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OAR Box 1875 

Prepped by Ollie Stewart 

Document Number: 

28) ll-E-46 

Docket Number: 

A-90-19 

Printed 12/1/2008 11:12:45 AM Sheet 28 of 86 
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^ A-90-19 

ll-E-46 

DATE: July 6, 1992 

SUBJECT: Hazardous Organic NESHAP (HON) Meeting with State 

Representatives 

Attached are materials distributed by the National Governors 

Association's Air Implementation Task Force for discussion during 

a teleconference with EPA personnel on July 6, 1992. An agenda 

and an issue paper on interpollutant averaging are attached. 

Attachments: 2 

\ \**- - f, \ t* "y 

mgmll.memos.det 
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NATIONAL 

GOVERNORS' 

ASSOCIATION 

Rov Romer 

Governor of Colorado 

Chairman 

Carroll A. Campbell Jr. 

Governor of South Carolina 

Vice Chairman 

Raymond C. Scheppach 

Executive Director 

Hall of the States 

444 North Capitol Street 

Washington, D.C. 20001-1572 

Telephone (202) f>24-5.'00 

* * NOTE: REVISED AGENDA 

The State Environmental Commissioners' 

Air Implementation Task Force 

Conference Call With EPA -- Monday, July 6, 2:00 P.M. EDT 

Conference Line: 202-260-3844 

REPORT FROM HON WORKGROUP 

• Interpollutant Averaging 

• Discount Factor 

STATUS REPORT 

• Proposed Enhanced I/M Rule (was due 11/91; currently at OMB; suits pending) 

• Final Permit Rule (impact of DOJ opinion) 

• Transportation Conformity Regulations (was due 11/91; SIP revisions due by 11/92; suit 

pending) 

RULES/ISSUES ON THE HORIZON 

• States Facing Potential Law Suits for Not Acting On Key Rules That Are Delayed, e.g., 

enhanced I/M by November 1992 

• Proposed Guidance or Standards for NOx in Tides I and IV: What Is RACT? 

• New Source Review Rules for Nonattainment Areas (emission offset rules) 

• Final Rule on NSR Requirements for Electric Utilities 

• Incineration Rule: Delay Is Holding Up State Permitting Activity 

• Mobile Air Conditioner Refrigerant Recycling Requirements 
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Discussion Sheet For HON Workgroup 

intArpollutant Averaging 

Objective 

To obtain consensus on a framework — as specific as possible — for interpollutant trading. 

Background 

The interpollutant averaging issue is addressed only briefly in the draft HON rule. The 

rule indicates (pages 165-166) that averaging should not result in "increased overall 

toxicity of emissions." The rule also suggests that source operators avoid averaging 

schemes that increase overall toxicity because "such increases could result in additional 

controls being required after the subsequent evaluation of the residual risk associated with 

individual sources and the source category as a whole." Absent in die rule is any 

discussion of a system that permits "risk equivalent" averaging. The Air Implementation 

Task Force agreed mat no interpollutant averaging should occur until such a system was 

developed. 

An objective of the HON workgroup is to examine whether a workable system for "risk 

equivalent" interpollutant averaging can be developed and whedier such a system can be 

supported by states, industry, environmental groups, and EPA. 

A system for interpollutant trading is being developed under Section 112(g) (which 

addresses modifications to existing sources mat result in increases of HAPs). EPA is 

required under die Act to develop a hazard ranking system for the 190 HAPs identified in 

Tide m. For consistency, it would be desirable to use die 112(g) system as die basis for 

interpollutant averaging in die HON. 

The system EPA is considering puts the pollutants into bins which reflect their toxicity and 

risk. Issues relating to this are covered in the enclosed Held letter to EPA, in the Shapiro 

letter to the Science Advisory Board, in the STAPPA/ALAPCO Resolutions, in die 

STAPPA/ALAPCO letters to Jordan and Shapiro, and in EPA's May 26 presentation to 

die Clean Air Aa Advisory Committee. 

Reflecting another approach, an indexing scheme was developed in the Early Toxic 

Reductions (ETR) proposal. As indicated on pages 4-7 of die ETR summary, a weighting 

factor was assigned to 35 highly toxic pollutants based on dieir toxicity. (All other 

chemicals have a weighting factor of one.) STAPPA opposes die ETR indexing systems 

and prefers trading pollutants by "bins" in which pollutants are grouped according to 

similarity of risk. 
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<s 

Current Options Or Proposals: Bins Vs Indexing 

The Bin Approach 

The bin approach puts each pollutants in a bin according to its toxicity/carcinogenicity. A 

scheme could be developed where averaging would be allowed widiin bins and from 

higher-risk bins (overcontrolled unit) to lower-risk bins (undercontrolled unit). In duafbin 

process, consideration could be given to HAPs which tend to bioaccumulate and for HAPs 

with no safety threshold. The main advantage to binning is that it acknowledges the 

uncertainty inherent in the data on toxicity and carcinogenicity and allows approximation 

in the decision. 

The Indexing Option 

Indexing, which is used in the ETR proposal, assigns a number to each pollutant according 

to its toxicity. Airy trades that occur must'take the total toxic emissions into account 

based on die assigned weights. This system appears to allow risk equivalent averaging, 

but does not take into account the inherent uncertainty associated widi existing data on 

these pollutants. Each HAP and its relationship to all other HAPs must be determined and 

this may not be justifiable given the current data. Indexing may, therefore, result in 

inconsistencies. 

items To Consider In Reviewing The Above Options 

• Is there enough scientific data to support a "risk equivalent" averaging scheme? 

• Is speciation of emissions possible? If not, how can groups of HAPs be traded? 

• Should a scheme for averaging high-risk pollutants be devised to address 

bioaccumulation of pollutants? 

• Should reductions of lower-risk pollutants be allowed to offset undercontrolled higherrisk pollutants? 

• Should certain highly toxic/carcinogenic pollutants be prohibited from averaging, be 

limited only to overcontrol to generate credits, or be allowed to average only among 

themselves? 

• Should the scheme be updated regularly by EPA to incorporate new 

information on pollutants? If yes, how frequently? Should changes in hazard 

rankings require immediate changes in existing averaging schemes? 

National Governors' Association Pap 2