4 The record articles

Compliance Considerations for Chemical Recovery Combustion Sources at Pulp & Paper Mills

Posted: April 23rd, 2020

Authors: Lindsey K. 
quarantine articles series logo

This article is part of ALL4’s 4 The Record: Quarantine Series.

The compliance date for amendments to 40 CFR Part 63, Subpart MM (National Emission Standards for Hazardous Air Pollutants for Chemical Recovery Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills) was on October 11, 2019, but that was not the end of compliance-related activities.  The first periodic performance test is due by October 13, 2020, and while that may seem straightforward, there are several considerations around both testing and other parts of the rule, and the current COVID-19 National Emergency adds another layer of complexity.

40 CFR Part 63, Subpart MM regulates recovery furnaces, smelt dissolving tanks, and lime kilns at most pulp and paper mills, and establishes emissions limits for particulate matter (PM) and, for some sources, methanol or total hydrocarbons (THC).  This article presents some routine considerations for testing, rule-related considerations, and COVID-19 considerations.


As with any performance test, primary deliverables include notifications, as well as a test protocol, test plan, and test report.  Each item is discussed further below.


Notification requirements for the performance test and performance evaluation(s) are specified in the General Provisions under 40 CFR §§63.7 and 63.8, respectively.  Notification of the performance test is required at least 60 days in advance of the scheduled test date, and notification of the performance evaluation should be submitted simultaneously.  The notifications should typically be sent to the appropriate U.S. EPA Regional Office and your local air quality regulatory agency (referred to going forward as “state agency”).  Your state agency may have additional notification requirements, so be sure to check your permit and any applicable regulations.

Test Protocol

The test protocol is typically developed by your stack testing firm, and many state agencies require it to be submitted with the notification.  The test protocol contains a description of the procedures, test methods, analytical methods, calculations, quality assurance procedures, etc. that the stack testing firm will use to conduct the test and to analyze the results.

Test Plan

The test plan for the performance test and performance evaluation is typically developed by the mill and sometimes in conjunction with the stack testing firm.  The test plan contains a description of the sources being tested, how the mill will operate, how data will be recorded, designated personnel, etc.  While the test plan is not required to be submitted, it may be requested, so it’s recommended to have it developed at the time of the 60-day notification.

The performance evaluation(s) of continuous monitoring systems (CMS) should be conducted prior to the performance test (e.g., scrubber flow rates, pressure drop, fan amperage).  Neither the rule nor the General Provisions define how far in advance of the performance test the performance evaluations must be conducted, but for CMS that can be evaluated without a process shutdown, within 30 days is reasonable.  The purpose of CMS performance evaluations is to ensure the validity of the parametric data collected during the performance test, because that data is used to establish operating limits.  A CMS performance evaluation typically involves a calibration or other independent verification of the CMS output.

40 CFR Part 63, Subpart MM states that operating limits must be “confirmed or reestablished” during performance tests, and goes on to include terms such as “new,” “expanded,” or “replacement” operating limits.  None of these terms are defined in the rule, so we recommend establishing a mill-specific procedure for confirming or reestablishing operating limits in advance, but it’s possible that your state agency will require an update of the operating limits based on the most recent performance test, regardless of whether you intended to simply confirm them.

Test Report

Within 60 days following the performance test, the test report must be submitted via U.S. EPA’s Compliance and Emissions Data Reporting Interface (CEDRI) using the Electronic Reporting Tool (ERT).    Your state agency may also still require submittal of a hard copy test report.  Be sure to understand whether submittal of the test report will be completed by the mill or the stack testing firm, and to receive a draft of the test report with enough time to adequately review the results prior to the 60-day submittal deadline.

More information about performance testing can be found here.


Additional amendments to 40 CFR Part 63, Subpart MM were proposed on October 31, 2019, that primarily pertained to corrections and clarifications, but the most significant proposed amendment pertained to the method for establishing the smelt dissolving tank scrubber fan amperage minimum operating limit (where fan amperage is monitored instead of pressure drop).  Mills expressed concern with the promulgated method of using the lowest hourly average fan amperage during the performance test.  The proposed amendments updated the rule to provide three alternatives, but all options included new, additional provisions to operate the scrubber fan within 5% of the design revolutions per minute (RPM).  Due to the age of these scrubbers, many mills may not know the design RPM of the fan or have the capability to measure RPMs during the performance test.  Objections to this new requirement have been submitted with comments on the proposed rule, but until the rule is finalized, mills that intend to establish an operating limit for fan amperage during the performance test face uncertainty about how to set it.  More information on the proposed amendments can be found here.

On April 21, 2020, the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit Court) remanded 40 CFR Part 63, Subpart MM back to U.S. EPA (without vacatur) in order to establish emissions limits for previously unregulated hazardous air pollutants (HAPs) that are known to be emitted from the pulp and paper mill chemical recovery combustion source category.  40 CFR Part 63, Subpart MM currently regulates PM as a surrogate for HAP metals, and methanol (for new kraft and soda recovery furnaces) or THC (for semichemical combustion units) as a surrogate for gaseous organic HAPs.  However, Subpart MM does not contain standards for all existing chemical recovery combustion source HAP emissions, which can include mercury (Hg), dioxins and furans (D/F), non-dioxin organic HAP, hydrogen chloride (HCl), and hydrogen fluoride (HF).  Stay tuned for more on this topic, as it also has far-reaching implications for other rules that do not have emissions limits for all HAPs emitted from a particular source category.


Even before the COVID-19 National Emergency, mills expressed concern over the availability of stack testing firms due to all mills across the country subject to 40 CFR Part 63, Subpart MM needing to test their chemical recovery combustion sources by October 2020.  This concern was further elevated due to the uncertainty around whether the updated procedures for setting the smelt dissolving tank scrubber fan amperage operating limit would be finalized for mills using fan amperage instead of pressure drop.  With travel and onsite personnel restrictions now in place due to COVID-19, more mills will likely be testing even later in the year than originally planned.  This, along with other non-pulp and paper facilities also delaying testing due to COVID-19, is expected to further limit the availability of stack testing firms.

As with all COVID-19-related guidance, we suggest doing as much as possible to maintain compliance and meet notification and testing deadlines.  Should you find that COVID-19 directly impacts your ability to comply with the October 2020 testing deadline due to the limitations described above, document everything you can, and contact your state agency about the possibility of a compliance extension due to force majeure, a test waiver, or enforcement discretion in accordance with U.S. EPA’s published policy and your particular state agency’s position.  More information about U.S. EPA’s enforcement discretion policy can be found here.



    Sign up to receive 4 THE RECORD articles here. You'll get timely articles on current environmental, health, and safety regulatory topics as well as updates on webinars and training events.
    First Name: *
    Last Name: *
    Location: *
    Email: *

    Skip to content