197 Considering these factors and cost effectiveness, we conclude that a beyond the floor standard is not warranted. Therefore, we propose a semivolatile metals standard based on the floor level: 4.3E 6 lbs semivolatile metals emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste for new sources. E. What Is the Rationale for the Proposed Standards for Chromium? We propose to establish standards for existing and new liquid fuel fired boilers that limit emissions of chromium to 1.1E 4 lbs and 3.6E 5 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste, respectively. We propose to establish emission standards on chromium only because our data base has very limited compliance test data on emissions of total low volatile metals: arsenic, beryllium, and chromium. We have compliance test data on only two sources for total low volatile metals emissions while we have compliance test data for 12 sources for chromium only. Although we have total low volatile metals emissions for 12 sources when operating under normal operations, we prefer to use compliance test data to establish the floor because they better address emissions variability. By establishing a low volatile metal floor based on chromium emissions only we are relying on the particulate matter standard to control the other enumerated low volatile metals arsenic and beryllium as well as nonenumerated metal HAP. We request comment on this approach and note that, as discussed below, an alternative approach would be to establish a MACT floor based on normal emissions data for all three enumerated low volatile metals. We request comment on whether the compliance test data for chromium only are appropriate for establishing a MACT floor for chromium. We are concerned that some sources in our data base may have used chromium as a surrogate for arsenic and beryllium during RCRA compliance testing such that their chromium emissions may be more representative of their total low volatile metals emissions than only chromium. If we determine this to be the case, we could apply the floor we calculate using chromium emissions to total low volatile metal emissions. Alternatively, we could use the normal emissions data we have on 12 sources and our MACT methodology to establish a total low volatile metals floor. 1. What Is the Rationale for the MACT Floor for Existing Sources? MACT floor for existing sources is 1.1E 4 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste, which is based on particulate matter control ( for those few sources using a control device) and controlling the feed concentration of chromium in the hazardous waste. We have compliance test emissions data representing maximum emissions for approximately 17% of the sources. 52 The compliance test chromium stack emissions in our database range from 2 to 900 ug/ dscm. These emissions are expressed as mass of chromium * OMB Review Draft*

198 ( from all feedstocks) per unit of stack gas. Hazardous waste thermal emissions, available for 13% of sources, range from 3.2E 6 to 8.8E 4 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. To identify the floor level, we evaluated all compliance test thermal emissions data using the SRE/ Feed Approach ( see discussion in Section VI. C above). The calculated floor is 1.1E 4 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste feed, which considers emissions variability. This is an emission level that the average of the best performing sources could be expected to achieve in 99 of 100 future tests when operating under conditions identical to the compliance test conditions during which the emissions data were obtained. We estimate that this floor level is being achieved by 36% of sources and would reduce chromium emissions by 9.4 tons per year. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We identified two potential beyond the floor techniques for control of chromium emissions: ( 1) use of a fabric filter to improve particulate matter control; and ( 2) control of chromium in the hazardous waste feed. For reasons discussed below, we are not proposing a beyond the floor standard for chromium. a. Use of a Fabric Filter to Improve Particulate Matter Control. We evaluated use of a fabric filter as beyond the floor control for further reduction of chromium emissions. We evaluated a beyond the floor level of 5.5E 5 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. The national incremental annualized compliance cost for liquid fuel fired boilers to meet this beyond the floor level rather than comply with the floor controls would be approximately $ 5.9 million and would provide an incremental reduction in chromium emissions beyond the MACT floor controls of 0.50 tons per year. We evaluated nonair quality health and environmental impacts and energy effects and determined that this beyond the floor option would increase the amount of hazardous waste generated by approximately 160 tons per year and would increase electricity usage by 3.0 million kW hours per year. Based on these impacts and a cost of approximately $ 12 million per additional ton of chromium removed, we are not proposing a beyond the floor standard based on improved particulate matter control. b. Feed Control of Chromium in the Hazardous Waste. We evaluated additional feed control of chromium in the hazardous waste as a beyond the floor control technique to reduce floor emission levels by 25% to achieve a standard of 8.8E 5 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. This beyond thefloor level of control would reduce chromium by an additional 0.20 tons per year at a costeffectiveness of $ 22 million per ton of chromium removed. Nonair quality health and environmental impacts and energy effects are not significant factors for feedrate control. We conclude that use of additional hazardous waste chromium feedrate control would not be costeffective and are not proposing a beyond the floor standard based on this control technique. For the reasons discussed above, we do not propose a beyond the floor standard for chromium. Consequently, we propose to establish the emission standard for existing liquid fuelfired boilers at the floor level: a hazardous waste thermal emission standard of 1.1E 4 lbs chromium emissions attributable to hazardous waste per million Btu of hazardous waste feed. * OMB Review Draft*

199 3. What Is the Rationale for the MACT Floor for New Sources? The MACT floor for new sources for chromium would be 3.6E 5 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste feed. This is an emission level that the single best performing source identified with the SRE/ Feed Approach could be expected to achieve in 99 of 100 future tests when operating under operating conditions identical to the compliance test conditions during which the emissions data were obtained. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources We evaluated use of an advanced fabric filter using high efficiency membrane bag material and a low air to cloth ratio as beyond the floor control to reduce chromium emissions to a beyond the floor level of 1.8E 5 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. The incremental annualized compliance cost for a new liquid fuel fired boiler with average gas flowrate to meet this beyond the floor level, rather than comply with the floor level, would be approximately $ 0.15 million and would provide an incremental reduction in chromium emissions of 0.014 tons per year, for a cost effectiveness of $ 11 million per ton of chromium removed. We evaluated the nonair quality health and environmental impacts and energy effects of this beyond the floor standard and estimate that, for a new liquid fuel fired boiler with average gas flowrate, the amount of hazardous waste generated would increase by 2 tons per year and electricity consumption would increase by 0.54 million kWhours per year. Considering these factors and cost effectiveness, we conclude that a beyond thefloor standard is not warranted. Therefore, we propose a chromium emission standard for new sources based on the floor level: 3.6E 5 lbs chromium emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste feed. F. What Is the Rationale for the Proposed Standards for Total Chlorine? We are proposing to establish a standard for existing liquid fuel fired boilers that limit emissions of hydrogen chloride and chlorine gas ( i. e., total chlorine) to 2.5E 2 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. The proposed standard for new sources would be 7.2E 4 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. 1. What Is the Rationale for the MACT Floor for Existing Sources? Most liquid fuel fired boilers that burn hazardous waste do not have back end controls such as wet scrubbers for total chlorine control. For these sources, total chlorine emissions are controlled by most sources by controlling the feedrate of chlorine in the hazardous waste feed. Approximately 15% of sources use wet scrubbing systems to control total chlorine emissions. We have compliance test data representing maximum emissions for 40% of the boilers. Total chlorine emissions range from less than 1 to 900 ppmv. Hazardous waste thermal emissions, available for 27% of boilers, range from 1.00E 4 to 1.4 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. The calculated floor is 2.5E 2 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste using the SRE/ Feed Approach to identify the best performing sources ( see discussion in Section VI. C above). This is an emission level that the average of the performing sources could be expected to achieve in 99 of 100 future * OMB Review Draft*

200 tests when operating under operating conditions identical to the compliance test conditions during which the emissions data were obtained. We estimate that this floor level is being achieved by 70% of sources and would reduce total chlorine emissions by 660 tons per year. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We identified two potential beyond the floor techniques for control of total chlorine emissions: ( 1) use of a wet scrubber; and ( 2) control of chlorine in the hazardous waste feed. For reasons discussed below, we are not proposing a beyond the floor standard for total chlorine. a. Use of Wet Scrubbing. We considered a beyond the floor standard of 1.3E 2 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste based on wet scrubbing to reduce emissions beyond the floor level by 50 percent. The national incremental annualized compliance cost for liquid fuel fired boilers to meet this beyond the floor level rather than comply with the floor controls would be approximately $ 7.8 million and would provide an incremental reduction in total chlorine emissions beyond the MACT floor controls of 430 tons per year. We evaluated nonair quality health and environmental impacts and energy effects and determined that this beyond the floor option would increase both the amount of hazardous wastewater generated and water usage by approximately 3.2 billion gallons per year and would increase electricity usage by 30 million kW hours per year. Considering these impacts and a cost effectiveness of approximately $ 18,000 per additional ton of total chlorine removed, we are not proposing a beyond the floor standard based on wet scrubbing. b. Feed Control of Chromium in the Hazardous Waste. We evaluated additional feed control of chlorine in the hazardous waste as a beyond the floor control technique to reduce floor emission levels by 20% to achieve a standard of 2.0E 2 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. The national incremental annualized compliance cost for liquid fuel fired boilers to meet this beyond the floor level rather than comply with the floor controls would be approximately $ 3.9 million and would provide an incremental reduction in total chlorine emissions beyond the MACT floor controls of 170 tons per year. Nonair quality health and environmental impacts and energy effects are not significant factors for feedrate control. We conclude that use of additional hazardous waste chlorine feedrate control would not be cost effective at $ 23,000 per ton of total chlorine removed and are not proposing a beyond the floor standard based on this control technique. For the reasons discussed above, we propose a total chlorine standard for existing liquid fuel fired boilers based on the floor level: 2.5E 2 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. 3. What Is the Rationale for the MACT Floor for New Sources? The MACT floor for new sources for total chlorine would be 7.2E 4 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. This is an emission level that the single best performing source identified with the SRE/ Feed Approach could be expected to achieve in 99 of 100 future tests when operating under operating conditions identical to the compliance test conditions during which the emissions data were obtained. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources * OMB Review Draft*

201 We evaluated wet scrubbing as beyond the floor control for further reductions in total chlorine emissions to achieve a beyond the floor level of 3.6E 4 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. The incremental annualized compliance cost for a new liquid fuel fired boiler with an average gas flowrate to meet this beyond the floor level, rather than comply with the floor level, would be approximately $ 0.44 million and would provide an incremental reduction in total chlorine emissions of approximately 0.13 tons per year, for a cost effectiveness of $ 3.3 million per ton of total chlorine removed. We evaluated nonair quality health and environmental impacts and energy effects and determined that, for a new source with average an average gas flowrate, this beyondthe floor option would increase both the amount of hazardous wastewater generated and water usage by approximately 140 million gallons per year and would increase electricity usage by 1.3 million kW hours per year. After considering these impacts and cost effectiveness, we conclude that a beyond the floor standard based on wet scrubbing for new liquid fuel fired boilers is not warranted. For the reasons discussed above, we propose a total chlorine standard for new sources based on the floor level: 7.2E 4 lbs total chlorine emissions attributable to the hazardous waste per million Btu heat input from the hazardous waste. G. What Is the Rationale for the Proposed Standards for Carbon Monoxide or Hydrocarbons? To control emissions of organic HAP, existing and new sources would be required to comply with either a carbon monoxide standard of 100 ppmv or a hydrocarbon standard of 10 ppmv. 1. What Is the Rationale for the MACT Floor for Existing Sources? Liquid fuel fired boilers that burn hazardous waste are currently subject to RCRA standards that require compliance with either a carbon monoxide standard of 100 ppmv, or a hydrocarbon standard of 20 ppmv. Compliance is based on an hourly rolling average as measured with a CEMS. See § 266.104( a). We are proposing today floor standards of 100 ppmv for carbon monoxide or 10 ppmv for hydrocarbons. Floor control for existing sources is operating under good combustion practices including: ( 1) providing adequate excess air with use of oxygen CEMS and feedback air input control; ( 2) providing adequate fuel/ air mixing; ( 3) homogenizing hazardous waste fuels ( such as by blending or size reduction) to control combustion upsets due to very high or very low volatile content wastes; ( 4) regulating waste and air feedrates to ensure proper combustion temperature and residence time; ( 5) characterizing waste prior to burning for combustion related composition ( including parameters such as heating value, volatile content, liquid waste viscosity, etc.); ( 6) ensuring the source is operated by qualified, experienced operators; and ( 7) periodic inspection and maintenance of combustion system components such as burners, fuel and air supply lines, injection nozzles, etc. Given that there are many interdependent parameters that affect combustion efficiency and thus carbon monoxide and hydrocarbon emissions, we are not able to quantify " good combustion practices." All liquid fuel fired boilers are currently complying with the RCRA carbon monoxide limit of 100 ppmv on an hourly rolling average. No boilers are complying with the RCRA hydrocarbon * OMB Review Draft*

202 limit of 20 ppmv on an hourly rolling average. We propose a floor level for carbon monoxide level of 100 ppmv because it is a currently enforceable Federal standard. Although the best performing sources are achieving carbon monoxide levels below 100 ppmv, it is not appropriate to establish a lower floor level because carbon monoxide is a surrogate for nondioxin/ furan organic HAP. As such, lowering the carbon monoxide floor may not significantly reduce organic HAP emissions. In addition, it would be inappropriate to apply a MACT methodology to the carbon monoxide emissions from the best performing sources because those sources may not be able to replicate their emission levels. This is because there are myriad factors that affect combustion efficiency and, subsequently, carbon monoxide emissions. Extremely low carbon monoxide emissions cannot be assured by controlling only one or two operating parameters We note also that we used this rationale to establish a carbon monoxide standard of 100 ppmv for Phase I sources in the September 1999 Final Rule. We propose a floor level for hydrocarbons of 10 ppmv even though the currently enforceable standard is 20 ppmv because: ( 1) the two sources that comply with the RCRA hydrocarbon standard can readily achieve 10 ppmv; and ( 2) reducing hydrocarbon emissions within the range of 20 ppmv to 10 ppmv should reduce emissions of nondioxin/ furan organic HAP. We do not apply a prescriptive MACT methodology to establish a hydrocarbon floor below 10 ppmv, however, because we have data from only two sources. In addition, we note that the hydrocarbon emission standard for Phase I sources established in the September 1999 Final Rule is 10 ppmv also. There would be no incremental emission reductions associated with these floors because all sources are currently achieving the floor levels. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We considered beyond the floor levels for carbon monoxide and hydrocarbons based on use of better combustion practices but conclude that they may not be replicable by the best performing sources nor duplicable by other sources given that we cannot quantify good combustion practices. Moreover, as discussed above, we cannot ensure that lower carbon monoxide or hydrocarbon levels would significantly reduce emissions of nondioxin/ furan organic HAP. Nonair quality health and environmental impacts and energy requirements are not significant factors for use of better combustion practices as beyond the floor control. For these reasons, we conclude that beyond the floor standards for carbon monoxide and hydrocarbons are not warranted for existing sources. 3. What Is the Rationale for the MACT Floor for New Sources? MACT floor for new sources would be the same as the floor for existing sources 100 ppmv for carbon monoxide and 10 ppmv for hydrocarbons and based on the same rationale. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources As discussed in the context of beyond the floor considerations for existing sources, we considered beyond the floor standards for carbon monoxide and hydrocarbons for new sources based on use of better combustion practices. But we conclude that beyond the floor standards may not be replicable by the best performing sources nor duplicable by other sources given that we cannot quantify good combustion practices. Moreover, we cannot ensure that lower carbon * OMB Review Draft*

53 The carbon monoxide/ hydrocarbon emission standard would control organic HAP that are products of incomplete combustion by also ensuring use of good combustion practices.

203 monoxide or hydrocarbon levels would significantly reduce emissions of nondioxin/ furan organic HAP. Nonair quality health and environmental impacts and energy requirements are not significant factors for use of better combustion practices as beyond the floor control. For these reasons, we are not proposing a beyond the floor standard for carbon monoxide and hydrocarbons. H. What Is the Rationale for the Proposed Standard for Destruction and Removal Efficiency? To control emissions of organic HAP, existing and new sources would be required to comply with a destruction and removal efficiency ( DRE) of 99.99% for organic HAP. For sources burning hazardous wastes F020, F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% for organic HAP. 1. What Is the Rationale for the MACT Floor for Existing Sources? Liquid fuel fired boilers that burn hazardous waste are currently subject to RCRA DRE standards that require 99.99% destruction of designated principal organic hazardous constituents ( POHCs). For sources that burn hazardous wastes F020, F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% destruction of designated POHCs. See § 266.104( a). The DRE standard helps ensure that a combustor is operating under good combustion practices and thus minimizing emissions of organic HAP. Under the MACT compliance regime, sources would designate POHCs that are organic HAP or that are surrogates for organic HAP. We propose to establish the RCRA DRE standard as the floor for existing sources because it is a currently enforceable Federal standard. There would be no incremental costs or emission reductions associated with this floor because sources are currently complying with the standard. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We considered a beyond the floor level for DRE based on use of better combustion practices but conclude that it may not be replicable by the best performing sources nor duplicable by other sources given that we cannot quantify better combustion practices. Moreover, we cannot ensure that a higher DRE standard would significantly reduce emissions of organic HAP given that DRE measures the destruction of organic HAP present in the boiler feed rather than gross emissions of organic HAP. Although a source's combustion practices may be adequate to destroy particular organic HAP in the feed, other organic HAP that may be emitted as products of incomplete combustion may not be controlled by the DRE standard. 53 For these reasons, and after considering nonair quality health and environmental impacts and energy requirements, we are not proposing a beyond the floor DRE standard for existing sources. 3. What Is the Rationale for the MACT Floor for New Sources? We propose to establish the RCRA DRE standard as the floor for new sources because it is a currently enforceable Federal standard. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources * OMB Review Draft*

204 Using the same rationale as we used to consider a beyond the floor DRE standard for existing sources, we conclude that a beyond the floor DRE standard for new sources is not warranted. Consequently, after considering nonair quality health and environmental impacts and energy requirements, we are proposing the floor DRE standard for new sources.

XII. How Did EPA Determine the Proposed Emission Standards for Hazardous Waste Burning Hydrochloric Acid Production Furnaces? The proposed standards for existing and new hydrochloric acid production furnaces that burn hazardous waste are summarized in the table below. See proposed § 63.1218.

PROPOSED STANDARDS FOR EXISTING AND NEW HYDROCHLORIC ACID PRODUCTION FURNACES Hazardous Air Pollutant or Surrogate Emission Standard1 Existing Sources New Sources Dioxin and furan 0.40 ng TEQ/ dscm 0.40 ng TEQ/ dscm Hydrochloric acid and chlorine gas2 14 ppmv or 99.9927% System Removal Efficiency or the alternative emission limits under § 63.1215 1.2 ppmv or 99.99937% System Removal Efficiency or the alternative emission limits under § 63.1215 Carbon monoxide or hydrocarbons3 100 ppmv carbon monoxide or 10 ppmv hydrocarbons 100 ppmv carbon monoxide or 10 ppmv hydrocarbons Destruction and Removal Efficiency For existing and new sources, 99.99% for each principal organic hazardous constituent ( POHC). For sources burning hazardous wastes F020, F021, F022, F023, F026, or F027, however, 99.9999% for each POHC.

1 All emission standards are corrected to 7% oxygen, dry basis. 2 Combined standard, reported as a hydrogen chloride equivalent. 3 Hourly rolling average. Hydrocarbons reported as propane.

A. What Is the Rationale for the Proposed Standards for Dioxin and Furan? The proposed standard for doixin/ furan for existing and new sources is 0.40 ng TEQ/ dscm. 1. What Is the Rationale for the MACT Floor for Existing Sources? The proposed MACT floor for existing sources is compliance with the proposed CO/ HC emission standard and compliance with the proposed DRE standard. Hydrochloric acid production furnaces use wet scrubbers to remove hydrochloric acid from combustion gases to produce the hydrochloric acid product and to minimize residual * OMB Review Draft*

54 Section 266.104 requires compliance with a carbon monoxide limit of 100 ppmv or a hydrocarbon limit of 20 ppmv, while we are proposing today a carbon monoxide limit of 100 ppmv or a hydrocarbon limit of 10 ppmv ( see Section XII. H in the text). Although today's proposed hydrocarbon limit is more stringent than the current limit for hydrochloric acid production furnaces, all sources chose to comply with the 100 ppmv carbon monoxide limit.

205 emissions of hydrochloric acid and chlorine gas. Thus, dioxin/ furan cannot be formed on particulate surfaces in the emission control device as can happen with electrostatic precipitators and fabric filters. Nonetheless, dioxin/ furan emissions from hydrochloric acid production furnaces can be very high. We have dioxin/ furan emissions data for 18 test conditions representing 14 of the 17 sources. Dioxin/ furan emissions range from 0.02 ng TEQ/ dscm to 6.8 ng TEQ/ dscm. We investigated whether it would be appropriate to establish separate dioxin/ furan standards for furnaces equipped with waste heat recovery boilers versus those without boilers. Ten of the 17 hydrochloric acid production furnaces are equipped with boilers. We considered whether waste heat recovery boilers may be causing the elevated dioxin/ furan emissions, as appeared to be the case for incinerators equipped with boilers. See 62 FR at 24220 ( May 2, 1997) where we explain that heat recovery boilers preclude rapid temperature quench of combustion gases, thus allowing particle catalyzed formation of dioxin/ furan. The dioxin/ furan data for hydrochloric acid production furnaces indicate, however, that furnaces with boilers have dioxin/ furan emissions ranging from 0.05 to 6.8 ng TEQ/ dscm, while furnaces without boilers have dioxin/ furan emissions ranging from 0.02 to 1.7 ng TEQ/ dscm. Based on a statistical analysis of the data sets ( see discussion in Part Two, Section II. E), we conclude that the dioxin/ furan emissions for furnaces equipped with boilers are not significantly different from dioxin/ furan emissions for furnaces without boilers. Thus, we conclude that separate dioxin/ furan emission standards are not warranted. We cannot or identify or quantify a dioxin/ furan control mechanism for these furnaces. Consequently, we conclude that establishing a floor emission level based on emissions from the best performing sources would not be appropriate because the best performing sources may not be able to replicate their emission levels, and other sources may not be able to duplicate those emission levels. We note, however, that dioxin/ furan emissions can be affected by the furnace's combustion efficiency. Operating under poor combustion conditions can generate dioxin/ furan and organic precursors that may contribute to post combustion dioxin/ furan formation. Because we cannot quantify a dioxin/ furan floor level and because hydrochloric acid production furnaces are currently required to operate under good combustion practices by RCRA standards for carbon monoxide/ hydrocarbons and destruction and removal efficiency, we identify those RCRA standards as the proposed MACT floor. See § 266.104 requiring compliance with destruction and removal efficiency and carbon monoxide/ hydrocarbon emission standards. 54 We also find, as required by CAA Section 112( h)( 1), that these proposed standards are consistent with Section 112( d)' s objective of reducing emissions of these HAP to the extent achievable. We also request comment on an alternative MACT floor expressed as a dioxin/ furan * OMB Review Draft*

55 USEPA, " Draft Technical Support Document for HWC MACT Replacement Standards, Volume III: Selection of MACT Standards and Technologies," March 2004.

56 Please note that, under the proposed floor level, sources would not incur retrofit costs or achieve dioxin/ furan emissions reductions because they currently comply with the floor controls under current RCRA regulations at 40 CFR 266.104.

206 emission concentration. Although it would be inappropriate to identify a floor concentration based on the average emissions of the best performing sources as discussed above, we could identify the floor as the highest emission concentration from any source in our data base, after considering emissions variability. Under this approach, the highest emitting source could be expected to achieve the floor 99 out of 100 future tests when operating under the same conditions as it did when the emissions data were obtained. A floor that is expressed as a dioxin/ furan emission level would prevent sources from emitting at levels higher than the ( currently) worstcase source ( actually, the worst case performance test result) currently emits. We specifically request comment on this alternative MACT floor. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We evaluated use of an activated carbon bed ( preceded by gas reheating to above the dewpoint) as beyond the floor control for dioxin/ furan. Carbon beds can achieve greater than 99% reduction in dioxin/ furan emissions. 55 We considered alternative beyond the floor levels of 0.40 ng TEQ/ dscm and 0.20 ng TEQ/ dscm. The incremental annualized cost of a beyond the floor emission level of 0.40 ng TEQ/ dscm would be $ 1.9 million and would provide an incremental reduction in dioxin/ furan emissions of 2.3 grams TEQ per year, for a cost effectiveness of $ 0.82 million per gram TEQ removed. 56 A beyond the floor emission level of 0.20 ng TEQ/ dscm would provide very little incremental emissions reduction 0.1 grams TEQ per year at additional costs. We evaluated nonair quality health and environmental impacts and energy effects and determined that this beyond the floor option would increase the amount of hazardous wastewater generated by 210 tons per year, and would increase electricity usage by 1.8 million kW hours per year and natural gas consumption by 96 trillion Btu per year. Notwithstanding these impacts, we conclude that a beyond the floor level of 0.40 ng TEQ/ dscm would be warranted considering the special hazard dioxin/ furan emissions pose. For the reasons discussed above, we are proposing a beyond the floor standard for dioxin/ furan of 0.40 ng TEQ/ dscm for existing sources. Thirty five percent of sources are currently meeting this standard. 3. What Is the Rationale for the MACT Floor for New Sources? MACT floor for new sources is the same as for existing sources under the same rationale: compliance with the carbon monoxide/ hydrocarbon emission standard and compliance with the destruction and removal efficiency standard. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources As for existing sources, we evaluated use of an activated carbon bed as beyond the floor * OMB Review Draft*

57 We estimate beyond the floor control costs assuming a new source emits the highest levels likely under floor control based on compliance with the carbon monoxide and destruction and removal efficiency standards.

58 USEPA, " Draft Technical Support Document for HWC MACT Replacement Standards, Volume III: Selection of MACT Standards and Technologies," March 2004.

59 Except that one source emitted 330 ug/ dscm low volatile metals and 0.043 gr/ dscf particulate matter during compliance testing. This source apparently detuned the acid gas absorber and other acid gas control equipment given that it achieved less than 99% system removal efficiency for total chlorine and had total chlorine emissions of 500 ppmv. This source 207 control for new sources to achieve an emission level of 0.40 ng TEQ/ dscm. We estimate that the incremental annualized cost for a new hydrochloric acid production furnace with average gas flowrate to reduce dioxin/ furan emissions at the floor of 0.68 ng TEQ/ dscm57 to achieve a beyond the floor emission level of 0.40 ng TEQ/ dscm would be $ 0.15 million. These controls would provide an incremental reduction in dioxin/ furan emissions of 0.66 grams TEQ per year, for a cost effectiveness of $ 230,000 per gram TEQ removed. We evaluated nonair quality health and environmental impacts and energy effects and determined that, for a new source with average an average gas flowrate, this beyond the floor option would increase the amount of hazardous wastewater generated by 9 tons per year, and would increase electricity usage by 0.14 million kW hours per year and natural gas consumption by 9.2 trillion Btu per year. Notwithstanding these impacts, we conclude that a beyond the floor level of 0.40 ng TEQ/ dscm would be costeffective considering the special hazard dioxin/ furan emissions pose. For these reasons, we propose a beyond the floor standard for dioxin/ furan for new sources of 0.40 ng TEQ/ dscm. B. What Is the Rationale for the Proposed Standards for Mercury, Semivolatile Metals, and Low Volatile Metals? We propose to require compliance with the total chlorine standard as a surrogate for the mercury, semivolatile metals, and low volatile metals standards. As discussed above, hydrochloric acid production furnaces use wet scrubbers to remove hydrochloric acid from combustion gases to produce the hydrochloric acid product and to minimize residual emissions of hydrochloric acid and chlorine gas. Wet scrubbers also remove metal HAP, including mercury, from combustion gases. To minimize contamination of hydrochloric acid product with metals, hydrochloric acid production furnaces generally feed hazardous waste with low levels of metal HAP. Moreover, the wet scrubbers used to recover the hydrochloric acid product and minimize residual emissions of hydrochloric acid and chlorine gas also control emissions of metal HAP to very low levels. Based on emissions testing within the range of normal emissions ( i. e., not compliance test, maximum allowed emissions), hydrochloric acid production furnaces emit mercury at levels from 0.1 to 0.4 ug/ dscm, semivolatile metals at levels from 0.1 to 4.1 ug/ dscm, and low volatile metals at levels from 0.1 to 43 ug/ dscm. 58,59 * OMB Review Draft*

would be not be allowed to operate under these conditions under today's proposed rule: 14 ppmv total chlorine emission limit, or 99.9927 system removal efficiency. Thus, under the proposed rule, emissions of low volatile metals and particulate matter would be substantially lower.

208 We also note that these sources emit low levels of particulate matter. Compliance test, maximum allowable emissions of particulate matter range from 0.001 to 0.013 gr/ dscf. Because wet scrubbers designed to recover the hydrochloric acid product and control residual emissions of hydrogen chloride and chlorine gas also control emissions of mercury, and semivolatile and low volatile metals ( including nonenumerated metals), use of MACT wet scrubbers to comply with the proposed total chlorine standard discussed below will also ensure MACT control of metal HAP. Accordingly, we propose to use the total chlorine standard as a surrogate for the mercury, semivolatile metals, and low volatile metals standards. C. What Is the Rationale for the Proposed Standards for Total Chlorine? The proposed standards for total chlorine are 14 ppmv or 99.9927 percent total chlorine system removal efficiency ( SRE) for existing sources and 1.2 ppmv or 99.99937 percent total chlorine SRE for new sources. A source may elect to comply with either standard. 1. What Is the Rationale for the MACT Floor for Existing Sources? The proposed MACT floor for existing sources is compliance with either a total chlorine emission level of 14 ppmv or a total chlorine SRE of 99.9927 percent. Hydrochloric acid production furnaces use wet scrubbers to remove hydrochloric acid from combustion gases to produce the hydrochloric acid product and to minimize residual emissions of hydrochloric acid and chlorine gas. We have compliance test, maximum allowable total chlorine emissions data for all 17 hydrochloric acid production furnaces. Total chlorine emissions range from 0.4 to 500 ppmv, and total chlorine system removal efficiencies ( SRE) range from 98.967 to 99.9995 percent. As discussed in Section VI. C above, control of the feedrate of chlorine in hazardous waste fed to the furnace is not an appropriate MACT emission control technique because hydrochloric acid production furnaces are designed to produce hydrochloric acid from chlorinated feedstocks. Consequently, the approaches we normally use to identify the best performing sources SRE/ Feed Approach or Emissions Approach are not appropriate because they directly or indirectly consider chlorine feedrate. More simply, limiting feedrate means not producing the intended product, a result inconsistent with MACT. See 2 Legislative History at 3352 ( House Report) (" MACT is not intended to ... drive sources to the brink of shutdown"). To avoid this concern, we identify a floor SRE, and provide an alternative floor as a total chlorine emission limit based on floor SRE and the highest chlorine feedrate for any source in the data base. By using the highest chlorine feedrate to calculate the alternative total chlorine emission limit, we ensure that feedrate control ( i. e. nonproduction of product) is not a factor in identifying the proposed MACT floor. The alternative total chlorine emission limit would require a source that may not be achieving floor SRE to achieve total chlorine emission levels no greater than the level that would be emitted by any source achieving floor SRE. The floor SRE is 99.9927 percent. It is calculated from the five best SREs, and considers * OMB Review Draft*

209 emissions variability. Floor SRE is an SRE that the average of the performing sources could be expected to achieve in 99 of 100 future tests when operating under conditions identical to the compliance test conditions during which the emissions data were obtained. We estimate that this SRE is being achieved by 29% of sources. The alternative floor emission limit is 14 ppmv, and is the emission level that the source with the highest chlorine feedrate 2.9E+ 8 ug/ dscm   would achieve when achieving 99.9927 percent SRE. Approximately 24% of sources are achieving the alternative floor levels, and these floor levels would reduce total chlorine emissions by 145 tons per year. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We evaluated improved design, operation, and maintenance of existing scrubbers to achieve a beyond the floor emission level of 7 ppmv for total chlorine for existing sources, assuming a 50% reduction in emissions from the floor level. The national annualized compliance cost for hydrochloric acid production furnaces to comply with this beyond the floor standard would be $ 0.25 million, and emissions of total chlorine would be reduced by 3 tons per year. The cost effectiveness of this beyond the floor standard would be $ 76,000 per ton of total chlorine removed. We evaluated nonair quality health and environmental impacts and energy effects and determined that this beyond the floor option would increase both the amount of hazardous wastewater generated and water usage by approximately 82 million gallons per year and would increase electricity usage by 0.34 million kW hours per year. Generation of nonwastewater hazardous waste would decrease by 7 tons per year. Considering these impacts and costeffectiveness as well, we conclude that a beyond the floor standard for existing sources would not be warranted. For these reasons, we propose a floor total chlorine standard of 14 ppmv or 99.9927% SRE for existing sources. 3. What Is the Rationale for the MACT Floor for New Sources? The proposed MACT floor for new sources is compliance with either a total chlorine emission level of 1.2 ppmv or a total chlorine SRE of 99.99937 percent. We use the same rationale for identifying alternative floors for new sources as discussed above in the context of existing sources. The new source floor SRE is the SRE that the single best performing source ( i. e, source with the best SRE) could be expected to achieve in 99 of 100 future tests when operating under conditions identical to the compliance test conditions during which the emissions data were obtained. The new source floor alternative emission limit is an emission level that the source with the highest chlorine feedrate 2.9E+ 8 ug/ dscm   would achieve when achieving 99.99937 percent SRE. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources We evaluated a beyond the floor standard for new sources of 0.60 ppmv based on achieving a 50 percent reduction in emissions by improving the design/ operation/ maintenance of the wet scrubber. The incremental annualized cost for a new solid fuel fired boiler with average gas flowrate to meet a beyond the floor level of 0.60 ppmv would be approximately $ 0.15 million * OMB Review Draft*

210 and would provide an incremental reduction in total chlorine emissions of 0.07 tons per year, for a cost effectiveness of $ 2.1 million per ton of total chlorine removed. We evaluated nonair quality health and environmental impacts and energy effects and determined that, for a new source with average gas flowrate, this beyond the floor option would increase both the amount of hazardous wastewater generated and water usage by approximately 26 million gallons per year and would increase electricity usage by 0.25 million kW hours per year. Considering these impacts and cost effectiveness as well, we conclude that a beyond thefloor standard for new sources would not be warranted. For the reasons discussed above, we propose a total chlorine standard of 1.2 ppmv or a total chlorine SRE of 99.99937 percent for new sources. D. What Is the Rationale for the Proposed Standards for Carbon Monoxide or Hydrocarbons? To control emissions of organic HAP, existing and new sources would be required to comply with either a carbon monoxide standard of 100 ppmv or a hydrocarbon standard of 10 ppmv. 1. What Is the Rationale for the MACT Floor for Existing Sources? Hydrochloric acid production furnaces that burn hazardous waste are currently subject to RCRA standards that require compliance with either a carbon monoxide standard of 100 ppmv, or a hydrocarbon standard of 20 ppmv. Compliance is based on an hourly rolling average as measured with a CEMS. See § 266.104( a). All hydrochloric acid production furnaces have elected to comply with the 100 ppmv carbon monoxide standard. We propose floor standards of 100 ppmv for carbon monoxide or 10 ppmv for hydrocarbons for the same reasons discussed above in the context of liquid fuel fired boilers. There would be no incremental emission reductions associated with these floors because sources are currently achieving the carbon monoxide standard.. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources Our considerations for beyond the floor standards for existing hydrochloric acid production furnaces are identical to those discussed above for existing liquid fuel fired boilers. For the reasons discussed above in the context of liquid fuel fired boilers, we conclude that beyond the floor standards for carbon monoxide and hydrocarbons for existing hydrochloric acid production furnaces are not warranted. 3. What Is the Rationale for the MACT Floor for New Sources? MACT floor for new sources would be the same as the floor for existing sources 100 ppmv for carbon monoxide and 10 ppmv for hydrocarbons and based on the same rationale. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources Our considerations for beyond the floor standards for new hydrochloric acid production furnaces are identical to those discussed above for new liquid fuel fired boilers. For the reasons discussed above in the context of liquid fuel fired boilers, we conclude that beyond the floor standards for carbon monoxide and hydrocarbons for new hydrochloric acid production furnaces are not warranted. E. What Is the Rationale for the Proposed Standard for Destruction and Removal Efficiency? To control emissions of organic HAP, existing and new sources would be required to * OMB Review Draft*

211 comply with a destruction and removal efficiency ( DRE) of 99.99% for organic HAP. For sources burning hazardous wastes F020, F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% for organic HAP. 1. What Is the Rationale for the MACT Floor for Existing Sources? Hydrochloric acid production furnaces that burn hazardous waste are currently subject to RCRA DRE standards that require 99.99% destruction of designated principal organic hazardous constituents ( POHCs). For sources that burn hazardous wastes F020, F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% destruction of designated POHCs. See § 266.104( a). The DRE standard helps ensure that a combustor is operating under good combustion practices and thus minimizing emissions of organic HAP. Under the MACT compliance regime, sources would designate POHCs that are organic HAPs or that are surrogates for organic HAPs. We propose to establish the RCRA DRE standard as the floor for existing sources because it is a currently enforceable Federal standard. There would be no incremental emission reductions associated with this floor because sources are currently complying with the standard. 2. EPA's Evaluation of Beyond the Floor Standards for Existing Sources We considered a beyond the floor level for DRE based on use of better combustion practices but conclude that it may not be replicable by the best performing sources nor duplicable by other sources given that we cannot quantify better combustion practices. Moreover, we cannot ensure that a higher DRE standard would significantly reduce emissions of organic HAP given that DRE measures the destruction of organic HAP present in the boiler feed rather than gross emissions of organic HAP. Although a source's combustion practices may be adequate to destroy particular organic HAP in the feed, other organic HAP may be emitted as products of incomplete combustion. For these reasons, and after considering nonair quality health and environmental impacts and energy requirements, we are not proposing a beyond the floor DRE standard for existing sources. 3. What Is the Rationale for the MACT Floor for New Sources? We propose to establish the RCRA DRE standard as the floor for new sources because it is a currently enforceable Federal standard. 4. EPA's Evaluation of Beyond the Floor Standards for New Sources Using the same rationale as we used to consider a beyond the floor DRE standard for existing sources, we conclude that a beyond the floor DRE standard for new sources is not warranted. Consequently, after considering nonair quality health and environmental impacts and energy requirements, we are proposing the floor DRE standard for new sources.

XIII. What Is the Rationale for Proposing Alternative Risk Based Standards for Hydrogen Chloride and Chlorine Gas in Lieu of the MACT Standard for Total Chlorine?

[ Discussion to be inserted after discussions with OAQPS] * OMB Review Draft*

60 Please note that we also propose to revise the existing schedule for the initial comprehensive performance test for incinerators, cement kilns, and lightweight aggregate kilns. Under the proposed revised schedule, owners and operators of incinerators, cement kilns, and lightweight aggregate kilns would be required to conduct the initial comprehensive performance test to document compliance with the replacement standards proposed today ( § § 63.1203A, 63.1204A, and 63.1205A) within 12 months of the compliance date. See discussion in Part Three, Section I. F.

61 For this reason, in the technical support documents for today's proposed rule we also refer extensively to the technical support documents for the Phase I rule.

212 XIV. How Did EPA Determine Testing and Monitoring Requirements for the Proposed Rule? The CAA requires us to develop regulations that include monitoring and testing requirements. CAA section 114 ( a) ( 3). The purpose of these requirements is to allow us to determine whether an affected source is operating in compliance with the rule. We propose testing and monitoring requirements for solid fuel fired boilers, liquid fuelfired boilers and hydrochloric acid production furnaces that are identical to those applicable to incinerators, cement kilns, and lightweight aggregate kilns under § § 63.1207, 63.1208, and 63.120960 Please note, however, that we discuss below a proposed requirement for boilers that would not be subject to a numerical dioxin/ furan emission standard to conduct a one time test for dioxin/ furan emissions. In addition, in Part Three of today's preamble, we request comment on, or propose revisions to, several compliance requirements. Any amendments to the compliance requirements that we promulgate would be applicable to all hazardous waste combustors. In addition, we discuss below in this section proposed compliance procedures for emission standards that would be based on normal rather than compliance test data and that would be applicable to all hazardous waste combustors subject to such a standard. Finally, we discuss below in this section proposed compliance procedures for emission standards based on hazardous waste thermal emissions that would be applicable to all hazardous waste combustors. The rationale for the testing and monitoring requirements, and implementation of the requirements, is the same as discussed in the rulemakings promulgating those requirements for hazardous waste burning incinerators, cement kilns, and lightweight aggregate kilns, and as discussed in Part Three of today's preamble. See 61 FR 43501 ( August 23, 1996), 62 FR 24212 ( May 2, 1997), 67 FR 6791 ( February 13, 2002), and 67 FR 6967 ( February 14, 2002). For this reason, we only summarize those identical requirements and our rationale for them in today's notice. 61 A. What Is the Rationale for the Proposed Testing Requirements? The proposed rule requires solid fuel fired boilers and liquid fuel fired boilers to perform * OMB Review Draft*

62 Those boilers that would be subject to a numerical dioxin/ furan standard ( i. e., liquid fuel fired boilers equipped with an electrostatic precipitator or fabric filter) would be required to conduct periodic comprehensive and confirmatory testing. Other boilers would be required to conduct a one time test for dioxin/ furan emissions under the conditions discussed below in the text.

63 Because the dioxin/ furan confirmatory test is conducted under operating conditions that are within the range of normal operations rather than at the upper end of the range of normal operations as during a comprehensive performance test, you would not reestablish operating conditions for dioxin/ furan based on the confirmatory performance test.

213 an initial comprehensive performance test for dioxin/ furan62, mercury, particulate matter, semivolatile metals, low volatile metals, and total chloride to demonstrate compliance with emission standards. Hydrochloric acid production furnaces would be required to perform an initial comprehensive performance test for dioxin/ furan and total chloride to demonstrate compliance with emission standards. All three source categories are also subject to the destruction and removal efficiency standard. Compliance with the destruction and removal efficiency standard, however, is based on a one time emissions test, and previous destruction and removal efficiency testing under RCRA requirements may be used for that demonstration if design, operation, or maintenance of the source has not changed in a manner that could adversely affect combustion efficiency and, thus, destruction and removal efficiency. Finally, all three source categories would be required to demonstrate compliance with the carbon monoxide/ hydrocarbon emission standard during the comprehensive performance test ( and at all other times). The comprehensive performance test would be conducted every five years to ensure that the performance of the air pollution control device has not deteriorated and that other factors that may affect emissions have not caused an increase in emissions above the standards. The proposed rule also requires confirmatory testing to ensure compliance with the dioxin/ furan emission standards, the test to be conducted mid way between comprehensive performance tests when operating under typical conditions rather than at performance test conditions. More frequent confirmatory testing for dioxin/ furan is needed because dioxin/ furan emissions can be affected by various and interrelated factors, some of which are not fully understood, and because of the particular health hazard posed by emissions of dioxin/ furan. To ensure continuous compliance with the emissions standards, you would be required to establish limits on key operating parameters susceptible to continuous monitoring. The limits would be based on operating values achieved during the comprehensive performance test when the source successfully demonstrates compliance. 63 Because operating limits are calibrated based on operations during the comprehensive performance test, sources generally operate at the upper end of the range of normal operations during these tests. These proposed requirements are discussed below in Section XII. C. B. What Are the Dioxin/ Furan Testing Requirements for Boilers that Would Not Be Subject * OMB Review Draft*

64 Incinerators equipped with waste heat recovery boilers are know to emit high levels of dioxin/ furan, and hydrochloric acid production furnaces with waste heat recovery boilers can also emit high levels of dioxin/ furan. Because the mechanisms that affect formation and control of dioxin/ furan are complex and not fully understood, we are concerned that some of the factors that cause high dioxin/ furan emissions from incinerators and hydrochloric acid production 214 to a Numerical Dioxin/ Furan Emission Standard? As explained earlier, we are not proposing numerical dioxin/ furan emission standards for solid fuel fired boilers and for those liquid fuel fired boilers that are equipped with wet scrubbers or no particulate control device. Rather, those boilers would be subject to the carbon monoxide/ hydrocarbon emission standard and the destruction and removal efficiency standard to help minimize dioxin/ furan emissions. See discussion in Part Two, Sections X. A and XI. A. We propose that solid fuel fired boilers and those liquid fuel fired boilers that would not be subject to a numerical dioxin/ furan emission standard conduct a one time dioxin/ furan emission test to quantify the effectiveness of today's proposed surrogate dioxin/ furan emission controls. This test would be performed no later than the initial comprehensive performance test required under the proposed standards. The results of this one time test would be reported with the test results for the first comprehensive performance test. See proposed § 63.1207( b)( 3). 1. What Is the Rationale for Requiring the Test? We are adopting this provision pursuant to our authority in CAA Section 114 ( a)( 1)( D), which allows EPA to require " any person ... who is subject to any requirement of this chapter" ( which includes Section 112) on a one time, periodic or continuous basis, to " sample such emissions ( in accordance with such procedures or methods, at such locations, at such intervals, during such periods and in such manner as the Administrator shall prescribe)". The purpose of such monitoring is " developing or assisting in the development of" standards under various provisions of the Act, including Section 112. In this case, monitoring will assist in making determinations under both Section 112( d)( 6) and Section 112( f), which could lead to development of standards under either or both of these provisions. Section 112( d)( 6) of the Act requires us to " review, and revise as necessary emission standards promulgated under this section no less than every eight years." We believe testing that results from compliance with today's proposed standards will, in nearly all cases, establish an adequate database for us to perform this review. However, we would not have sufficient dioxin/ furan emissions data for those boilers that are subject to the carbon monoxide/ hydrocarbon standard and destruction and removal efficiency standard in lieu of a numerical dioxin/ furan standard. We have data from approximately one third of the boilers that are not subject to a numerical dioxin/ furan standard. Although those data indicate that these sources emit low concentrations of dioxin/ furan despite the absence of any dioxin/ furan control equipment, we are concerned about extrapolating this performance to the entire universe of the subject boilers because our data set may not be statistically random and the potential hazard posed by dioxin/ furan is high. In fact, the design of these sources would seem to have the potential for formation of significant dioxin/ furan concentrations. 64 We think this proposed testing would add * OMB Review Draft*

furnaces equipped with waste heat recovery boilers may also affect dioxin/ furan emissions from boilers.

65 Lee, C. W.; Kilgroe, J. D.; Raghunathan, K. Environ. Eng. Sci. 1998, 15( 1), 71 84.

66 Gullett, B. K.; Touati, A.; Lee, C. W. Environ. Sci. Technol. 2000, 34, 2069 2074.

215 a one time cost of approximately $ 10,000 for each source for which dioxin/ furan test data are not already available, and the cost appears reasonable to enable us to meet our Section 112( d)( 6) and 112( f) mandates. Section 112 ( d) ( 6) requires EPA, at specified times, to determine if further technology based emission reductions are warranted. Quantified dioxin/ furan emission information from these sources will assist in this determination. Section 112( f) requires EPA ( among other things) to determine if emissions from all sources subject to Section 112( d) standards must be further reduced in order to assure an ample margin of safety to protect public health. Having actual emission data from these sources obviously will assist in making the required Section 112( f) determinations for these sources. 2. What Are the Operating Requirements for the Test? You must perform the dioxin / furan test under feed and operating conditions that are most likely to maximize dioxin/ furan emissions, similar to a dioxin/ furan comprehensive performance test. Based on currently available research, the following factors should be considered for the testing: ( 1) dioxin/ furan testing should be conducted at the point in the maintenance cycle for the boiler when the boiler tubes are more fouled and soot laden, and not after maintenance involving soot or ash removal from the tubes; ( 2) dioxin/ furan testing should be performed following ( or during) a period of feeding normal or greater quantities of metals; ( 3) dioxin/ furan testing should be performed while feeding normal or greater quantities of chlorine; ( 4) the flue gas temperature in some portion of the heat recovery section of the boiler should be within the dioxin formation temperature window of 750 to 400

F during the testing; ( 5) the testing should not be conducted under optimal combustion conditions; ( 6) for units equipped with wet air pollution control systems, the testing should be conducted after a high solids loading has developed in the scrubber system; and ( 7) for solid fuel fired boilers, the sulfur content of the coal should be equivalent to or lower than normal coal sulfur levels, and the gas temperature at the inlet to the electrostatic precipitator or fabric filter should be close to the operating limit. In addition, unless sulfur compounds are routinely fed to the unit, dioxin/ furan testing should not be performed after a period of firing high sulfur fuel or injection of sulfur additives. The majority of these recommendations are based on research demonstrating that soot deposits can enhance dioxin/ furan formation in the presence of chlorine and catalytic metal contaminants, with formation continuing even after cessation of those contaminant feeds to the system. 65,66 The boiler tube deposits serve as a sink and source for dioxin/ furan reactants ( catalytic metals and chlorine), and combined soot copper deposits have been shown to cause * OMB Review Draft*

67 Takaoka, M.; Liao, P.; Takeda, N.; Fujiwara, T.; Oshita, K. Chemosphere 2003, 53, 153 161.

68 Please note that we discuss in Section XIII of the preamble above concerns with the accuracy of M26/ 26A for measuring emissions of total chlorine for cement kilns. As we explain there, although M26/ 26A is appropriate for demonstrating compliance with the MACT 216 more dioxin/ furan formation than a deposit of soot or copper alone. From analysis of soot deposits taken from different sections of a firetube boiler, the highest measured dioxin/ furan concentrations were found in those deposits containing the highest concentrations of copper and chloride. Those same deposits were removed from the boiler passages where flue gas temperatures ranged from 600 300

C, which is within the often cited optimal temperature region for dioxin/ furan formation. Tube deposits have also been shown to have a negative effect on dioxin emissions when those deposits have been affected by sulfur dioxide, which is why dioxin/ furan testing is not recommended following a period of feeding higher than normal levels of sulfur to the boiler. The recommendation not to test under optimal combustion conditions has been explained previously in the September 1999 Final Rule preamble discussion. See 64 FR at 52937. Good combustion practices minimize dioxin/ furan emissions by: ( 1) destroying trace dioxins/ furans that may be present in feed streams; ( 2) minimizing gas phase formation of dioxins/ furans; and ( 3) minimizing dioxin/ furan precursors that may enhance post combustion formation. For units equipped with wet air pollution control systems, it is also recommended that testing be conducted after a high solids loading has developed in the scrubber system. Research conducted to explore the phenomenon of increased dioxin/ furan flue gas concentrations across some wet scrubber systems has shown differing flue gas outlet dioxin/ furan homologue profiles than flue gas inlet profiles to the scrubber, but similar flue gas outlet homologue profiles to scrubber suspended solids and sludge profiles. 67 This result suggests that some type of memory effect may be associated with suspended solids in a scrubber system which can cause higher dioxin/ furans emissions. You may use data in lieu of testing to document dioxin/ furan emissions for similar on site boilers. In addition, dioxin/ furan emission data from previous testing would be acceptable, provided the test was performed in a manner likely to maximize dioxin/ furan emissions. C. What Are the Proposed Test Methods? The proposed emission standards are method based standards, meaning that the stack test methods used for compliance must be the same as those used to generate the emissions data we used to calculate the standards. Because alternative stack methods may report lower emissions, it is appropriate to require use of the same methods for compliance as sources used to generate the emissions data in our data base. For this reason, you would be required to use the following stack test methods for compliance: ( 1) Method 29 for mercury, semivolatile metals, and low volatile metals; and ( 2) Method 26/ 26A for total chlorine. 68 For dioxin/ furan, the rule would require use of Method * OMB Review Draft*

standards for cement kilns, it is not acceptable for demonstrating compliance with risk based standards developed under authority of Section 112( d)( 4) of the Act.

69 Method 0023A, however, is included in " Test Methods for Evaluating Solid Waste, Physical/ Chemical Methods," EPA Publication sw 846 Third Edition ( November 1986), as amended.

70 Except that some parameters are limited based on the recommendations/ specifications of the manufacturer of the control device.

71 If you elect to comply with the carbon monoxide standard rather than the hydrocarbon standard, you would be required to document that hydrocarbon emissions during the comprehensive performance test meet the standard.

217 0023A unless you receive approval to use Method 23. We discuss the rationale for allowing sitespecific approvals to use Method 23 in Part Three, Section II. D of today's preamble. In addition, for particulate matter, you would be required to use either Method 5, the method used to generate the data in our data base or Method 5i. We allow use of Method 5i because it is more precise than Method 5 at lower particulate matter loadings. These test methods are codified in 40 CFR Part 60, Appendix A. 69 D. What Is the Rationale for the Proposed Continuous Monitoring Requirements? The most direct means of ensuring compliance with emissions limits is the use of continuous emission monitoring systems ( CEMS). We consider other options when CEMS are not available or when we consider the impacts of including such requirements unreasonable. When monitoring options other than CEMS are considered, it is often necessary for us to balance more reasonable costs against the quality or accuracy of the emissions monitoring data. Although monitoring operating parameters cannot provide a direct measurement of emissions, it is often a suitable substitute for CEMS. The information provided can be used to ensure that air pollution control equipment is operating properly. Because most parameter requirements are calibrated during comprehensive performance testing, 70 they provide a reasonable surrogate for direct monitoring of emissions. This information reasonably assures the public that the reductions envisioned by the proposed rule are being achieved. 1. What CEMS Requirements Did EPA Consider? To comply with the carbon monoxide or hydrocarbon emission limits, you would be required to use a carbon monoxide or hydrocarbon CEMS as well as an oxygen CEMS to correct the carbon monoxide or hydrocarbon values to 7% oxygen. See § 63.1209( a). Because boilers and hydrochloric acid production furnaces are currently required to use these CEMS to comply with existing RCRA emission standards for carbon monoxide or hydrocarbons, there would be a minimal incremental compliance cost. 71 We also evaluated the cost of applying hydrogen chloride CEMS to boilers and hydrochloric acid production furnaces. We estimate the capital costs for hydrogen chloride * OMB Review Draft*

218 CEMS to be $ 88,000 per unit and annualized costs to be $ 33,000 per unit. We determined these costs would be unreasonably high considering: ( 1) the CEMS detects hydrogen chloride but not chlorine gas, so that compliance with the total chlorine emission standard could not be monitored; ( 2) the effectiveness of operating parameter limits to ensure compliance with the emission standard for total chlorine; and ( 3) the relatively low level of hazard posed by emissions of total chlorine. Finally, we conclude that toxic metals are not directly measurable with CEMS, and that CEMS for particulate matter have not been demonstrated in the United States for the purpose of determining compliance. 2. What Operating Parameter Limits Would Be Required? To ensure continuous compliance with the proposed emission limits, you would be required to establish limits on key operating parameters and continuously monitor the parameters including: feedrate of metals, chlorine, and, for some source categories, ash; key combustor operating parameters; and key operating parameters of the control device. See § 63.1209( j o). You would also be required to document monitoring by recordkeeping and reporting. We selected the following requirements based on reasonable cost, ease of execution, and usefulness of the resulting data to both owners and operators and EPA for ensuring continuous compliance with the emission limits. To ensure continuous compliance with the dioxin/ furan emission limit, you would be required to establish: ( 1) a limit on maximum gas temperature at the inlet to a dry particulate matter control device; ( 2) a limit on minimum combustion chamber temperature; ( 3) a limit on maximum flue gas flowrate or production rate; ( 4) a limit on maximum waste feedrate; ( 5) if your combustor is equipped with an activated carbon injection system: limits on the particulate matter control device, as discussed below; a limit on minimum carbon injection rate; a limit on minimum carrier fluid flowrate or pressure drop; and you must specify and use the brand ( i. e., manufacturer) and type of carbon used during the comprehensive performance test, unless you document key parameters that affect adsorption and establish limits on those parameters based on the carbon used in the comprehensive performance test; ( 6) if your combustor is equipped with a carbon bed: you must monitor the bed life to ensure that it has not reached the end of its useful life to minimize dioxin/ furan ( and mercury) emissions at least to the levels required by the emission standards; you must replace the bed or bed segment before it has reached the end of its useful life; you must specify and use the brand ( i. e., manufacturer) and type of carbon used during the comprehensive performance test, unless you document key parameters that affect adsorption and establish limits on those parameters based on the carbon used in the comprehensive performance test; and you must establish a limit on maximum gas temperature either at the bed inlet or outlet; ( 7) if your combustor is equipped with a catalytic oxidizer: limits on minimum and maximum gas temperature at the inlet to the catalyst; you must replace the oxidizer when it has reached the maximum service time specified by the manufacturer; and when replacing the catalyst, the new catalyst must be equivalent to or better than the one used during the previous comprehensive performance test as measured by catalytic metal loading for each metal, space time, and substrate construction; ( 8) if you feed a dioxin/ furan inhibitor into the combustion system: a limit on minimum inhibitor feedrate; and you must specify and use the brand ( i. e., * OMB Review Draft*

72 This is because the mercury emission standard for liquid fuel fired boilers is a hazardous waste thermal emission concentration. Liquid fuel fired boilers would also be required to monitor the heating value of hazardous waste feeds to ensure compliance with the hazardous waste thermal emission concentration.

73 The mercury feedrate limit would be based on levels fed during the comprehensive performance test unless the regulatory authority approves a request for you to extrapolate to a higher allowable feedrate ( and emission rate) limit.

219 manufacturer) and type of inhibitor used during the comprehensive performance test, unless you document key parameters that affect the effectiveness of the inhibitor and establish limits on those parameters based on the inhibitor used in the comprehensive performance test. See § 63.1209( k). To ensure continuous compliance with the mercury emission limit, owners and operators of boilers would be required to establish: ( 1) a limit on the total feedrate of mercury in all feedstreams for solid fuel fired boilers, and a limit on mercury in hazardous waste feedstreams per million Btu of hazardous waste fired for liquid fuel fired boilers; 72,73 ( 2) if your boiler is equipped with a wet scrubber, limits prescribed for control of total chlorine with a wet scrubber, except for a limit on minimum pH of the scrubber water; ( 3) if your boiler is equipped with an activated carbon injection system, limits on the particulate matter control device as discussed below, and limits on the activated carbon injection system as discussed above for dioxin/ furan; and ( 4) if your boiler is equipped with an activated carbon bed, limits on the carbon bed as discussed above for dioxin/ furan. You may comply with mercury feedrate limits only, however, if you elect to assume that all mercury in the feed is emitted. For solid fuel fired boilers, you would assume that all mercury in all feedstreams is emitted under this alternative approach. For liquid fuel fired boilers where the mercury emission standard is expressed as hazardous waste thermal emissions, you would assume that all mercury in all hazardous waste feedstreams is emitted. Under this alternative compliance approach, you would also establish a limit on minimum flue gas flowrate to ensure compliance with the mercury emission standard. Also, please note that these compliance requirements would not apply to hydrochloric acid production furnaces, , because ( as explained earlier) we propose to use the total chlorine standard as a surrogate for the mercury, particulate matter, semivolatile metal, and low volatile metal standards for these sources. See § 63.1209( l). To ensure continuous compliance with the particulate matter emission limit, you would be required to establish: ( 1) limits on the control device operating parameters; ( 2) a limit on maximum flue gas flowrate or production rate; and a limit on maximum ash feedrate. If your boiler is equipped with a wet scrubber, you would establish limits on: ( 1) for high energy scrubbers only, minimum pressure drop across the scrubber and either minimum liquid to gas ratio or minimum scrubber water flowrate and maximum flue gas flowrate; and ( 2) for all scrubbers, the solids content of the scrubber liquid or a minimum blowdown rate. If your boiler is equipped with an electrostatic precipitator, ionizing wet scrubber, or fabric filter, please note that we discuss in Part Three, Section II. I. below proposed compliance parameters for these control devices. Briefly, if your boiler is equipped with a fabric filter, you must comply with bag leak detection * OMB Review Draft*

74 This is because the semivolatile metal and low volatile metal emission standards for liquid fuel fired boilers are hazardous waste thermal emission concentrations. You would also be required to monitor the heating value of hazardous waste feedstreams to ensure compliance with the hazardous waste thermal emission concentration.

75 The semivolatile and low volatile metal feedrate limits would be based on levels fed during the comprehensive performance test unless the regulatory authority approves a request for you to extrapolate to higher allowable feedrate ( and emission rate) limits. Please note that the semivolatile and low volatile metal feed limits for liquid fuel fired boilers are hazardous waste thermal concentration limits ( pounds of metal per million Btu), not mass feedrate limits, given that the emission standards are expressed as hazardous waste thermal emissions.

220 system requirements. If your boiler is equipped with an electrostatic precipitator or ionizing wet scrubber, you must either: ( 1) install and operate a particulate matter loading detector as a process monitor to indicate when you must take corrective measures; or ( 2) establish limits on key operating parameters, on a site specific basis, that are representative and reliable indicators that the control device is operating within the same range of conditions as during the comprehensive performance test, and link those operating limits to the automatic waste feed cutoff system. Please note that the particulate matter compliance requirements would not apply to hydrochloric acid production furnaces, as discussed above. See § 63.1209( m). To ensure continuous compliance with the semivolatile and low volatile metal emission limits, you would be required to establish: ( 1) a limit on the maximum inlet temperature to the primary dry particulate matter control device; ( 2) a limit on maximum feedrate of semivolatile and low volatile metals from all feedstreams for solid fuel fired boilers, and a limit on semivolatile metals and low volatile metals in hazardous waste feedstreams per million Btu of hazardous waste fired for liquid fuel fired boilers; 74,75; ( 3) limits ( or process monitors) on the particulate matter control device as discussed above; ( 4) a limit on maximum feedrate of total chlorine or chloride in all feedstreams; and ( 5) a limit on maximum flue gas flowrate or production rate. You may comply with semivolatile and low volatile metal feedrate limits only, however, if you elect to assume that all semivolatile and low volatile metals in the feed is emitted. For solid fuel fired boilers, you would assume that all semivolatile and low volatile metals in all feedstreams are emitted under this alternative approach. For liquid fuel fired boilers where the semivolatile and low volatile metals emission standards are expressed as hazardous waste thermal emissions, you would assume that all semivolatile and low volatile metals in all hazardous waste feedstreams are emitted. Under this alternative compliance approach, you would also establish a limit on minimum flue gas flowrate to ensure compliance with the semivolatile and low volatile metal emission standards. Also, please note that the semivolatile metal and low volatile metal compliance requirements would not apply to hydrochloric acid production furnaces, as discussed above. See § 63.1209( n). To ensure continuous compliance with the total chlorine emission limit, you would be required to establish: ( 1) a limit on maximum feedrate of total chlorine and chloride from all * OMB Review Draft*

76 This is because the total chlorine emission standard for liquid fuel fired boilers is a hazardous waste thermal emission concentration. You would also be required to monitor the heating value of hazardous waste feedstreams to ensure compliance with the hazardous waste thermal emission standard.

221 feedstreams for solid fuel fired boilers, and a limit on total chlorine and chloride in hazardous waste feedstreams per million Btu of hazardous waste fired for liquid fuel fired boilers; 76 ( 2) a limit on maximum flue gas flowrate or production rate; ( 3) if your combustor is equipped with a high or low energy wet scrubber: a limit on minimum pH of the scrubber water; a limit on either the minimum liquid to gas ratio or the minimum scrubber water flowrate and maximum flue gas flowrate; ( 4) if your combustor is equipped with a high energy wet scrubber, a limit on minimum pressure drop across the scrubber; ( 5) if your combustor is equipped with a low energy wet scrubber: a limit on minimum pressure drop across the scrubber; and a limit on minimum liquid feed pressure to the scrubber; and ( 6) if your combustor is equipped with a dry scrubber: a limit on minimum sorbent feedrate; a limit on minimum carrier fluid flowrate or nozzle pressure drop; and you must specify and use the brand ( i. e., manufacturer) and type of sorbent used during the comprehensive performance test, unless you document key parameters that affect the effectiveness of the sorbent and establish limits on those parameters based on the sorbent used in the comprehensive performance test. If your combustor is equipped with an ionizing wet scrubber, please note that we discuss in Part Three, Section II. I. below proposed compliance parameters for this control device. Briefly, if your combustor is equipped with an ionizing wet scrubber, you must either: ( 1) install and operate a particulate matter loading detector as a process monitor to indicate when you must take corrective measures; or ( 2) establish limits on key operating parameters, on a site specific basis, that are representative and reliable indicators that the control device is operating within the same range of conditions as during the comprehensive performance test, and link those operating limits to the automatic waste feed cutoff system. You may comply with a total chlorine and chloride feedrate limit only, however, if you elect to assume that all chlorine in the feed is emitted. For solid fuel fired boilers, you would assume that all chlorine in all feedstreams is emitted under this alternative approach. For liquid fuel fired boilers where the total chlorine emission standard is expressed as hazardous waste thermal emissions, you would assume that all chlorine in all hazardous waste feedstreams is emitted. Under this alternative compliance approach, you would also establish a limit on minimum flue gas flowrate to ensure compliance with the total chlorine standard. See § 63.1209( o). To ensure continuous compliance with the destruction and removal efficiency standard, you would be required to: ( 1) establish a limit on minimum combustion chamber temperature; ( 2) establish a limit on maximum flue gas flowrate or production rate; ( 3) establish a limit on maximum hazardous waste feedrate; and ( 4) specify operating parameters and limits to ensure that good operation of each hazardous waste firing system is maintained. See § 63.1209( j). E. What Are the Averaging Periods for the Operating Parameter Limits, and How Are Performance Test Data Averaged to Calculate the Limits? Except as discussed in Section XIV. F below, we propose that owners and operators of * OMB Review Draft*

77 Please note, however, that we request comment on the appropriateness of these combustion system leak requirements in Part Three of today's preamble.

78 Manual method emission test results for each run represent average emissions over the entire run.

222 solid fuel fired boilers, liquid fuel fired boilers, and hydrochloric acid production furnaces establish averaging periods for the operating parameter limits and calculate the limits from comprehensive performance test data under the same approaches required currently for incinerators, cement kilns, and lightweight aggregate kilns. A detailed discussion of how those approaches work, and the rationale for them, are provided at 64 FR at 52919 22 ( September 30, 1999). That discussion is summarized below. We propose the following averaging periods: ( 1) no averaging period ( i. e., instantaneous monitoring) for maximum combustion chamber pressure to control combustion system leaks77; ( 2) 12 hour rolling averages for maximum feedrate of mercury, semivolatile metals, low volatile metals, total chlorine and chloride, and ash; and ( 3) one hour rolling averages for all other operating parameters. We propose a 12 hour rolling average for metal, total chlorine and chloride, and ash feedrate limits to correspond to the potential duration of three runs of a comprehensive performance test, considering that feedrate and emissions, are, for the most part, linearly related. We propose an hourly rolling average limit for all parameters that are based on operating data from the comprehensive performance test, except combustion chamber pressure and metal, chlorine, and ash feedrate limits. Hourly rolling averages are appropriate for these parameters rather than averaging periods based on the duration of the performance test because we are concerned that there may be a nonlinear relationship between operating parameter levels and emission levels of HAP or HAP surrogates. We propose two approaches to calculate limits for operating parameters: ( 1) calculate the limit as the average of the maximum ( or minimum, as specified) rolling averages for each run of the test; or ( 2) calculate the limit as the average of the test run averages for each run of the test. Hourly rolling averages for two parameters combustion gas flowrate or production rate and hazardous waste feedrate would be based on the average of the maximum hourly rolling averages for each run. Hourly rolling average and 12 hour rolling average limits for all other parameters, however, would be based on the average level occurring during the comprehensive performance test. We conclude that this more conservative approach is appropriate for these parameters because they can have a greater effect on emissions, and because it is consistent with how manual emissions results are determined. 78 We also conclude that limits based on the average level occurring during the comprehensive performance are readily achievable. This is because sources generally conduct performance testing at the extreme upper end of the range of normal operations to provide the operating flexibility needed after establishing operating parameter limits. Because sources can readily control ( during the performance test and thereafter) the parameters for which limits are established, the operating limits based on the average of the performance test runs should be readily achievable under routine operations. * OMB Review Draft*

79 These are maximum emissions because operating parameter limits for the HAP or HAP surrogate are established based on this compliance test.

223 F. How Would Sources Comply with Emissions Standards Based on Normal Emissions? Several proposed emission standards would be based on emissions that are within the normal range of operations for the source rather than on compliance test emissions that represent the extreme upper end of the range of normal emissions: 79 mercury standards for cement kilns, lightweight aggregate kilns, and liquid fuel fired boilers, and semivolatile metal emissions for liquid fuel fired boilers. To ensure compliance with emission standards based on normal emissions data, you would document during the comprehensive performance test a system removal efficiency for the metals and back calculate from the emission standard a maximum metal feedrate limit that must not be exceeded on an annual rolling average. If your source is not equipped with an emission control system ( such as activated carbon to control mercury) for the metals in question, however, you must assume zero system removal efficiency. This is because a source that is not equipped with an emission control system may be able to document a positive system removal efficiency, but it is not likely to be reproducible. It is likely to be an artifact of the calculation of emissions and feeds rather than a removal efficiency that is reliable and reproducible. To ensure that you can calculate a valid, reproducible system removal efficiency for sources equipped with a control system that effectively controls the metal in question, you may need to spike metals in the feed during the comprehensive performance test at levels that may result in emissions that are higher than the standard. This would be acceptable because compliance with an emission standard derived from normal emissions data is based on compliance with an annual average feedrate limit calculated as prescribed here, rather than compliance with the emission standard during the comprehensive performance test. We propose a one year averaging period for the metal feedrate limit because the emission standard represents normal, average emissions. Although the averaging period could be substantially shorter or longer, a one year averaging period is within the range of reasonable averaging periods and would be readily achievable for a standard based on normal emissions. The annual rolling average metal feedrate would be updated each hour based on the average of the 60 previous 1 minute averages. We propose to retain the hourly rolling average requirement for the other operating parameter limits, however, for the reasons discussed above ( i. e., to be conservative given the nonlinear relationship between the operating parameter and emissions, and because the limits would be readily achievable). G. How Would Sources Comply with Emission Standards Expressed as Hazardous Waste Thermal Emissions? Several proposed emission standards would be expressed as hazardous waste thermal emissions: mass of pollutant emissions attributable to the hazardous waste feed per million Btu of hazardous waste fed to the combustor. To demonstrate compliance with a hazardous waste thermal emissions based standard * OMB Review Draft*

80 If the hazardous waste thermal emission standard is derived from normal rather than compliance test emissions data, however, the hazardous waste thermal feed concentration would be calculated as discussed above in Section F of the preamble.

224 during a comprehensive performance test, you would calculate the hazardous waste thermal emissions by apportioning mass emissions of mercury, semivolatile metals, low volatile metals, or total chlorine according to the ratio of the mass feedrate of mercury, semivolatile metals, low volatile metals, or total chlorine and chloride from hazardous waste feedstreams to the feedrate for all feedstreams and dividing by the heat input rate ( i. e., million Btu/ hr) attributable to the hazardous waste. To ensure continuous compliance with the hazardous waste thermal emissions based standard, you would calculate an operating limit based on the hazardous waste thermal feed concentration during the performance test. 80 The hazardous waste thermal feed concentration limit would be calculated as the mass feedrate ( lb/ hr) of mercury, semivolatile metals, low volatile metals, or total chlorine and chloride from hazardous waste feedstreams divided by the heat input rate ( million Btu/ hr) from hazardous waste feedstreams. For compliance, you would continuously monitor the feedrate of hazardous waste on a 12 hour rolling average updated each minute or, for standards based on normal emissions, on a annual rolling average updated each hour. You must know the concentration of mercury, semivolatile metals, low volatile metals, or total chlorine and chloride in the hazardous waste at all times, and the heating value of the hazardous waste at all times. Using this information, you would calculate and record the hazardous waste thermal feed concentration on a 12 hour rolling average, or for standards based on normal emissions, on a annual rolling average updated each hour. H. What Are the Other Proposed Compliance Requirements? We propose other compliance requirements for solid fuel fired boilers, liquid fuel fired boilers, and hydrochloric acid production furnaces that are the same as those currently in place at § 63.1206 for incinerators, cement kilns, and lightweight aggregate kilns. The rationale for the requirements is the same as discussed in previous rulemakings for incinerators, cement kilns, and lightweight aggregate kilns, and compliance procedures would be the same as currently required for those sources. The other compliance requirements include provisions for: startup, shutdown, and malfunction plans; operation and maintenance plans including a requirement for bag leak detector systems for fabric filters; automatic hazardous waste feed cutoff systems, including a requirement for exceedance reporting; combustion system leak requirements; changes in design, operation, or maintenance that could adversely affect compliance with emission standards; operator training and certification requirements; and requirements for sources that elect to comply with the carbon monoxide standard to document one time that hydrocarbons also meet the hydrocarbon standard; and provisions allowing a one time demonstration of compliance with the destruction and removal efficiency standard. Please note that we propose revisions to, or request comment on, some of these compliance requirements in Part Three of the preamble. Any revisions to these requirements that * OMB Review Draft*

81 Please note that a new or reconstructed unit for purposes of complying with the Interim Standards applicable to incinerators, cement kilns, and lightweight aggregate kilns is a unit that began operation after September 30, 1999.

225 we might make in the final rule would be applicable to all hazardous waste combustors.

XV. How Did EPA Determine Compliance Times for this Proposed Rule? Section 112 of the CAA specifies the dates by which affected sources must comply with the emission standards. New or reconstructed units must be in compliance with the proposed rule immediately upon startup or [ DATE THE FINAL RULE IS PUBLISHED IN THE FEDERAL REGISTER], whichever is later. A new or reconstructed unit for purposes of complying with this proposed rule is one that begins construction after [ DATE THE PROPOSED RULE IS PUBLISHED IN THE FEDERAL REGISTER]. 81 Existing sources are allowed up to three years to comply with the final rule. See proposed § 63.1206( a)( 1)( ii) and ( a)( 2). This is the maximum period allowed by the CAA. We believe that three years for compliance is necessary to allow adequate time to design, install, and test control systems that will be retrofitted onto existing units.

XVI. How Did EPA Determine the Required Records and Reports for the Proposed Rule? We propose notification, reporting, and recordkeeping requirements for solid fuel fired boilers, liquid fuel fired boilers and hydrochloric acid production furnaces that are identical to those already in place at § § 63.1210 and 63.1211 and applicable to incinerators, cement kilns, and lightweight aggregate kilns. Please note, however, that we are proposing a new requirement applicable to all hazardous waste combustors that would require you to submit a Notification of Intent to Comply and a Compliance Progress Report. A. Summary of Requirements Currently Applicable to Incinerators, Cement Kilns, and Lightweight Aggregate Kilns and that Would Be Applicable to Boilers and Hydrochloric Acid Production Furnaces Owners and operators of solid fuel fired boilers, liquid fuel fired boilers, and hydrochloric acid production furnaces would be required to submit the following notifications to the Administrator in addition to those required by the NESHAP General Provisions, subpart A of 40 CFR part 63: ( 1) notification of changes in design, operation, or maintenance ( § 63.1206( b)( 5)( i)); ( 2) notification of performance test and continuous monitoring system evaluation, including the performance test plan and continuous monitoring system performance evaluation plan ( § § 63.1207( e)); and ( 3) notification of compliance, including results of performance tests and continuous monitoring system evaluations ( § § 63.1210( b), 63.1207( j); 63.1207( k), and 63.1207( l)). You would also be required to submit notifications to the Administrator if you request or elect to comply with various alternative requirements. Those notifications are listed at § 63.1210( a)( 2). Owners and operators of solid fuel fired boilers, liquid fuel fired boilers, and hydrochloric acid production furnaces would be required to submit the following reports to the Administrator * OMB Review Draft*

226 in addition to those required by the NESHAP General Provisions, Subpart A of 40 CFR Part 63: ( 1) startup, shutdown, and malfunction plan ( if electing to comply with § 63.1206( c)( 2)( ii)( B)); ( 2) excessive exceedances report ( § 63.1206( c)( 3)( vi)); and ( 3) emergency safety vent opening reports ( § 63.1206( c)( 4)( iv)). Owners and operators of solid fuel fired boilers, liquid fuel fired boilers, and hydrochloric acid production furnaces would be required to keep records documenting compliance with the requirements of Subpart EEE. Recordkeeping requirements are prescribed in § 63.1211( b), and include requirements under the NESHAP General Provisions, subpart A of 40 CFR Part 63. B. Why Is EPA Proposing Notification of Intent to Comply and Compliance Progress Report Requirements? 1. What Is the Notification of Intent to Comply? In the June 1998 " fast track" rule ( 63 FR 33782), we required that sources subject to the Phase I Subpart EEE standards complete a Notification of Intent to Comply ( NIC) no later than October 2, 2000 and conduct a NIC public meeting no later than July 31, 2000. The NIC and its associated public meeting served four primary purposes during the early implementation and compliance phases of the Phase I Subpart EEE requirements which we believe were of benefit to regulators, sources and the public alike. First, the NIC served as a compliance planning tool for Phase I sources because it required you to develop an outline of the key activities that needed to be completed in order to meet the Subpart EEE standards by the compliance date. It also required that you include the estimated dates for each of those key activities. Because the NIC was required to be completed within the first year of implementing the Phase I requirements, it also may have had the added and important benefit of encouraging sources to reduce their HAP emissions early. By focusing a source's attention on the means by which it would achieve compliance well before the actual compliance date, the NIC may have prompted some sources to upgrade their combustion design and operations earlier, thereby yielding an early reduction in HAP emissions. The NIC also may have prompted earlier waste minimization efforts for the same reason. Second, the NIC also served as a planning tool for regulatory authorities. Based on the information provided in the NIC, regulators could determine what activities were likely to occur and when over the course of the three year compliance period. For example, they could estimate how many sources needed to modify their combustion units and existing RCRA permits prior to performance testing, how many sources intended to stop burning hazardous waste, and how many sources intended to apply for the comparable fuels exclusion. Using this information, regulators could plan how to most efficiently allocate their resources in response to the forthcoming compliance activities of the sources. Third, the NIC promoted early public involvement by fostering an open dialogue between sources and the public regarding compliance strategies for meeting the Phase I Subpart EEE standards. Experience has shown that members of the public are interested in being kept adequately informed of and having input into the compliance and permitting activities of hazardous waste combustion facilities. The NIC and its associated public meeting provided an opportunity for the public to share their views, thereby allowing the source to develop a final compliance strategy that met the goals of both the source and the surrounding community. * OMB Review Draft*

82 Under the Early Cessation provision, we required sources that did not intend to comply with the Phase I standards to stop burning hazardous waste within two years of the effective date of the Phase I rule. Under the Compliance Progress Report provision, we required sources to report to their regulatory agencies the status of their progress toward compliance with the standards.

227 Fourth, the public involvement aspect of the NIC also offset any public participation opportunities that may have been " lost" if sources chose to take advantage of the RCRA streamlined permit modification process. Many Phase I sources had to modify their combustion systems' design and/ or operations in order to comply with the MACT standards. Sources that were already operating under RCRA combustion permits needed to first modify those permits before initiating any MACT compliance related changes. Normally, a Class 2 or 3 modification would be necessary to incorporate into a RCRA permit the types of changes we expected would be necessary for sources complying with Phase I standards. Given that Class 2 and 3 modifications could have consumed a year or more of a source's three year Subpart EEE compliance period, we developed a streamlined permit modification process solely for the purpose of implementing Subpart EEE upgrades. Under the streamlined process, you could request a Class 1 modification with prior Agency approval to address and incorporate any necessary MACT upgrades into your RCRA permit. To be eligible to use the streamlined permit modification, however, you first must have complied with the NIC requirements, including those related to public involvement. 2. What Happened to the NIC Provisions? We promulgated the NIC on June 19, 1998 ( 63 FR 33782) along with several other requirements related to the Phase I NESHAP. On May 14, 2001, we removed the NIC and two other provisions from the federal regulations in response to a court mandate to vacate. See 66 FR 24270. In Chemical Manufacturers Ass'n v EPA, 217 F. 3d 861 ( D. C. Cir. 2000), the court vacated three provisions of the Phase I rule: the Early Cessation requirement, the NIC and the Compliance Progress Report. 82 While the panel majority held that we possessed the legal authority to impose an Early Cessation requirement, the panel also held that we had claimed the authority to do so without making a showing of a health and environmental benefit ( such as reduced HAP emissions or less hazardous waste generated) and that this was an impermissible statutory interpretation. See 217 F. 3d at 865 67. The panel majority further held that because it could not determine whether we would have promulgated the NIC and Progress Report requirements absent the Early Cessation provision, both the NIC and Progress Report requirements should be vacated as well. However, the panel did agree to issue a stay of its mandate for a long enough period of time to allow sources to submit their NICs so that they would be eligible for the RCRA streamlined permit modification. As discussed above, the NIC was intended to serve as a compliance planning and communication tool. We did not intend the NIC to serve as the basis for requiring a source to cease burning hazardous waste. However, as a planning and communication tool we expected sources that did not intend to comply with the standards to state this in their NIC and include a * OMB Review Draft*

83 If a major title V source has a remaining permit term of three or more years on the date the Replacement standards are promulgated, the title V permitting authority must complete a reopening of the source's title V permit to incorporate the requirements of these standards not later than 18 months after promulgation. Major sources having remaining permit terms of less than three years on the date the Replacement standards are promulgated may wait until permit renewal to incorporate the new standards. Area sources with title V permits likewise may wait 228 schedule of activities that the source would need to complete in order to stop burning hazardous waste within the two year Early Cessation time frame. We believe that the court recognized this interpretation as our original intent in their agreement to stay their issuance of the mandate until after sources had submitted their final NICs on October 1, 2000. By allowing the Phase I sources to complete the NIC process, the court provided sources with the opportunity to effectively plan their compliance strategies and take advantage of the RCRA streamlined permit modification. It also provided the public with the opportunity for a level of participation that they may not have had otherwise. 3. Why Is EPA Proposing to Re Institute the NIC for Phase I Sources? As stated above, we believe that the NIC was a valuable planning and communication tool for sources, regulators, and the public during the early implementation and compliance stages of the 1999 Phase I Subpart EEE requirements. The NIC also provided an additional benefit to sources upgrading their combustion systems by compensating for any " lost" public participation opportunities when using the RCRA streamlined permit modification process. As discussed in Part One, I. B and D, we are proposing in today's notice to supplant the existing Phase I standards with final Replacement standards. We anticipate that a significant number of Phase I sources may need to conduct additional upgrades, or in some cases upgrade for the first time, to comply with the Replacements standards. See § § 63.1203A, 63.1204A, and 63.1205A. Reinstituting the NIC for these sources could provide the same planning and communication benefits during the initial Replacement standards compliance period that it did for the original Phase I standards. Specifically, we expect that by focusing attention early on the necessary tasks and strategies for achieving compliance, Phase I sources will be in a better position to meet the Replacement standards by the compliance date. Regulators will gain insight from the information provided in the NIC to effectively allocate their resources to accommodate future regulatory activities. And, the NIC will provide the public with the opportunity and mechanism to keep abreast of any significant changes an existing source might need to make as a result of the Replacement standards. We do not believe that the same planning and communication opportunities gained from completing the NIC process are available from other portions of the air regulatory program. For example, although the public will be notified of a source's obligation to comply with the Replacement standards during the reopening or renewal of the source's title V, this notification, in most cases, will not occur as early in the three year Subpart EEE compliance period, nor is it likely to include the specific information regarding the source's compliance strategy. 83 * OMB Review Draft*

until permit renewal. Permitting authorities must follow the same public notice procedures for title V permit reopenings and renewals as is required for initial permit issuance under title V, including providing public notice of the action, providing a public comment period of at least 30 days, and providing an opportunity for a public hearing. See 40 CFR § § 70.7 and 71.7.

84 Once a source conducts its CPT and submits an Notification of compliance documenting compliance with the Subpart EEE standards, the source may request that its RCRA permit be modified to remove any duplicative limits or conditions. Only those risk based provisions that are more stringent than the MACT requirements as specified in the Notification of compliance or that address other emission hazards will remain in the RCRA permit. We expect that many sources will document compliance with the Phase I Interim standards between 2003 and 2004 and will request the removal of any duplicative, less stringent provisions from their RCRA permits shortly thereafter.

229 In addition, while we believe that there will be fewer Phase I sources in the position of having RCRA combustion permit conditions after demonstrating compliance with the Interim standards, for those that do and wish to use the streamlined permit modification process to allow any necessary Replacement standards upgrades, a second NIC would provide the same public participation benefits as did the first NIC. 84 40 CFR 270.42( j) currently allows a source to use the RCRA streamlined modification process provided that the source first complied with the NIC requirements that were in place prior to October 11, 2000. Since many sources complied with those NIC requirements in 1999 and 2000, the existing regulatory language would allow those same sources to further modify their RCRA permits for Replacement standards upgrades. The regulatory language does not make any distinction regarding when the upgrades are to take place in relation to when the NIC requirements were to have been fulfilled. We do not believe that it is appropriate for a source to rely on previous informational and public participation activities carried out to comply with the earlier NIC requirements and emission standards to address upgrades occurring years later in response to a different set of standards any more than it would be appropriate to allow the public participation activities of a previous RCRA modification to suffice for a later modification. By requiring sources that choose to use the RCRA streamlined permit modification process for Replacement standards upgrades to first complete a NIC, including its associated public meeting, that specifically addresses those Replacement standards upgrades, the community will be kept better informed of additional changes to the combustion system and the impact on the RCRA permit. 4. Why Is EPA Proposing to Require the NIC for Phase II Sources? We believe that the NIC would provide the same benefits with respect to communication and compliance strategy planning for the Phase II sources that it has for Phase I sources. In addition, without completing the NIC process, Phase II sources will not be eligible to take advantage of the RCRA streamlined permit modification when upgrading their combustion systems. We are proposing that Phase II sources comply with the same NIC requirements as their Phase I counterparts. * OMB Review Draft*

230 5. How Will the NIC Process Work? We are proposing to apply a similar NIC process to that which we promulgated in the June 19, 1998 " fast track" rule ( 63 FR 33782). The following is a general description of that process. Within nine months of the promulgation of the final Phase I Replacement standards and Phase II standards, you would develop and make publically available a draft NIC. The draft NIC would contain general information such as whether you are a major or an area source and what waste minimization, emission control techniques, and emission monitoring techniques you might be considering. At the same time, you would also provide a notice to the public of at least one informal NIC public meeting. Within ten months, you would hold this public meeting to discuss the activities you described in the draft NIC for achieving compliance with the Subpart EEE standards. The meeting provides an opportunity for a mutual understanding between you and the public regarding compliance options, including consideration of both technical ( e. g., equipment changes to upgrade air pollution control devices) and operational ( e. g., process changes to minimize waste generation) alternatives. We expect the exchange between you and the community at the meeting to be similar to that which would occur at RCRA pre application meetings. That is, we intend for the meeting to provide an open, flexible and informal occasion for you and the public to discuss various aspects of your compliance strategy, provide an opportunity for sharing ideas and provide an opportunity for building a framework for a solid and positive working relationship. Lastly, you would submit a final NIC to your regulatory authority that would include the information provided in the draft NIC ( revised as necessary after the public meeting) as well as a summary of the public meeting. This final NIC would be submitted to your regulatory authority within one year of the promulgation of the final Phase I Replacement standards and Phase II standards. In summary, we believe that the NIC would provide important planning and communication opportunities for both Phase I and Phase II sources. It also would allow all Phase I, as needed, and Phase II sources to take advantage of the RCRA streamlined permit modification procedure. Thus, we are proposing NIC requirements for both Phase I and Phase II sources. 6. What Is the Compliance Progress Report? In addition to the NIC, we also promulgated Compliance Progress Report requirements in the 1998 " fast track" rule. See 63 FR 33782. The purpose of the Progress Report was to help regulatory agencies determine if sources were making reasonable headway in their efforts to come into compliance. The Progress Report was required to be submitted at the midpoint of the threeyear compliance period and contain information that essentially built on the information you previously provided in the NIC. For example, if you indicated in the NIC that you needed to make specific physical modifications to your combustion system in order to comply with the standards, you would be expected to describe your progress in making those modifications in your Compliance Progress Report. Although the Progress Report was primarily intended as a tool for the regulatory agencies, we believe it also may have been beneficial to sources as well. For example, the Progress Report could have been used by sources as a mechanism to review and make any necessary changes to their original strategy for achieving compliance. As discussed in the previous section, the Court vacated the early cessation, NIC and * OMB Review Draft*

85 For example, if you reported in your NIC that you intended to upgrade your existing unit, but later determined that it was more appropriate to replace the unit with a new unit, we would expect you to inform your regulatory agency of this change in your compliance plan in your Compliance Progress Report.

231 Compliance Progress Report provisions of the Phase I rule in Chemical Manufacturers Ass'n v EPA, 217 F. 3d 861 ( D. C. Cir. 2000). Although the Court's primary focus was the early cessation provision, it also vacated the Progress Report requirements because it could not determine whether we would have promulgated those requirements absent the early cessation provision. 7. Why Is EPA Requesting Comment on Requiring the Compliance Progress Report for Phase I and Phase II Sources? We believe that the Progress Report would be a useful tool for both regulators and sources in measuring progress toward achieving compliance with the Subpart EEE standards and determining if any revisions to a source's compliance strategy are necessary. Unlike the NIC, however, we do not have practical experience with the application of the Compliance Progress Report, because the Court vacated its requirements prior to their implementation. As a result, we are requesting comment on whether or not the Compliance Progress Report should be required for Phase I or Phase II sources. 8. How Would the Compliance Progress Report Requirement Work? The Compliance Progress Report requirements would be similar to those promulgated for Phase I sources in the June 19, 1998 " fast track" rule ( 63 FR 33782). Within two years of the promulgation of the final standards, you would develop and submit to your regulatory authority a Compliance Progress Report. The Report would include information which demonstrates your progress toward compliance. This could include, for example, completed engineering designs for any physical modifications to the combustion unit that are needed to comply with the standards; copies of construction applications; and binding contractual commitments to purchase, fabricate, and install any necessary equipment, devices, and ancillary structures. In addition, you would be expected to include a detailed schedule that lists the dates for all remaining key activities and projects that will bring you into compliance with the standards. For example, you would include bid and award dates for construction contracts, milestones for groundbreaking, and dates for the approval of permits and licenses. We would also expect you to include in your report any updates or changes to the information you previously provided in your NIC, including if you have changed your compliance plan based on engineering studies or evaluations that you have conducted since your NIC submittal. 85 Sources that intend to cease burning hazardous waste prior to or on the compliance date would still be expected to submit a report describing key activities and projected dates for initiating RCRA closure and discontinuing hazardous waste activities at the combustion unit.

XVII. What Are the Title V and RCRA Permitting Requirements for Phase I and Phase II Sources? * OMB Review Draft*

86 There is no change to our decision to subject Phase I area sources to the same MACT standards and title V permitting requirements as the major sources. For Phase II sources, area sources are required to meet the same MACT standards as major sources, but only for: dioxin/ furan, mercury, carbon monoxide/ hydrocarbons, and destruction and removal efficiency. See Part Two, Section I. A. for more information on regulation of area sources. Therefore, Phase II area sources will be required to obtain a title V permit only for those MACT standards as discussed later in Paragraph C. 4. of this section.

232 In today's notice of proposed rulemaking, we are maintaining the same general approach we took in the 1999 rule with respect to title V and RCRA permitting requirements and the Phase I sources. We feel that this approach, to place the MACT air emissions and related operating requirements in the title V permit and to continue to require RCRA permits for all other aspects of the combustion unit and the facility that are governed by RCRA, is still the most appropriate method to meet our obligations under both statutes. In 1999, our goal in developing a permitting scheme to accommodate both statutes with respect to air emission limitations and standards, was to avoid duplication to the extent practicable and to streamline requirements. We remain committed to that goal, as we revise and refine the permitting approach we finalized in 1999. A. What Is the General Approach to Permitting Hazardous Waste Combustion Sources? In the September 1999 rule, we finalized a permitting approach that places the MACT air emissions and related operating requirements in the title V permit and retains all other RCRA related requirements ( e. g., corrective action, general facility standards, other combustor specific concerns such as material handling, risk based emission limits and operating requirements, and other hazardous waste management units) in the RCRA permit. See 64 FR 52828, 52833 52834 ( September 30, 2000). Under this approach, sources comply with their RCRA emission limits and operating requirements until they demonstrate compliance with the MACT standards by conducting a comprehensive performance test and submitting a Notification of Compliance ( NOC) to the Administrator ( or authorized State) that documents compliance. 86 Upon documenting compliance through the NOC, sources may begin the transition from RCRA permitting to title V permitting. We believe that this approach still makes the most sense in terms of providing flexibility and minimizing duplication between the two permitting programs, while ensuring that there is no break in regulatory coverage. It is also appropriate given where sources will be in the transition process of complying with the MACT Interim Standards upon promulgation of the Phase I Replacement standards and the Phase II standards. The majority of Phase I sources will have initiated a significant modification of their title V permits to include the operating requirements of their NOC and a modification of their RCRA permits to remove duplicative conditions. By this time, permitting authorities and sources are familiar with the current permitting approach and have worked through many issues to make compliance with the Interim Standards and the ensuing transition successful. We feel that permitting authorities and sources would prefer to draw upon their experiences and utilize the expertise they have developed, rather than exploring ways to implement a new permitting scheme. Therefore, we are retaining the same general approach to * OMB Review Draft*

233 permitting for Phase I sources and are proposing to apply this same general approach to Phase II sources in today's Notice of proposed rulemaking: to place the MACT emission standards only in the CAA regulation at 40 CFR part 63 Subpart EEE, and rely on implementation through the air program and operating permit programs developed under title V. 4. What Is the Authority for the Proposals Discussed In this Section? EPA is issuing these proposals to modify RCRA permits under the authority of sections 1006( b), 2002, 3004, 3005 and 7004( b) of RCRA. With regard to the regulatory framework that would result from today's proposal, we are proposing to eliminate the existing RCRA stack emissions national standards for hazardous air pollutants for hazardous waste combustors. That is, after submittal of the NOC established by today's rule and, where applicable, RCRA permit modifications at individual facilities, RCRA national stack emission standards will no longer apply to these hazardous waste combustors. We originally issued emission standards under the authority of section 3004( a) and ( q) of RCRA, which calls for EPA to promulgate standards `` as may be necessary to protect human health and the environment.'' We believe that the proposed MACT standards are generally protective of human health and the environment, and that separate RCRA emission standards are not needed to protect human health and the environment. Refer to Part Four, Section IX. How Does the Proposed Rule Meet the RCRA Protectiveness Mandate? for a discussion on this topic. In addition, RCRA section 1006( b) directs EPA to integrate the provisions of RCRA for purposes of administration and enforcement and to avoid duplication, to the maximum extent practicable, with the appropriate provisions of the Clean Air Act ( and other federal statutes). This integration must be done in a way that is consistent with the goals and policies of these statutes. Therefore, section 1006( b) provides further authority for EPA to eliminate the existing RCRA stack emissions standards to avoid duplication with the new MACT standards. We are not proposing, however, that RCRA permit conditions to control emissions from these sources will never be necessary, only that the national RCRA standards appear to be unnecessary. Under the authority of RCRA's `` omnibus'' clause section 3005( c)( 3); see 40 CFR 270.32( b)( 2)), RCRA permit writers may impose additional terms and conditions on a sitespecific basis as may be necessary to protect human health and the environment. Thus, if MACT standards are not protective of human health and the environment in an individual instance, RCRA permit writers will establish permit limits that are protective. In RCRA, Congress gave EPA broad authority to provide for public participation in the RCRA permitting process. Section 7004( b) of RCRA requires EPA to provide for, encourage, and assist public participation in the development, revision, implementation, and enforcement of any regulation, guideline, information, or program under the Act. 2. Is EPA Proposing a Different Permitting Approach for New Sources? As discussed above, we are maintaining the same general permitting approach as before. However, we are proposing to eliminate the unintended result of the previous regulatory construct, which caused new sources to initially be subject to the RCRA air emission and operating requirements. In particular, we want to specify that any hazardous waste burning incinerators, cement kilns, lightweight aggregate kilns, boilers, and hydrochloric acid production furnaces newly entering the RCRA permitting process ( e. g., sources that are seeking an initial * OMB Review Draft*