See the latest EHS federal and state regulatory updates due to COVID-19

On March 21, 2011, in parallel with publication of the Boiler National Emission Standard for Hazardous Air Pollutants (NESHAP) rules and the Non-Hazardous Secondary Material (NHSM) rule, EPA promulgated the final updates to the New Source Performance Standards (NSPS) and Emission Guidelines (EG) for Existing CISWI Units, collectively referred to as the “2011 CISWI Rules.”1  The 2011 CISWI Rules will impact any facility that owns an emission unit that “combusts, or has combusted in the preceding six months, any solid waste as that term is defined in 40 Code of Federal Regulations (CFR) Part 241… .”2  In order to determine if an emission unit combusts non-hazardous solid waste, please refer to the article titled Defining Solid Waste for additional details.

NSPS versus EG

A new CISWI unit is required to comply directly with the NSPS provided under 40 CFR Part 60, Subpart CCCC within six months after promulgation of the rule or upon initial startup, whichever is later.  An existing CISWI unit is required to comply with state-specific regulations that have incorporated the EG (40 CFR Part 60, Subpart DDDD) in a State Plan that has been approved by EPA.  If EPA has not approved the State Plan, the existing CISWI unit must be in compliance with the Federal Plan, as listed in Subpart DDDD.  The existing CISWI unit must be in compliance with the EG within three years after EPA approves a State Plan implementing the EG, or five years after the date Subpart DDDD is promulgated, whichever is earlier.

Key Changes in the Final 2011 CISWI Rules

In response to over 3,500 public comments on the proposed CISWI Rules, EPA made substantial changes from the 2010 proposed rules.  Because industry provided additional emissions and fuel data for combustion sources, EPA re-evaluated all emissions limits previously proposed for new and existing CISWI units.

A summary of the key changes is provided below:

  • Clarified the applicability and compliance requirements for CISWI units that stop or begin combusting solid waste
  • Excluded burn-off ovens, soil treatment units, cyclonic burn barrels, laboratory analysis units, and space heaters from the CISWI Rules
  • Added subcategories for liquid/gas and solid energy recovery units (ERUs)
  • Revised the definition of small, remote incinerators
  • Removed the opacity limits for all subcategories
  • Changed compliance demonstration for continuous emissions monitoring systems (CEMS) to a 30-day rolling average
  • Revised the carbon monoxide (CO) CEMS monitoring requirement from mandatory to voluntary for existing ERUs
  • Added recordkeeping and reporting requirements for units that burn materials other than traditional fuels (as defined in 40 CFR Part 241) to demonstrate that the fuel is not a solid waste
  • Removed the allowance for sources to use the results of previous tests to demonstrate compliance
  • Provided an affirmative defense to civil penalties for exceedances of emission limits that are caused by malfunctions
2011 CISWI Rules
History of the CISWI Rules
  • 2000 - EPA adopted NSPS and EG for CISWI units (2000 CISWI Rules).
  • 2001 - the United States Court of Appeals for the DC Circuit (DC Circuit) granted EPA's voluntary remand, without vacatur, of the definition of "commercial and industrial waste" and "CISWI unit." As such, the definitions included in the 2000 CISWI Rules remain in effect until EPA revises the definitions.
  • 2005 - EPA proposed and finalized the CISWI definitions, which revised the definitions of solid waste, commercial and industrial waste, and CISWI unit (2005 definitions rule).
  • 2007 - the DC Circuit vacated and remanded the 2005 definitions rule. As such, the 2011 regulatory action includes EPA's response to the 2001 voluntary remand of the definitions of "commercial and industrial waste" and "CISWI unit," and EPA's response to the remand and vacatur of the 2005 definitions rule.
  • June 4, 2010 – EPA proposed updates to the 2000 CISWI Rules (2010 Proposed CISWI Rules).
  • December 7, 2010 – EPA requested a 15-month extension to address comments received on the 2010 Proposed CISWI Rules.
  • January 20, 2011 – the DC Circuit rejected EPAs 15-month extension request and required that EPA finalize the CISWI Rules by February 21, 2011.
  • March 21, 2011 – EPA finalized the 2011 CISWI Rules and simultaneously initiated a reconsideration process for certain aspects of the 2011 CISWI Rules.

Applicability and Exemptions
Under the final rule changes, a CISWI unit will be considered a new unit, and therefore, subject to NSPS Subpart CCCC in the following situations:

  1. Construction commences after June 4, 2010, or
  2. Reconstruction or modification commences after September 21, 20113

A CISWI unit will be considered an existing unit, and therefore, subject to state regulations incorporating EG Subpart DDDD in the following scenarios:

  1. Construction commenced on or before June 4, 2010, or
  2. Reconstruction or modification commenced  on or prior to September 21, 2011

Please note that a unit that meets the definition of a new CISWI unit under the 2000 CISWI Rules will be considered an existing CISWI unit under the 2011 CISWI Rules if the unit was constructed on or before June 4, 2010 or modified/reconstructed on or before September 21, 2011.  However, these units would be required to remain in compliance with the 2000 NSPS emission limits as provided in Table 2, until the units are considered existing sources under the amended standards, which would be three years after EPA approved the State Plan or March 21, 2016, whichever is earlier.  State Plans must be submitted to EPA by March 21, 2012.  

The 2011 CISWI Rules exempt the following source types: pathological waste incineration units, municipal waste combustion units, medical waste incineration units, small power production facilities, cogeneration facilities,hazardous waste combustion units, materials recovery units, air curtain incinerators, sewage treatment plants, and sewage sludge incinerators.  The following exemptions were removed from the 2000 CISWI Rules:  agricultural waste incineration units; cyclonic barrel burners; rack, part, and drum reclamation units; cement kilns; chemical recovery units; and laboratory analysis units.  

Additionally, any unit subject to the 2011 CISWI Rules must obtain a Title V operating permit regardless of the potential to emit of any pollutant from the facility.

Cease Combusting Solid Waste?
A CISWI unit is defined as any distinct operating unit of any commercial or industrial facility that combusts, or has combusted in the preceding six months, any solid waste as that term is defined in 40 CFR Part 241.  If a facility opts to stop combusting solid waste, the combustion unit would still be subject to the 2011 CISWI Rules for the subsequent six months.  During this six month time period, the facility must review applicable regulations that the emission unit must comply with when the unit ceases to combust solid waste (e.g. – if a boiler ceased combusting solid waste and was located at a major source of HAPs, the facility would have six months to bring the unit into compliance with the Boiler MACT while remaining in compliance with the 2011 CISWI Rules).  The effective date of the waste-to-fuel switch is at least six months from the date that solid waste was last combusted in the emission unit.  Additionally, the facility must notify EPA 30 days prior to the effective date of switching from solid waste to fuel.  

CISWI Unit Sub-Categories and Emission Limits
The 2010 proposed rule included five source unit subcategories: incinerators, energy recovery units (ERUs), waste-burning kilns, burn-off ovens, and small, remote incinerators. However, in the final rule, EPA removed standards for burn-off ovens and added fuel-specific emission limits for ERUs that combusts biomass, coal, or liquid/gas.  

The final rule establishes emission limits and work practices for the following unit subcategories:

  1. Incinerators – any furnace used in the process of combusting solid waste for the purpose of reducing the volume of the waste by removing combustible matter.
  2. ERU designed to burn biomass – a combustion unit combusting solid waste for energy recovery.  The ERU must combust at least 10 percent biomass, but less than 10 percent coal, on annual average heat input basis, either alone or in combination with liquid waste, liquid fuel, or gaseous fuels.
  3. ERU designed to burn coal – a combustion unit combusting solid waste for energy recovery.  The ERU must combust at least 10 percent coal on annual average heat input basis on an annual average, either alone or in combination with liquid waste, liquid fuel, or gaseous fuels.
  4. ERU designed to burn liquid/gas – a combustion unit combusting solid waste for energy recovery.  The ERU must combust a liquid waste with liquid or gaseous fuels not combined with any solid fuel or waste materials.4
  5. Waste burning kilns – a kiln that is heated, in whole, or in part, by combusting solid waste
  6. Small remote incinerators – an incinerator  that combusts solid waste and combusts three tons of solid waste per day or less and is more than 25 miles driving distance to the nearest municipal solid waste landfill

Based on additional emissions information received during the comment period and the final NHSM rule, EPA revised all emission limits in the final CISWI Rules.  Although EPA established opacity standards in the proposed rule, EPA also requested comment on whether it was appropriate to establish opacity standards for CISWI units.  Based on the comments received, and due to the lack of opacity data from all but one of the CISWI units, EPA determined that it is not appropriate to set opacity standards for CISWI units at this time.  However, in the future, EPA may establish opacity limits for CISWI units, and therefore, is requiring opacity testing as part of the annual testing requirements.

The emissions limits provided in the 2000 CISWI Rules, the 2010 Proposed CISWI Rules, and the 2011 Final CISWI Rules are provided in Table 1 and Table 2.  Table 1 compares limits for existing sources while Table 2 compares limits for new sources.

Consistent with the proposed rule, the final rule requires that facilities comply with emission limits at all times including during times of start-up, shutdown, and malfunction.  For periods of noncompliance during a malfunction, EPA added language in the final rule allowing a facility to use an affirmative defense to civil penalties resulting from an emission limit exceedance.  To assert the claim of affirmative defense, facilities must meet the notification and evaluation criteria provided in the final rules.

Control Devices and Operating Limits
In order to comply with the emission standards provided in Tables 1 and 2, sources will likely have to install one or more control devices on CISWI units.  Consistent with the 2010 Proposed Rules, the 2011 Final CISWI Rules require that the following parameters must be monitored using a continuous parameter monitoring system (CPMS):

  • Wet scrubbers: charge rate, pressure drop or current, scrubber liquid flow rate, andscrubber liquid pH
  • Fabric filters: bag leak detection system
  • Electrostatic precipitators (ESP): secondary voltage and current
  • Activated carbon sorption injection: sorbent flow rate
  • Selective noncatalytic reduction: charge rate, secondary chamber temperature (if applicable to the unit), and reagent flow rate

If a unit does not use a wet scrubber, ESP, or fabric filter to comply with the PM emission limit and if compliance with PM emission limit is not demonstrated with a CEMS, then a unit must maintain opacity less than or equal to 10%.  In addition, if a facility uses control devices other than those specified in this standard or limits emissions in some other manner, the facility must submit a petition to EPA requesting approval of proposed operating parameters that will be monitored and the operating limits that will be established (during the initial performance test) to demonstrate compliance with the emission limits.  The petition must be approved by EPA prior to initial performance testing.  Consistent with the proposed rule, facilities must develop and submit a site-specific monitoring plan for each CPMS required by the rule.  The plan must be submitted at least 60 days before the initial performance evaluation of the continuous monitoring system.  The final rule includes initial and annual inspection requirements for each control device installed on a CISWI.

Source Testing and Continuous Emissions Monitoring
Annual source tests are required for all CISWI units that have an emission limit unless a CEMS is used to demonstrate compliance with the respective emission limit.  The annual performance tests must be conducted between 11 and 13 months of the previous performance test.  The annual performance testing requirements and continuous monitoring requirements are identified in Table 3.

Consistent with the proposed rule, annual performance testing can be reduced to once every three years if test results for at least two consecutive years show emissions at or below 75 percent of the limit for PM, SO2, hydrogen chloride, NOX, lead, cadmium, mercury, and dioxins/furans .  In this case, the performance test must be conducted during the third year and no more than 37 months following the previous performance test for the pollutant.  The results of the annual stack test must be submitted using an EPA web-based electronic reporting tool (ERT) within 60 days of conducting the performance test.  However, due to several concerns addressed during the public comment period regarding the length of time required to submit the ERT data, EPA plans to extend this period from 60 days to 90 days.  


Due to technical concerns raised during the comment period of the 2010 Proposed CISWI Rules, EPA has initiated the reconsideration process for the CISWI rules.  EPA believes that reconsideration and additional opportunity for public review and comment is appropriate because of the major changes that occurred between the 2010 Proposed CISWI Rules and the 2011 CISWI Rules.  Key aspects of the 2011 CISWI Rules that EPA plans to reconsider include the following:

  • Revision of the proposed subcategory for ERU
  • New limitations on fuel switching provisions for CISWI units
  • Revision to the proposed definition of CISWI to exclude cyclonic burn barrels
  • Providing an affirmative defense for malfunction events for CISWI units
  • Revisions to the proposed monitoring requirements for CO

In light of the 2011 Final CISWI Rules and the parallel notice of reconsideration, affected facilities should monitor changes to compliance requirements based on the outcome of the reconsideration notice.

1  Federal Register, Volume 76, Number 54, page 15704
2  Definition of a CISWI unit - 40 CFR 60.2260
3  It appears that 40 CFR 60.2015(a)(1) has an incorrect date of May 20, 2011 for determining if a CISWI unit is a new source.  Consistent with the preamble and the dates provided in Tables 5 through 8 of NSPS Subpart DDDD, it is assumed that a CISWI unit constructed after June 4, 2010 is considered a new unit.
4  It is unclear as to whether EPA intended for ERUs that only combust gaseous waste (and not liquid waste) to fit into this specific subcategory.