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OAR Box 1878 

Prepped by Charmelle Mathews 

Document Number: 

70) ll-F-33 

Docket Number: 

A-90-19 

Printed 11/28/20081:21:24 PM Sheet 70 of 145 
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A-90-19 

ll-F-33 

TO: Docket A-90-19 

FROM: Jan Meyer, SDB 

DATE: October 30, 1992 

Attached are two sets of draft language received from OMB 

for inclusion in the discussion of the control decision for 

process vents in the HON. Attachment 1 was received during the 

week of 10/13 and Attachment 2 was received during the week of 

10/19. These materials were discussed as part of the discussions 

with OMB as part of the review under Executive Order 12291. 
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EPA is today proposing a range of control levels for SOCMI process ueits that 

includes the floor control level required by section 112(d)(3), and three ffinstrcxhre alternative 

control levels which axe more stringent than the floor. EPA currently has no analysu of the 

benefit* to human health that would Justify selecting any control level above the floor. Thai, 

EPA will perform such an analysis prior to promulgation of the final rule to determine 

whether sufficient benefits indeed exist, and will base its final selection of any control 

requirements more stringent than the floor oo the results of mis aosryals. 

The time oontrol levels proposed today which go beyond the floor ate based on 

EPA's 1989 and 1990 benzene NESHAP decisions. Ift benzene, EPA used t two-part 

process tor selecting control levels. Rrst, the Agency determined that 1 maximum individual 

upper-bound uveas lifetime cancer risk of one in 10,000 lifetimes (IO-*) constituted an 

acceptable risk. Second EPA considered a range nf factors moiudmg costafiectiveness to 

provide an ample margin of safety. Cost was not a factor in establishing the maximum 

acceptable risk threshold. 

The appropriate benchmark for evaluating the oc^-effectiveness of the benzene 

standards is about $900/Mg. This ia a rough average of the cost-^Kectivenesa ci the control 

levels selected for cote by-preiduet recovery (16,500 Mgs cc*fcoitod at $97QVMg) and storage 

vessels (560 to 1,200 Mgs controlled at S123/Mg to $909/Mg). Other categories of emission 

points bad cost-effectiveness ratios substantially greater than these levels, but they represent 

the high cost of meeting the acceptable risk threshold rather than the result of balancing 

emission reductions against cost Thus, thoy do net accurately characterize the costefiectrveness of the benzene decision in the range where cost is a relevant Actor of concern. 

The cwHrffcvtiveness ratio usodated with the benzene decision reflects the estimated 

cancer risks associated with benzene. Thus, it provides only a guide as to the level of coat 

which would be appropriate to bear to reduce the risks associated with the wide range of 

HAPs regulated under the HON. Therefore, die Agency is u*ug the nenirnc costeffectiveness ratio merely as a preliminary estimate of the risks that are associated with 

HAPs regulated under the HON. The Agency expects thai its benefiu analysis frx reducing 

HON amissions may yield risk estimates mat differ from estimates obtained in the benzene 

decision. 

Thus, in addition to the floor control level, EPA is today proposing control levels of 

$900/Mg, $1,800/Mg, and $2,7O0/Mg. The first alternative is roughly equal to the value 

chosen in the benzene NESHAP. Tho second and third alternadvM s « twice and thrice me / 

benzene NESHAP value, respectively. EPA currently believes that its benefits analysis is 

likely to show tiiat control levels within mis range are c^-effective, taking into account 

differences in risk between benzene nod the inUiurc of HAP* emitted from EON process 

units. EPA requests comments, including data and methodological suggestions, which would 

be useful lor ascertaining the risks of HON* process unit emissions relative to benzene, 

including potency and exposure estimates and techniques for estimating me fan&oence of aU 

relevant health effects. 
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-\p-lnaert "A" 

Given the scope and potential impacts of this rulemaking, 

EPA recognizes the naud to continue to refine its estimates of 

the costs and benefits of ths rule. The Agency intends to 

collect additional data and will conduct subotantial new analyses 

prior to finalizing today's rule. 

The new analyses will be conducted in accordance with the 

existing Agency guidance on Regulatory Impact Analysis and tha 

Regulatory Impact Analysis Guidance published in the 1990 

Regulatory Program of the United States. The analyses vill 

explicitly examine both the costs and the health and 

environmental benefits for the key regulatory requirements 

contained in the proposal. Upon completion of the revised 

analysis, EPA will solicit comment on the results of the analyses 

and the methodology used to derive them. The Agency will then 

assess these comments/ along with comments which have been 

received previously on the proposed rule. 

Through these actions EPA will ensure that the net social 

benefits (including environmental and health benefits) of the 

rule proposed today are maximized, taking into account costs, 

risks, and the minimum technology requirements implied by the 

floor, rf the revised RIA, together with the comments received, 

demonatrate that the rule proposed today does not achieve this 

outcome, the Agency will make appropriate modifications to the 

final rule. 

[Adapted fromi Corrective Action NPRM, 55 FR 390864-65 J