Preliminary Response to the Cold End Memorandum

Portland Cement Association (PCA) provides this preliminary response to the 

information contained in the attached memorandum from Keith Barnett dated March 21, 2011 

(the “Cold End Memorandum”) and supporting documents (attached hereto). PCA greatly 

appreciates EPA’s continuing efforts to address PCA’s concern that cement kilns will 

inappropriately be regulated under the rules for Commercial/Industrial Solid Waste Incinerators 

(“CISWI”) facilities, rather than the Portland Cement National Emissions Standard for 

Hazardous Air Pollutants (“NESHAP”), based on the use of certain alternative ingredients and 

fuels by kilns that may be deemed solid wastes under the Identification of Non-Hazardous 

Secondary Materials that are Solid Wastes rule (40 C.F.R. Part 241). While the interpretation of 

Section 129(g) of the Clean Air Act (“CAA”) articulated in the Cold End Memorandum 

represents a step in the right direction, the memorandum does not resolve our concerns. Nor do 

we agree that the overlap between the Portland Cement NESHAP and the CISWI rule is limited 

to just 18 kilns (the number is significantly higher) or that the revised MACT floor calculations 

are appropriate. In sum:

 Ingredients that may be determined to be solid wastes under Part 241 should not subject 

cement kilns to regulation under CAA Section 129(g) because they are not combusted. 

Therefore, the distinction between the “cold” end of the kiln and other locations is not 

legally relevant to whether ingredients should be regulated under Section 129(g). 

Furthermore, the supposition that ingredients are added only to the “cold” end does not 

accurately capture the full range of practices in the industry. Fundamentally, the location 

at which the ingredients are added to a kiln should not determine whether a kiln is 

classified as a CISWI source because ingredients are not combusted no matter where they 

enter the kiln. 

 Further, the incorrect assumption in the Cold End Memorandum that all ingredients are 

added to the “cold” end of kilns leads EPA to the incorrect conclusion that only 18 kilns 

will be categorized as CISWI kilns based on their use of ingredients. PCA estimates that 

more than 90% of all kilns that are potentially subject to CISWI use ingredients that may 

be determined to be solid wastes under Part 241 and roughly 25% of those kilns introduce 

ingredients in locations other than the apparent “cold” end. In addition, the calculations 

in the memorandum fail to capture all kilns that would appear to be CISWI kilns because 

of EPA’s interpretation of their use of alternative fuels that may be classified as solid 

wastes under Part 241. PCA estimates that approximately 80% percent of all kilns that 

are potentially subject to CISWI use alternative fuels that may be classified as solid waste 

under Part 241. 

 Finally, while PCA appreciates that the Cold End Memorandum represents a helpful 

move toward more rational analysis of alternative ingredients in kilns, the memorandum 

alone is a procedurally deficient means of resolving the underlying issue. The 

memorandum is not an appropriate or reliable tool to amend the contradictory or 

ambiguous language included in the NESHAP, CISWI, and solid waste definition rules, 

preambles, and response to comment documents. Furthermore, memoranda are always 

subject to change without process.
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The Cold End Memorandum and the accompanying materials thus leave the 

“ingredients” and the NESHAP/CISWI overlap issues unresolved. Even with the memorandum, 

EPA has still failed to determine correctly the number of facilities that would be CISWI rather 

than NESHAP sources based on their usage of either alternative ingredients or alternative fuels 

that may be determined to be solid wastes under Part 241. Thus, EPA cannot, at this point, 

calculate what the NESHAP limits should have been. And even if EPA could complete those 

calculations, the Agency would need to go through notice and comment rulemaking to issue 

those emission limits. The Cold End Memorandum therefore serves only to provide further 

evidence that the Portland Cement NESHAP should be reconsidered, stayed, and synchronized 

with reconsideration of the CISWI and solid waste definition rules.

1. The Cold End Memorandum does not resolve the ingredient issues raised by PCA

A. The interpretation of Section 129(g) is inconsistent with the language of the 

Clean Air Act, as ingredients utilized in cement kilns are not “combusted”

Fundamentally, ingredients utilized in cement kilns (whether virgin feedstock or obtained 

from alternative sources) are not “combusted.” The location at which an ingredient enters the 

kiln does not change this key fact. As Section 129(g) provides that Section 129 standards apply 

only to units that “combust” certain types of materials, Section 129 standards cannot apply to 

units that use those materials as ingredients. 

As discussed at length in PCA’s comments on the proposed CISWI and solid waste 

definition rules, under the plain meaning of the word “combust,” materials that are used as 

ingredients in an industrial process are not “combusted.” Common dictionary definitions make 

clear that a unit “combusts” fuels but not ingredients. The feedstock for clinker that is placed 

into the kiln is incorporated into the clinker product, not “combusted.” Thus, any secondary 

materials that may be used as substitutes for mined or virgin feedstock become incorporated into 

the clinker product and are not “combusted.” Much like cooking, it should not matter when and 

where the ingredients are added: whether they are mixed together before being added to the pan, 

added directly to the pan, or added in after cooking, they are still ingredients and are not 

combusted.

EPA accordingly has no authority under the plain terms of Section 129 to regulate 

portland cement kilns’ use of secondary materials as ingredients. This conclusion is supported 

by the fact that there is nothing in the legislative history of Section 129 that indicates any focus 

whatsoever on the use of ingredients. For this reason, the Cold End Memorandum’s distinction

between materials added to the “cold” and “hot” ends of kilns as a rule of thumb is not legally 

relevant.1 Ingredients (whether virgin or alternative) should not trigger the applicability of the 

CISWI rules for cement kilns regardless of where they are introduced into the process.

 

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Furthermore, as discussed below, it is not clear what is meant by the “hot” and “cold” ends at kilns that have preheaters or precalciners, especially given that precalciner kilns have a second heat source.
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B. The assumption that ingredients are only introduced into kilns via the “cold” 

end is incorrect

The Cold End Memorandum’s conclusion that there are only 18 remaining CISWI kilns 

is based on the fundamental assumption that no kilns will be classified as CISWI sources based 

on the use of ingredients. While, as discussed above, a correct reading of Section 129(g) leads to 

that assumption, the Cold End Memorandum uses a different, and incorrect, rationale. The 

memorandum apparently assumes that all ingredients are added to kilns from the “cold” end, an 

assumption that is factually wrong. 

While many ingredients are added to the “cold” end of the kiln, that is not true for all 

ingredients or all kilns. Ingredients are added to kilns in a variety of ways and locations not 

envisioned by the Cold End Memorandum. For example, it does not appear that the Cold End 

Memorandum would exclude ingredients added in places other than the “cold” end from 

coverage under the CISWI rule, as illustrated in the following examples:

 Ingredients recycled during the process. Two types of materials are removed from the 

kiln exhaust gases, typically by the air pollution control devices, and returned to the 

process as ingredients. The first is incompletely calcined material that is recycled back 

into the kiln as a normal part of the clinker manufacturing process. The second is other 

fine-grained, solid material removed from the system to allow the clinker to meet specific 

quality standards or to maintain process stabilization.2 

Both of these materials may be reintroduced to the kilns in various places, depending on 

the kiln design and process. In wet process kilns, these ingredients are typically added 

near the kiln flame through insufflation or at mid-kiln via dust scoops.3 In long-dry 

kilns, they are most often transferred to a feed bin and added to the raw meal feed just 

prior to the cold end of the kiln. In preheater and preheater/precalciner kilns, they are 

typically transferred to a feed bin and added to the raw meal feed just prior to the 

preheater tower.

To be clear, neither material is discarded, much less combusted, and therefore it would be 

inappropriate to include them within the scope of Part 241 or use them to trigger the 

applicability of CAA Section 129.

 Kilns with preheaters/precalciners. It is unclear how the Cold End Memorandum would 

apply to preheater and precalciner kilns, as they heat ingredients in more than one 

location, including away from the kiln flame “hot” end. Preheater kilns have preheater 

towers that use the heat produced by the kiln to preheat the ingredients as they move 

through the various stages of the tower. In addition, ingredients can be added part way 

 

2 EPA has previously referred to these types of materials as “cement kiln dust” or “CKD,” although it has never 

promulgated a regulatory definition of that term. We do not use that term in this memorandum because it is most 

appropriately used to describe material that is removed entirely from the process and sold or disposed of.

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It is unclear under the Cold End Memorandum whether ingredients added mid-kiln would be considered to have 

been added to the “cold” or “hot” end.
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through the process, but still before the kiln. Moreover, precalciner kilns have a second 

heat source to precalcine limestone and heat other ingredients prior to their introduction 

into the rotary kiln. Thus, from the brief discussion in the Cold End Memorandum, it is 

unclear what EPA would consider to be the “cold” or “hot” end of such a kiln. 

Thus, even if the position articulated in the Cold End Memorandum were deemed a 

legally effective rule (which it cannot be as explained below), a substantial number of kilns 

would still be CISWI kilns because they utilize alternative ingredients that are not fed to the 

“cold” end of the kiln. 

Rather than suggesting a distinction that does not match actual practices in the industry, 

EPA should make clear that ingredients do not trigger the CISWI rules because they are not

combusted, regardless of where they are introduced into the process and regardless of whether 

they would otherwise qualify as solid waste. The ingredients issue cannot be substantively 

resolved until this point is stated clearly and directly (for example, as explained below, in a final 

rule issued after notice and an opportunity for comment), rather than as a rule of thumb regarding 

the location at which the ingredients are added to the kiln. Furthermore, even if the 

interpretation in the Cold End Memorandum did account for all potential ingredient uses, which 

it does not, EPA should still not adopt it here. The search for more efficient means of 

manufacturing portland cement is ongoing. Techniques may be developed in the future that 

would increase efficiency through alternative methods of adding ingredients. EPA should not 

stifle innovation by interpreting Section 129(g) to mean that such new techniques may trigger 

applicability of the CISWI rule.

C. The Memorandum raises significant procedural concerns, as it cannot amend 

the rule documents

The Cold End Memorandum reflects a significant interpretation of Section 129(g) of the 

CAA. That statement of interpretation, standing alone in a staff memorandum, is insufficient to 

amend the relevant rules, including the CISWI and solid waste definition rules. Therefore, while 

the memorandum is a critical statement of agency interpretation, additional action must be taken 

by EPA to fully resolve the ingredients issue. 

There are statements in the preambles, regulations and response to comment documents 

associated with the CISWI and solid waste definition rules that appear to contradict the Cold End 

Memorandum. In the solid waste definition rule, for example, EPA says that cement kiln dust 

would need to meet the legitimacy criteria to avoid being classified as a solid waste, even if it is 

reused in a closed-loop process.4See, e.g., 76 Fed. Reg. 15517, 15536. Additionally, the solid 

waste definition rule explains how a variety of ingredients used in kilns could be solid waste –

many of which are commonly placed in the cold end of the kiln – without ever making a 

distinction between the “hot” and “cold” ends of the kiln. See, e.g., 76 Fed. Reg. 15536. It is 

difficult to reconcile these and other statements in the rules with the interpretation in the Cold 

End Memorandum.

 

4 As you know, we strongly disagree with this position and intend to seek its reversal through administrative and/or 

judicial processes. Nevertheless, that is the position EPA has currently articulated in its final rule and an agency 

memorandum cannot amend it.
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Even if the rules, preambles, and responses to comments could be read harmoniously 

with the contents of the Cold End Memorandum, there is no trace of that memorandum’s 

interpretations included in any of those rule documents. There is no hint in the thousands of 

pages of those documents that EPA’s position is what is articulated in the Cold End 

Memorandum. Tellingly, the documentation for the solid waste rule and the CISWI rule both 

refuse to address the issue of whether ingredients can be considered combusted, while claiming 

that the issue will be addressed in the other rule. EPA’s response to comments regarding 

ingredients in the solid waste definition rule preamble states that “[w]hether EPA may cover 

ingredients used in combustors under section 129 of the CAA is a matter for regulations under 

that statute,” 76 Fed. Reg. 15536, and in the “Response to Comments” document for the CISWI 

rule, EPA states that the issue is “being dealt with within the Identification of Non-Hazardous 

Secondary Materials That Are Solid Waste rulemaking... [and] will be addressed there.” 

Response to Comments at 74. 

Given the failure to address this issue in the related rulemakings and the high potential 

for conflicts in interpretation, these rules and their preambles will therefore need to be amended 

before anyone could reasonably rely on EPA’s interpretation of Section 129(g) described in the 

Cold End Memorandum. An explanation of EPA’s interpretation should be included in the text 

of the Agency’s decision on the Portland Cement NESHAP reconsideration (as EPA has already 

suggested it would do) and must also be made clear in further rulemaking on the Portland 

Cement NESHAP, the CISWI rule, and the solid waste definition rules. 

2. EPA’s recalculation of the MACT floors is incorrect, as many more than 18 kilns 

are potential CISWI sources

EPA cannot recalculate the Portland Cement Category MACT floors at this time because 

it does not yet know the correct universe of kilns that will be CISWI sources. Even if the Cold 

End Memorandum were procedurally sound and represented EPA’s final interpretation of the 

relevant provisions, the list of cement kilns that may be CISWI sources under the interpretation 

in that memorandum would be several times greater than 18. 

A. Ingredients

As discussed above, the ingredients issue has not yet been fully resolved substantively or 

procedurally. Without resolution of this issue in the relevant rules and preambles, 90% or more 

of the cement kilns may be classified as CISWI sources. If EPA’s interpretation in the Cold End 

Memorandum were to stand unchanged and were properly issued through rulemaking, the effect 

of the ingredients issue would have been ameliorated but not eliminated. Given that roughly 

25% of cement kilns that use alternative ingredients introduce those ingredients at points other 

than the cold end of the kiln, and confusion over how the interpretation applies to pre-heater and 

precaliciner kilns, more than 18 would still be considered CISWI sources based on ingredients 

alone. 

B. Alternative Fuels

Even if EPA were to fully resolve the ingredients issues by promulgating rules that make 

clear that ingredients are not combusted, the total number of cement kilns that will be CISWI 
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sources would still be significantly greater than 18, and in fact could be approximately 80% of 

cement kilns. At least two major alternative fuel issues remain: first, kilns that burn tires that 

may not have been collected exclusively through an established tire collection program as EPA 

has used those terms;5second, kilns that burn a myriad of other alternative fuels that may not 

meet the criteria set forth in the definition of solid waste rule, including biosolids, engineered 

fuels, and others. Even if all tire-derived fuel issues were resolved so that they did not trigger 

CISWI rules, far more than 18 kilns would still be CISWI kilns based on the use of other 

alternative fuels.

In any event, if EPA were to reconsider the Portland Cement NESHAP, it would have to 

do so through notice and comment rulemaking and should, at that time, take into consideration 

(a) the correct list of facilities that will be subject to the NESHAP rule rather than the CISWI 

rule and (b) other emissions data that may become available. It would be wholly inappropriate 

for EPA to deny reconsideration on the basis of the factually flawed MACT floor recalculations 

set forth in the Cold End Memorandum.

3. Conclusions

The Cold End Memorandum does not resolve the “ingredients” issue, leaving the scope 

of application of the CISWI rule to portland cement kilns as vexatious as it was when EPA 

promulgated the Portland Cement NESHAP last year. Even if it had resolved this issue, EPA has 

still not determined the full scope of the facilities that would be CISWI rather than NESHAP 

sources based on their usage of alternative fuels. PCA requests that EPA continue to examine 

this issue and to issue a final interpretation through notice-and-comment rulemaking that 

excludes ingredients entirely from coverage of the CISWI rule, as a proper reading of the Clean 

Air Act mandates. Moreover, PCA urges EPA to grant reconsideration of and stay the Portland 

Cement NESHAP rule as well as the NSPS rule, which includes standards based on the 

NESHAP rule, to allow the Agency time to:

 First, complete the changes to the CISWI and solid waste rules; 

 Second, determine which kilns will be CISWI sources; and 

 Third, engage in appropriate rulemaking to make any changes to the portland 

cement NESHAP and NSPS rules as previously requested by PCA.

Should EPA fail to take the steps necessary to properly promulgate a NESHAP rule that 

does not rely on data from CISWI facilities, the Agency will face the same quandary that the 

D.C. Circuit already addressed once, in the prior Boiler MACT case. When the Court 

determined that “the populations of units subject to EPA’s [NESHAP] and CISWI rules will 

change substantially,” the Court vacated the NESHAP rule, “requiring that EPA recalculate the 

stringency of the emissions standards” to account for the new population of sources. Natural 

 

5 There are several issues with tires. Some companies obtain tires from brokers and do not know the source of all 

tires; some companies do not know whether tire programs in their jurisdictions would qualify as established tire 

collection programs; and finally some companies burn tires that, under EPA’s formulation, have been discarded 

even if they have been managed under an established program.
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Resources Defense Council v. EPA, 489 F.3d 1250, 1261 (D.C. Cir. 2007). EPA should take the 

time to avoid a similar vacatur in this situation. 

Attachment