The Differences in Implementation Between the HWC MACT Regulation and the PC MACT Regulation as it Affects Hazardous Waste Combusting Cement Kilns Attempting to Comply with Both Regulations.


David L. Constans

Gossman Consulting, Inc.



This paper will present the difference between the PC MACT regulations and the HWC MACT regulations as these regulations impact the cement kilns attempting to comply with both regulations. In particular highlighting the needed changes in implementation required to allow a hazardous waste burning cement kiln to comply with the kiln or kiln/in-line raw mill provisions of the PC MACT regulation when not combusting hazardous waste.


The PC MACT NESHAP’s rule Part 63, Subpart LLL presents the emission standards for the portland cement industry.  This rule is not applicable to kiln and kiln in line raw mills that burn hazardous waste as fuel, which are covered by the HWC MACT rule Part 63, Subpart EEE.  Many kilns subject to the HWC MACT intend to comply with Subpart LLL however when not burning hazardous waste.  There are differences in the two rules which can create compliance and record keeping problems if the facilities are not aware of them.

Differences between HWC MACT and PC MACT

Table 1 below illustrates the differences between the two regulations for existing cement kilns utilizing hazardous waste fuel.  Most of these differences are readily understood from the description in the table; however, a few require some elaboration or explanation. 

Differences in Implementation for Existing Portland Cement Facilities

Hazardous Waste Combustor MACT

Portland Cement MACT


Not “Area” or “Major” Source Sensitive

“Area” and “Major” Sources have different requirements


Requires “by-pass” to have a minimum of 10% of total kiln exhaust gas flowrate

No such requirement for “by-pass”


Many more standards, including metals, destruction efficiency, and CO/THC requirements.  But only one difference in individual standard

- Requires <100 ppmv CO HRA  or <10 ppmv THC HRA in by-pass: Alternately, <100 ppmv CO HRA or <20 ppmv THC HRA in main stack. CEMs required.

Different list of standards for “Area”, “Major” and “New” facilities.  But only the THC standard is different from HWC

- Requires <50 ppmv THC, 30 day block average, in main stack, no CO monitoring alternative. CEMs required. (This is applicable only to “new” kilns or material driers with a “Major” source classification)

Performance Test Plan Requirements

- Initial Comprehensive Performance Test (ICPT) plan required to be submitted for agency review

- No written plan required (though the existence of a plan is assumed) and submittal to the agency is not required except if requested by Regional Administrator

- Content of plan is specified

- Content of plan not specified (though a minimum content of the test report is specified)

- Continuous Monitoring System (CMS) Performance Test Evaluation Plan required and must be submitted in advance of testing

- No CMS Evaluation Plan Required

- Public review of ICPT plan and CMS Evaluation Plan prior to testing

- No requirement for public review of test plans

- With certain restrictions “data-in-lieu-of” may be submitted for the ICPT

- No “data-in-lieu-of” provision in PC MACT


Performance Test Sampling and Analytical Requirements


- Method 0023A

- > 3 hour runs and > 2.5 dscm sample volume

(EPA may address use of Method 23 in future rule changes – FR67 p6870)


- Method 23

- > 3 hour runs and > 2.5 dscm sample volume

HCl / Cl

- Must use Methods 26A, 320 or 321

HCl / Cl

Must use Methods 320 or 321 if intent is to demonstrate “Area Source” status

May use Methods 26 or 26A if not intending to demonstrate “Area Source” status


- Must use Method 5 or 5I


- Must use Method 5

- Runs must be > 1 hour and > 0.85 dscm sample volume, however no “back half” is required


- COM required for kiln and by-pass stack if possible



- COM required for kiln and by-pass stack if possible

- COM required for clinker cooler stack if possible

If “Major Source”

- Method 9 Visual Opacity on all

non-COM dust emission points (Note – Extended test period of 3 hours required, with time reductions for low emission points.)


Monitoring Requirements

A Continuous Monitoring System (CMS) Performance Evaluation Plan (basically a QA/QC plan) is required for all CEMs and non-CEMs which monitor regulated parameters

No CMS Performance Evaluation Plan but extensive Operations and Maintenance Plan (O & M Plan) requirements. 

PCDD/PCDF APCD Inlet Temperature Monitoring Requirements

- Thermocouple calibration as per manufacturer, at least once every 12 months (FR67 p6991)

 - Recorder, no span specified

PCDD/PCDF APCD Inlet Temperature Monitoring Requirements

- Thermocouple calibration at least once every 3 months

 - Recorder, span specified to be zero to 1.5 times the average of the run averages during the performance test.

Area” vs. “Major” source category 

HWC MACT is written without concern for “area” or “major” source considerations. There is a tremendous difference in regulatory requirements for PC MACT kilns considered an “area source” as opposed to a “major source”.

Performance Test Plan Requirements

Clearly the HWC MACT kilns comply with a more specified set of rules for designing and executing their ICPT.  The tendency here would be for the HWC MACT kilns to be lax in planning the PC MACT compliance test and not achieving the operating envelope needed.  It should also be noted that both HWC MACT and PC MACT performance testing is done under normal or representative conditions.

Performance Test Sampling and Analytical Requirements

The differences here are best phrased as:  “A test procedure for one may not be accepted by the other”.  HWC specified the dioxin method as Method 0023A where PC MACT specifies Method 23.  It is likely that the facility could petition  to use method 0023A in place of Method 23.  Also the EPA has stated that an amendment to allow the use of Method 23 as an alternative to Method 0023A will be addressed in a future HWC MACT rule (FR Vol. 67, No. 31 page 6970).  The other differences of note are the differences in methods for particulates and HCl/Cl2.

Monitoring Requirements

HWC kilns must have prepared a continuous monitoring systems (CMS) performance evaluation plan for submittal with their ICPT plan.  Subsequently to performing the ICPT this CMS plan must be utilized to demonstrate compliance with these monitoring requirements on a routine basis.  PC MACT has no such CMS requirement but does have an extensive operations and maintenance (O&M) plan requirement.  In addition, the PC MACT rules specify requirements for continuous opacity monitors and visible emissions testing. 

There are two items where the two regulations disagree: the thermocouples monitoring temperatures in the entrance to the APCD in PC MACT kilns must be calibrated every 3 months by a specified method, whereas HWC MACT kilns must perform this task per the manufacture’s specification at least once every 12 months.  (see FR Vol.  No.  6991) Additionally, PC MACT specifies the range of the recorder of the ACPD inlet temperature as 1.5 times the average of the sum determined in the performance test.  Neither of these differences should be a problem to comply with as long as the facility is aware of them and makes allowance for them.

Complying With PC MACT When Not Burning Hazardous Waste Fuel

In the amendments to the HWC MACT rule released on February 14 (FR Vol. 67 No. 31 Pages 6968 - 6996), the EPA significantly rewrote 63.1209 (q) - Monitoring requirements operating under different modes of operation.  In the preamble to these amendments the EPA clarified the manner in which the facility is to demonstrate compliance, temporarily, with alternative or otherwise applicable MACT standards.  To do this the facility must establish an operating mode for this period when hazardous wastes are not burned (and the residence time has expired) and must specify the operating parameters for the mode of operation consistent with the alternate PC MACT standard. 

Specification of the PC MACT requirements is required since the facility remains under Subpart EEE even though waste is not being burned.  Consequently for technical purposes unless the operating parameters are specified they are not enforceable.  If an alternative applicable requirement is not specified then Subpart EEE must apply. 

EPA has made it clear in both the Preamble to the February 14 amendments and in e-mail correspondence that if a facility chooses to comply with the PC MACT requirements when not burning waste they must “…include all requirements of those MACT standards, not just operating limits…” (FR Vol. 67, No. 31, page 6979, VIII)

Concluding Remarks

The implementation differences between PC MACT and HWC MACT are not large but the facility must be careful in selecting test methods and in meeting the different monitoring requirements.  With careful planning the amount of testing can be minimized.