phosphoric acid process line m according to this Equation Z

– 1b (metric tons). CO 2 n,i = Carbon dioxide content of a grab sample batch of phosphate rock by origin i obtained during month n (percent by weight, expressed as a decimal fraction). P n,i = Mass of phosphate rock by origin i consumed in month n by wet -process phosphoric acid process line m (tons). z = Number of months during which the process line m operates.Page 4 of 10

b = Number of different types of phosphate rock in month, by origin. If the grab sample is a composite sample of rock from more than one origin, b=1. 2000/2205 = Conversion factor to convert tons to metric tons. (2) You must determine the total emissions from the facility using Equation Z

– 2 of this section:

Where: CO 2 = Annual process CO 2 emission s from phosphoric acid production facility (metric tons/year). E m = Annual process CO 2 emission s from wet -process phosphoric acid process line m (metric tons/year). p = Number of wet -process phosphoric acid process lines. (c) If GHG emissions from a wet
-process phosphoric acid process line are vented through the same stack as any combustion unit or process equipment that reports CO 2 emission s using a CEMS that complies with the Tier 4 Calculation Methodology in subpart C of this part (General Stationary Fuel Combustion Sources), then the calculation methodology in paragraph (b) of this section shall not be used to calculate process emissions. The owner or operator shall report under this subpart the combined
s tack emissions according to the Tier 4 Calculation Methodology in §98.33(a)(4) and all associated requirements for Tier 4 in subpart C of this part.Page 5 of 10

§ 98.264 Monitoring and QA/QC requirements. (a) You must obtain a monthly grab sample of phosphate rock dir ectly from the rock being fed to the process line before it enters the mill using one of the following methods. You may conduct the representative bulk sampling using a method published by a consensus standards organization, or you may use industry consens us standard practice methods, including but not limited to the Phosphate Mining States Methods Used and Adopted by the Association of Fertilizer and Phosphate Chemists (AFPC ). If phosphate rock is obtained from more than one origin in a month, you must obtain a sample from each origin of rock or obtain a composite representative sample. (b) You must determine the carbon dioxide or inorganic carbon content of each monthly grab sample of phosphate rock (consumed in the production of phosphoric acid). You may use a method published by a consensus standards organization, or you may use industry consensus standard practice methods, including but not limited to the Phosphate Mining States Methods Used and Adopted by AFPC . (c) You must determine the mass of phosphate rock consumed each month (by origin) in each wet
-process phosphoric acid process line. You can use existing plant procedures that are used for accounting purposes (such as sales records) or you can use data from existing monitoring equipment that is used toPage 6 of 10

measure total mass flow of phosphorous -bearing feed under 40 CFR part 60 or part 63. § 98.265 Procedures for estimating missing data. A complete record of all measured parameters used in the GHG emissions calculations is required. Therefore, whenever a quality
- assured value of a required parameter is unavailable, a substitute data value for the missing parameter must be used in the calcu lations as specified in paragraphs (a) and (b) of this section. (a) For each missing value of the inorganic carbon content or CO 2 content of phosphate rock (by origin), you must use the appropriate default factor provided in Table Z

– 1 o f this subpart. Alternatively, you must determine a substitute data value by calculating the arithmetic average of the quality
assured values of inorganic carbon contents or CO 2 contents of phosphate rock of origin i ( see Equation Z

– 1 a or Z - 1b of this subpart) from samples immediately preceding and immediately following the missing data incident. If no quality
- assured data on inorganic carbon contents or CO 2 contents of phosphate rock of origin i are available prior to the missing data incident , the substitute data value shall be the first quality
- assured value for inorganic carbon contents or CO 2 contents for phosphate rock of origin i obtained after the missing data period.Page 7 of 10

(b) For each missing value of monthly mass consumption of phosphate ro ck (by origin), you must use the best available estimate based on all available process data or data used for accounting purposes. § 98.266 Data reporting requirements. In addition to the information required by §98.3(c), each annual report must contain the information specified in paragraphs (a) through (f) of this section. (a) Annual phosphoric acid production , by origin of the phosphate rock (tons). (b) Annual phosphoric acid production capacity (tons). (c) Annual arithmetic average percent inorganic carbon or carbon dioxide in phosphate rock from monthly records (percent by weight, expressed as a decimal fraction). (d) Annual phosphate rock consumption from monthly measurement records by origin (tons). (e) If you use a CEMS to measure CO 2 emission s, then you must report the information in paragraphs (e)(1) and (e)(2) of this section. (1) The identification number of each wet
-process phosphoric acid process line. ( 2) The annual CO 2 emission s from each wet -process phosphoric acid process line (metric tons) and the relevantPage 8 of 10

information required under 40 CFR 98.36 (e)(2)(vi) for the Tier 4 Calculation Methodology. (f) If you do not use a CEMS to measure emissions, then you must report the information in paragraphs (f)(1) through (9) of this section. (1) Identification number of each wet
-process phosphoric acid process line. (2) Annual CO 2 emission s from each wet -process phosphoric acid process line (metric tons) as calculated by either Equation Z
– 1a or Equation Z

– 1b of this subpart. (3) Annual phosphoric acid permitted production capacity (tons) for each wet -process phosphoric acid process line (metric tons). (4) Method used to estimate any missing values of inorganic
ca rbon content or carbon dioxide content of phosphate rock for each wet -process phosphoric acid process line. (5) Monthly inorganic carbon content of phosphate rock for each wet -process phosphoric acid process line for which Equation Z
– 1a is used (percent by weight, expressed as a decimal fraction), or CO 2 content (percent by weight, expressed as a decimal fraction) for which Equation Z

– 1b is used. (6) Monthly mass of phosphate rock consumed , by origin, in production for each wet
-process phosphoric acid process line (tons).Page 9 of 10

(7) Number of wet -process phosphoric acid process lines. (8) Number of times missing data procedures were used to estimate phosphate rock consumption (months ), inorganic carbon
c ontents of the phosphate rock (months), and CO 2 contents of the phosphate rock (months). (9) Annual process CO 2 emission s from phosphoric acid production facility (metric tons). § 98.267 Records that must be retained. In addition to the records required by §98.3(g), you must retain the records specified in paragraphs (a) through (c) of this section for each wet
-process phosphoric acid production facility. (a) Monthly mass of phosphate rock consumed by origin ( t ons). (b) Records of all phosphate rock purchases and/or deliveries (if vertically integrated with a mine). (c) Documentation of the procedures used to ensure the accuracy of monthly phosphate rock consumption by origin . § 98.268 Definitions. All terms used in this subpart have the same meaning given in the Clean Air Act and subpart A of this part. **Table Z –**  **1 to Subpart Z of Part 98 —**  **Default Chemical Composition of Phosphate Rock by Origin** 

**Origin Total carbon**  **(per cent by weight)** Page 10 of 10

Central Florida 1.6 North Florida 1.76 North Carolina (Calcined) 0.76 Idaho (Calcined) 0.60 Morocco 1.56