MEMORANDUM TO: Docket EPA-HQ-OAR-2013-0290

FROM: Sharon Nizich, US EPA

SUBJECT: Discussion with Kohler Company

DATE: March 5, 2015

A discussion was held today with Kohler Company to provide clarifications on the proposed Clay 

Ceramics Rule. Discussion items are attached.

Attending:

Research Triangle Institute:

Kristin Sroka

Gabrielle Raymond

Tom Holloway

US EPA:

Sharon Nizich

Keith Barnett

Kohler:

Mike Cassidy, Kohler Wisconsin

Attachment
From: Nizich, Sharon

Sent: Thursday, March 05, 2015 8:46 AM

To: MICHAEL.CASSIDY@kohler.com

Cc: Tom H

Subject: FW: Clarifications for Kohler

Hello Mike – Here are answers to most of your questions.

Sharon Nizich

US EPA

Office of Air Quality Planning and Standards

Sector Policies and Programs Division/SPPD

RTP NC 27711

(919) 541 2825

From: Cassidy Mike [mailto:MICHAEL.CASSIDY@kohler.com]

Sent: Wednesday, March 04, 2015 11:50 AM

To: Nizich, Sharon

Subject: RE: Your phone call

Hi Sharon, tomorrow morning at 9am EST is fine for me for a phone call. My follow-up questions 

are below. 

Mike

· Spray booth emission limits: Does the process throughput during the performance test 

become the defacto throughput limitation going forward? For instance, if a spray booth is 

permitted to apply 250 dry lbs/hr glaze, but due to production considerations, is able to only 

spray 175 lbs/hr during the performance test, is 175 lbs/hr the new spray limit? If so, what if 

emissions measured 40% of the limitation (though throughput was 70% of capacity) in a 

performance test, would the source have any options to spray more glaze than done in the 

performance test considering there’s little indication the limitation could be exceeded?

Response: There is no throughput limit for spray booths in the proposed rule. However, the 

operating limits for spray booths (Table 2 to Subpart KKKKK of Part 63) would be 

established during the initial performance test, so you would have to meet the operating 

limits established at the throughput used during that test. If the operating conditions change 

and the previous conditions are no longer representative (e.g., change in throughput from 

175 to 250 lb/hr), you could always retest to establish new operating limits at the higher 

throughput. However, it is advisable to go ahead and conduct the initial test at the highest 

representative throughput, to avoid additional testing and account for production scenarios 

when higher throughput is needed. Since there is no throughput limit in the proposed rule, 

you could spray more glaze, as long as the operating limits are not exceeded on an 
ongoing basis (as applicable) and the emissions limit is not exceeded during the next 

performance test.

[CASSIDY: Since the MACT rule does not impose a throughput limitation on glaze spray 

operations, if the performance test results on a spray booth show compliance with the Table 

1 emission limits, whether 175 lbs/hr or 250 lbs/hr glaze is sprayed (per example above), 

the booth is considered to be in compliance with the MACT rule and the only on-going 

operating conditions for a source are from Table 2, items 8 and 9, which require routine 

visual inspections of spray booths, but no tracking of glaze use against the quantity of glaze 

sprayed during the performance test. Is this correct? If this is not correct, more information 

is needed, such as must glaze use be tracked for each booth on a 3-hour block average 

basis?] 

Response: Yes, this is correct. You would only need to know the quantity of glaze sprayed 

during the performance test in order to compare emissions to the emission limit (lb/ton of 

glaze sprayed).

· 1F Tunnel kiln emission limits: Does the process throughput during the performance test 

become the defacto throughput limitation going forward? For instance, if a tunnel kiln is 

permitted to process 3 tons greenware/hr, but due to production considerations, only fires 2 

tons/hr during the performance test, is 2 tons/hr the new kiln throughput limit? If so, what if 

emissions measured 40% of the limitation (though throughput was 67% of capacity) in a 

performance test, would the source have any options to spray more glaze than done in the 

performance test considering there’s little indication the limitation could be exceeded? This 

same question applies to kiln process parameters like temperature. Variability is an 

element of performance and source operators need some flexibility for source operation 

when there’s no indication that an emission limit can be exceeded. Vitreous plants are 

highly integrated and totally dependent on the processes up and down the process 

line. You cannot just flip a switch to make a tunnel kiln process more ware for a few days of 

testing, then flip the switch back off. Increasing production requires an increase at every 

process step along the way, and it takes considerable time to effect process rate changes.

Response: There is a throughput operating limit in the proposed rule for uncontrolled tunnel 

kilns (item 5b in Table 2 to Subpart KKKKK of Part 63) that would be established during the 

initial performance test that you would be required to meet on an ongoing basis (e.g., 2 

tons/hr). There are also other operating limits that you would have to meet, which would be 

established at the throughput used during the initial test. If the operating conditions change 

and the previous conditions are no longer representative (e.g., change in throughput from 2 

to 3 tons/hr), you could always retest to establish a new operating limit for throughput and 

new operating limits for the other parameters at the higher throughput. However, it is 

advisable to go ahead and conduct the initial test at the highest representative throughput, 

to avoid additional testing, account for production scenarios when higher throughput is 

needed, and provide a compliance cushion. For controlled tunnel kilns (no throughput 

operating limit), you could increase throughput, as long as the operating limits are not 

exceeded on an ongoing basis (as applicable) and the emissions limit is not exceeded 

during the next performance test. For uncontrolled tunnel kilns (required throughput 

operating limit), you could not exceed that throughput operating limit.

[CASSIDY: It appears the only throughput operating limit that will apply to a kiln is per item 

5b in Table 2. I understand this condition applies to acid gas (HCL-equivalent) compliance 
only, and if performance testing shows the maximum potential HCL-equivalent emissions 

are not capable of exceeding the HCL-equivalent limit in Table 1, then no on-going process 

rate monitoring (ware throughput) is required as no operating limit applies. Is this 

correct? Performance testing for PM, Hg, and D/F is used to assess compliance with the 

Table 1 limits, but no on-going process rate monitoring is required for these HAP; is this 

correct? If not, then please explain what process rate monitoring applies as a different 

process rate will likely be determined for each different HAP emissions test, and it’s unclear 

which process rate would apply for compliance demonstration. Also, if process rate 

monitoring will apply, is it to be based on some 3-hour block average from the performance 

test? If no on-going process rate monitoring or limitations apply, the only other operating 

limit I see in Table 2 is for kiln temperature monitoring, with the minimum limit established 

during the D/F performance test. Is this correct? I find the wording in condition §63.8595 

and in Tables 1 and 2 to be somewhat confusing and my concern is that the performance 

test results will be used to significantly limit kiln and spray booth operational flexibility going 

forward.] 

Response: Yes, this is correct. Process rate monitoring would only apply if your HClequivalent emissions exceed the limit in Table 1. It is not required for any other pollutants or 

if your HCl-equivalent emissions are below the limit in Table 1. You would need to conduct 

process rate monitoring during the performance test if you are planning to comply with a 

lb/ton of fired product emission limit and would need to compare emissions to that limit. The 

only other operating limits for uncontrolled kilns are VE (to demonstrate compliance with 

non-Hg metal standard) and kiln peak temperature (to demonstrate compliance with D/F 

standard). We can discuss specific wording concerns in §63.8595 and Tables 1 and 2 

during the call.

On a new topic, why did EPA not evaluate health-based standards for the other HAP, like 

Hg and D/F? The preamble identifies that 99.3% of all HAP emitted from kilns are acidgases. So very little of any other HAP are emitted and EPA’s background information 

shows that <3 lbs Hg are emitted per kiln per year, and less than 30 mg D/F are emitted per 

kiln per year. These rates are so small, that it seems a health-based compliance option 

would be appropriate, but I don’t see any information on why or whether this was evaluated 

or not.

Response: CAA section 112(d)(4) provides that for HAP with established health thresholds, 

the EPA has the discretionary authority to consider such health thresholds when 

establishing emission standards under CAA section 112(d). HF and HCl were determined to 

be threshold pollutants (79 FR 75639-41). It is unlikely that D/F and Hg would be 

considered threshold pollutants. D/F is a probable human carcinogen, and some forms of 

Hg (e.g., methylmercury) are considered possible human carcinogens (www.epa.gov/iris), 

and EPA presumptively concludes that known, probable and possible carcinogens (Group 

A, B and C pollutants) should not be categorized as threshold pollutants (79 FR 75639).

All of our kilns are uncontrolled. I can envision a scenario where a performance test shows 

emissions might exceed the Hg or D/F limitations in Table 1. I can further envision that the 

technical solution might be for add-on controls to reduce emissions below the Table 1 thresholds, 

so a source would be looking at a control device to remove a mg or 2 of D/F per year, or a fraction 

of a lb of Hg per year. This becomes an outrageously expensive proposition for a source, 

especially when emissions are so small that do not / may not pose a health or environmental 

risk. 
From: Nizich, Sharon [mailto:Nizich.Sharon@epa.gov]

Sent: Wednesday, March 04, 2015 9:29 AM

To: Cassidy Mike

Subject: Your phone call

Hello MikeI got your voice mail and tried to call but you were not at your desk.

Please email me the question so we can be prepared to discuss. Tomorrow is better for me so let 

me know if you are available around 9 am eastern time – thanks.

Sharon Nizich

US EPA

Office of Air Quality Planning and Standards

Sector Policies and Programs Division/SPPD

RTP NC 27711

(919) 541 2825