United States Environmental Protection Agency, Region 9 

Air Division 

Technical Support Document 

for 

EPA’s Notice of Proposed Rulemaking 

for the 

California State Implementation Plan 

Imperial County Air Pollution Control District’s 

Rule 400.4, Emissions of Oxides of Nitrogen from Wallboard Kilns 

Prepared by: Idalia Pérez 

June 2014 
Imperial County Air Pollution Control District (ICAPCD) 

Submitted Rule 

ICAPCD Rule 400.4, Emissions of Oxides of Nitrogen from Wallboard Kilns 

ß Adopted: October 22, 2013 

ß Submitted: February 10, 2014 

ß Determined complete: April 9, 2014 

Previous Rule Submittals 

There are no outstanding submittals of Rule 400.4. 

SIP-Approved Rule 

There is no SIP-approved version of Rule 400.4. 

Rule Summary 

Rule 400.4 regulates emissions of oxides of nitrogen (NOx) from kilns with a heat input rating of 

MMBtu/hour or larger that operate at wallboard production facilities. 

The emission limits for NOx in the Rule are (Section C): 

ß 30 ppm or 0.036 lb/MMBtu for units fueled with gaseous fuels; 

ß 40 ppm or 0. 052 lb/MMBtu for units fueled with liquid fuels; 

ß Weighted average of the gas and liquid limits when the units are operated with a 

combination of these. 

The rule language has start-up and shutdown exemptions in Section D. During these periods, 

which are capped at two hours and 15 minutes respectively, the emission limit is 60 ppm. 

Testing, recordkeeping and other compliance requirements are contained in various provisions in 

Sections E, F, G and H. 

Effects on Emissions 

According to the rule staff report, there is only one facility in Imperial County that is subject to 

this rule. This facility has low-NOx burners on its kilns since 2009 and already complies with the 

emission limits in the rule. The District does not expect further emission reductions due to the 

implementation of Rule 400.4. 

Rule Evaluation Criteria 

We have primarily used the following three criteria to evaluate Rule 400.4: 

Rule Stringency In ozone nonattainment areas classified as moderate or above, the SIP must 

require Reasonably Available Control Technology (RACT) for each category of sources covered 

by a Control Techniques Guidelines (CTG) document as well as each major source of volatile 

organic compounds (VOCs) or nitrogen oxides (NOx) (see CAA sections 182(b)(2) and (f)). 

The ICAPCD regulates an ozone nonattainment area classified as moderate for the 1997 8-hour 

ozone standards and as marginal for the 2008 8-hour ozone standards (see 40 CFR 81.305). 
Therefore, the CAA section 182(b)(2) RACT requirement for the 1997 8-hour ozone standards 

applies to this area. 

Enforceability CAA section 110(a)(2)(A) requires that regulations submitted to EPA for 

approval into a SIP must be clear and legally enforceable. 

SIP Revisions CAA section 110(l) prohibits EPA from approving any SIP revision that 

would interfere with any applicable requirement concerning attainment and reasonable 

further progress (RFP) or any other applicable requirement of the CAA. In addition, CAA 

section 193 prohibits the modification of any SIP-approved control requirement in effect 

before November 15, 1990 in a nonattainment area without ensuring equivalent or greater 

emissions reductions.

Guidance and policy documents that we used to define specific enforceability and RACT 

requirements include the following: 

ß Issues Relating to VOC Regulation, Cutpoints, Deficiencies, and Deviations (the “Blue 

Book”), US EPA, OAQPS (May 25, 1988). 

ß Guidance Document for Correcting Common VOC and Other Rule Deficiencies, EPA 

Region IX (August 21, 2001, the “Little Bluebook”). 

ß State Implementation Plans; General Preamble for the Implementation of Title I of the 

Clean Air Act Amendments of 1990, 57 FR 13498 (April 16, 1992); 57 FR 18070 (April 

28, 1992). 

ß State Implementation Plans; Nitrogen Oxides Supplement to the General Preamble for 

the Implementation of Title I of the Clean Air Act Amendments of 1990 (the “NOX

Supplement to the General Preamble”), US EPA, 57 FR 55620 (November 25, 1992). 

Evaluation of Rule Stringency 

In the manufacture of wallboard, stucco1is first mixed with various additives and water, then 

spread between two paper sheets that serve as a mold and form a board. The board is dried by 

direct contact with hot combustion gases or by indirect steam heating in a multideck kiln dryer, 

where it is dried by direct contact with hot combustion gases or by indirect steam heating. See

AP42 at page 11.16-3. 

Since no CTG has been issued for this activity, we do not have clear national guidance defining 

presumptive RACT. We searched the RACT/BACT/LAER Clearinghouse 

(http://cfpub.epa.gov/RBLC/) for relevant permit information and looked at other state and local 

SIP rules to determine RACT. We queried the RBLC for permit information using the query 

terms 'kiln' and ‘gypsum’ under the ‘Process Contains’ field. 

Table 1: RBLC Information 

RBLC ID Process Limit 

TX-0480 Gypsum Drying Tunnel Scrubber Stack 0.1500 lb/hour 

VA-0299 Drying Kiln, Wet & Dry Zone Burners 0.1960 lb/MMBtu 

 

1 Stucco is the product of ground gypsum that is heated to remove three-quarters of its chemically bound water. See

AP42 at page 11.16-1. 
VA-0299 Drying Kiln, Wet & Dry Zone End Seal Burners 0.1200 lb/MMBtu 

South Coast AQMD Rule 1147 has emission limits applicable to kilns that were also considered 

in our analysis. 

Table 2: SCAQMD Rule 1147 limits 

Fuel Limit 

Gas < 1200° F: 30 ppm or 0.036 lb/mmBtu 

> 1200° F: 60 ppm or 0.073 lb/mmBtu 

Liquid < 1200° F: 40 ppm or 0.053 lb/mmBtu 

> 1200° F: 60 ppm or 0.080 lb/mmBtu 

Kilns and dryers are usually exempt from state and local prohibitory rules for boilers but these 

sources are similar in that the NOx emissions are combustion byproducts. The limits in Rule 

400.4 are consistent with the limits in ICAPCD Rule 400.2, Boilers, Process Heaters and Steam 

Generators. We believe Rule 400.4 currently implements RACT because the emission limits in 

the rule are within the range of emission limits presented above. 

Evaluation of Enforceability 

Some of the criteria essential in practically enforceable rules include clear statements of 

applicability, specificity of the standard that must be met, explicit statements of compliance time 

frames, explicit statements of the size of exempt units and the length of time of exempt periods, 

and inclusion of record keeping requirements. We believe the submitted rule adequately fulfills 

the relevant criteria identified above and ensure that the rule requirements are adequately 

enforceable. Specifically, the rule: 

· is generally clear and has clear applicability; 

· includes adequate recordkeeping and other compliance provisions; 

· has adequate testing and compliance timeframes. 

Evaluation of SIP Revision Criteria 

The submitted rule is not currently in the SIP, so approval of the requirements would strengthen 

the SIP. Therefore, we propose to determine that an approval of the submittal would comply with 

CAA sections 110(l) and 193 because (1) the proposed SIP revision would not interfere with the 

on-going process for ensuring that requirements for RFP and attainment of the NAAQS are met, 

and (2) the submitted SIP revision is more stringent than the existing SIP requirements. 

Additional Recommendations 

According to AP42 Section 11.16, gypsum processing can be a large source of PM. If this is the 

case for United States Gypsum Company (USG) located in Imperial County, the District should 

evaluate PM controls of this source category. 

Although not currently basis for rule disapproval, EPA recommends that the ICAPCD make the 

following improvement in the next revision of Rule 400.4. 

· If firing on duel fuels, the unit should have a totalizing fuel flow meter and the weighted 

average limit is based on the heat input of each fuel for the duration of the co-firing, not 

on the annual heat input of each fuel. (See Section C.1.c.) 
· The District should include a limit on how long an engine can go without being tested if 

it has not been operated during a calendar year (section G.2.a). 

Recommendation 

EPA staff recommends full approval of ICAPCD submitted Rule 400.4 for incorporation into the 

California Applicable SIP. 

Other References 

1. Submitted Rule 400.4 

2. Staff Report for Rule 400.4 

3. RBLC information 
You are here: EPA Home Air & Radiation TTNWeb - Technology Transfer Network Clean Air Technology Center RACT/BACT/LAER

Clearinghouse RBLC Basic Search RBLC Search Results Pollutant Information 

Pollutant I nform ation 

Click on the Process I nform ation button to see m ore inform ation about the process associated w ith this 

pollutant. 

Or click on the Process List button to return to the list of processes.

FI NAL

RBLC I D: TX-0480

Corporate/ Com pany: JOHNS MANVILLE

Facility Nam e: JOHNS MANVILLE CLEBURNE PLANT

Process: GYPSUM DRYING TUNNEL SCRUBBER STACK

Pollutant: Nitrogen Oxides (NOx) CAS Number: 10102

Pollutant Group(s): InOrganic Compounds, Oxides 

of Nitrogen (NOx),

Particulate Matter (PM),

Substance Registry System: Nitrogen Oxides (NOx)

Pollution Prevention/Add-on Control Equipment/Both/No Controls Feasible: N

P2/Add-on Description:

Test Method: Unspecified 

Percent Efficiency: 0

Compliance Verified: Unknown 

EMISSION LIMITS:

Case-by-Case Basis: BACT-PSD

Other Applicable Requirements:

Other Factors Influence Decision: Unknown 

Emission Limit 1: 0.1500 LB/H

Emission Limit 2: 0.6400 T/YR

Standard Emission Limit: 0

COST DATA:

Cost Verified? No

Dollar Year Used in Cost Estimates:

Cost Effectiveness: 0 $/ton

Incremental Cost Effectiveness: 0 $/ton

Pollutant Notes:

Technology Transfer Network 

Clean Air Technology Center - RACT/BACT/LAER Clearinghouse

http://cfpub.epa.gov/rblc/index.cfm?

action=PermitDetail.PollutantInfo&Facility_ID=26443&Process_ID=105426&Pollutant_ID=1La49s&Pt uer_ pdaCteondtorol n T_Euqeusidapmey, nJut_nIed=1714, 22087814

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Clearinghouse RBLC Basic Search RBLC Search Results Pollutant Information 

Pollutant I nform ation 

Click on the Process I nform ation button to see m ore inform ation about the process associated w ith this 

pollutant. 

Or click on the Process List button to return to the list of processes.

FI NAL

RBLC I D: VA-0299

Corporate/ Com pany: UNITED STATES GYPSUM COMPANY

Facility Nam e: UNITED STATES GYPSUM COMPANY

Process: DRYING KILN, WET & DRY ZONE BURNERS

Pollutant: Nitrogen Oxides (NOx) CAS Number: 10102

Pollutant Group(s): InOrganic Compounds, Oxides 

of Nitrogen (NOx),

Particulate Matter (PM),

Substance Registry System: Nitrogen Oxides (NOx)

Pollution Prevention/Add-on Control Equipment/Both/No Controls Feasible: N

P2/Add-on Description:

Test Method: Unspecified 

Percent Efficiency: 0

Compliance Verified: Unknown 

EMISSION LIMITS:

Case-by-Case Basis: BACT-PSD

Other Applicable Requirements: OPERATING PERMIT 

Other Factors Influence Decision: Unknown 

Emission Limit 1: 19.6000 LB/H

Emission Limit 2: 0 

Standard Emission Limit: 0.1960 LB/MMBTU 

COST DATA:

Cost Verified? No

Dollar Year Used in Cost Estimates:

Cost Effectiveness: 0 $/ton

Incremental Cost Effectiveness: 0 $/ton

Pollutant Notes: EMISSION LIMITS ARE FOR ONE OF TWO BURNERS

Technology Transfer Network 

Clean Air Technology Center - RACT/BACT/LAER Clearinghouse

http://cfpub.epa.gov/rblc/index.cfm?

action=PermitDetail.PollutantInfo&Facility_ID=26487&Process_ID=105021&Pollutant_ID=1La49s&Pt uer_ pdaCteondtorol n T_Euqeusidapmey, nJut_nIed=1714, 12074514

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You are here: EPA Home Air & Radiation TTNWeb - Technology Transfer Network Clean Air Technology Center RACT/BACT/LAER

Clearinghouse RBLC Basic Search RBLC Search Results Pollutant Information 

Pollutant I nform ation 

Click on the Process I nform ation button to see m ore inform ation about the process associated w ith this 

pollutant. 

Or click on the Process List button to return to the list of processes.

FI NAL

RBLC I D: VA-0299

Corporate/ Com pany: UNITED STATES GYPSUM COMPANY

Facility Nam e: UNITED STATES GYPSUM COMPANY

Process: DRYING KILN, WET & DRY ZONE END SEAL BURNERS 

Pollutant: Nitrogen Oxides (NOx) CAS Number: 10102

Pollutant Group(s): InOrganic Compounds, Oxides 

of Nitrogen (NOx),

Particulate Matter (PM),

Substance Registry System: Nitrogen Oxides (NOx)

Pollution Prevention/Add-on Control Equipment/Both/No Controls Feasible: N

P2/Add-on Description:

Test Method: Unspecified 

Percent Efficiency: 0

Compliance Verified: Unknown 

EMISSION LIMITS:

Case-by-Case Basis: BACT-PSD

Other Applicable Requirements: OPERATING PERMIT 

Other Factors Influence Decision: Unknown 

Emission Limit 1: 0.3000 LB/H

Emission Limit 2: 0 

Standard Emission Limit: 0.1200 LB/MMBTU 

COST DATA:

Cost Verified? No

Dollar Year Used in Cost Estimates:

Cost Effectiveness: 0 $/ton

Incremental Cost Effectiveness: 0 $/ton

Pollutant Notes: EMISSIONS ARE FOR ONE OF TWO UNITS

Technology Transfer Network 

Clean Air Technology Center - RACT/BACT/LAER Clearinghouse

http://cfpub.epa.gov/rblc/index.cfm?

action=PermitDetail.PollutantInfo&Facility_ID=26487&Process_ID=105022&Pollutant_ID=1La49s&Pt uer_ pdaCteondtorol n T_Euqeusidapmey, nJut_nIed=1714, 12075114

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