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## s~i-z~ ~j~-e~ together. In this case, the gasoline loading limit would effect

## VOC emissions which are defined precursor pollutants to ozone. Tesoro is located in a maintenance areafor ozonewhich means, thatforan increase in VOC emissions ofat least 40 tons peryear, the requirements ofthe PSD program apply. UDAQ has conducted a review ofthe limitation in question and has found no evidencethatthis gasoline loading limit was taken forthe express purpose ofavoiding major NSR. This limitwas put in place in the 1990s to demonstrate that no increase in emissions would occurfrom the installation oftwo tanks. Ratherthan conducting a complicated tank-by-tankindividual throughput emission approach at that time, Tesoro instead used the total throughput atthe loading rackas a surrogate. By limiting the total throughputatthe loading rack, the throughput at the individual tanks feedingthat loading rack is similarly limited, and thereforethetotal emissions ofVOC from those tanks is also limited.
UIJAQ is including the following additional analysis showing that even ifthe removal ofthat limit could have impacted the majorNSR status ofthe original project (a pointwith which UDAQ disagrees), no changes to the ITAorAO would be required (see the following).

Ifthe possibility ofmajorNSR review had resulted, then UDAQ agrees that 40 CFR 52.21 (r)(4) would be the applicable regulation. Incorporated by reference into R307-405-1 9 Source Obligation, that regulation reads as follows:

Atsuch time that aparticularsource or mod~flcation becomes a majorstationarysource or major modification solely by virtue ofa relaxation in any enforceable limitation which was established after August 7, 1980, on the capacity ofthe source or mod~flcation otherwise to emit apollutant, such as a restriction on hours ofoperation, then the requirements orparagraphs 

### U) through (s) ofthis section shall apply to the source or mod~/Ication as though construction had notyet commenced on the source or modification.
Consistent with the response to comment #13, UDAQ interprets this to mean that should UDAQ relax a limit previouslytaken to avoid majorNSR, then the entire project, including the original action which avoided major NSR, must be re-evaluated as though the entire projectwere being proposed today. In otherwords, the original project (or more to the point both the original and the new project) does not automaticallybecome major, but thatthe entire combination project must be evaluated to determine its major or minor modification status. Again, this analysis has alreadybeen completed. As found in Table 3-3 (page 37) ofthe revised NOT, gasoline and diesel loadoutVOC emissions are shown as increasing by 14.72 tpy. These values are projected actual emissions, as no limitation on plant-wide VOC emissions has been established forthe refinery. Including the changes to VOC emissions from other affected components at the refinery, the total increase in projected actual emissions equals 28.12 tpy, which is well belowthe 40 tpysignificance threshold. Therefore the modification remains minor. Accordingly, the comment is noted, and no changes were made to the ITAs.

Comment #15: “The calculation ofproduct demand growth exclusion is not based on adequate evidence in the record. Tesoro’s calculation ofdemand growth emissions is not legally defensible. For example, Tesoro based its demand growth emission estimate on “the maximum actual throughput, firing rate or emissions rate” experienced at all units (except loading racks and storage tanks) during a 1 month period. NOl at 27. However, this hypothetical rate must be both legally

10and physically possible. In otherwords, the rate must be one thatthe facilitycould physically

achievewhile still complying with its permit and applicable law.”
UDAQ Response: The commenter seems to be making a general statement thatjust because a source has demonstratedthe capacityto operate at a particular rate orthroughput it does not mean it can actually operate atthat rate orthroughput. Specifically, the commenter implies that an analysis must be made of this increased capacityto verifythat itwould meet all other applicable rules, regulations and requirements. IJDAQ agrees that such an analysis is required. However, UDAQ disagrees thatthis analysis was not completed. Consistentwith the requirements ofR307-1 01-2, R307-401-3 and R307- 403-3, UDAQ reviewed the validity ofthe supplied calculation methodology and the accuracyofthe resulting projected annual emissions (see NOTAppendix B). In no case did the projected emissions exceed any short- or long-term emission limitations as found in the most recentAO issued to Tesoro (DAQE-AN103350056-12). This was explained in the source plan review (RN103350058-12) for DAQE-1N103350058-12 under Reviewer Comment #8. See also response to comment #25 for more information.

Comment#16: “Tesoro also uses a 98% utilization factor to calculate its demand growth emission estimate. NOl at 26-27. However, there is no support for this ufflization factor in the record. In otherwords, the record does notsupport the contention that the facility is physically capable of operating atthat rate for any extended period oftime, much less ayear. Further doubt is cast upon this utilization factor because elsewhere Tesoro uses a 95% utilization or annualized rate that assumes a 95% capacityfactorto accountfor (SRU) unit downtime. NOl at B-30.”
UDAQ Response: UDAQ disagrees with this comment. In EPA’s only policy determination on the use ofthe demand growth exclusion, found in a letterfrom EPA Region 4 (found in the NOT as Attachment D, and also attached to this response memorandum), EPA states that it agrees that “Georgia Pacific may use the highest demonstrated average monthlyoperating level duringthe baseline period as an approximation ofthe level ofoperation thatthe units ‘could have accommodated’ duringthe baseline period.”

The EPA letter goes on to state that once a source has determined the projected actual emissions following the proposed project, the source is allowed to exclude from the projection “that portion ofthe unit’s emissions following the projectthat an existing unit could have accommodated” during the baseline period and that are unrelated to the particular project.

These statements allowTesoro to exclude all emissions that were capable ofbeing accommodated during the baseline period

—i.e. 100% ofall demonstrated emissions not associated with the newproject. Tesoro took a more conservative approach and applied a 98% utilization factor on top ofalreadydemonstrated maximum monthly emissions (actual emissions) to account for anynormal reductions in production that take place.

The comment also addresses the use ofa 95% capacityfactor atthe SRU versus the 98% utilization factor applied for all other equipment. When UDAQ originally analyzed this information, it assumed thatthe 95% capacityfactorwas derived from the PM10 SIP requirement ofinstalling a 95% efficient SRU, and that this 95% factorwas then applied to the afready adjusted emissions forthe SRU (emissions adjusted bythe 98% utilization factor discussed above). This assumption was based on the difference between the terms “capacity” and “utilization” thatwere applied to each factor.
11However, this assumption was incorrect. Tesoro has since pointed out thatthe 95% factorwas a

typographical error, and this is demonstrated in Attachment B-14 ofthe NOT. While the first footnote on page B-30 (the second page ofAttachment B-14) does referencethe 95% capacityfactor, this factordoes not appear in any ofthe calculations ofthat attachment. The 98% utilization factor does appearwhen calculating the throughputthe unit was capable ofaccommodating (second table on page B-30). Upon receiving this clarification from Tesoro, UDAQ verified the equation ofconcern and determinedthatthe original calculations were correct and consistent.

- Comment#17: “Although the NOl purports to aggregate the CONO. and Overhead Condensing Projects with the Waxy Crude Project, there is no analysis or evidence in the record assessing the emissions from these projects.”
UDAQ Response: UDAQ disagrees with this comment. The emissions from both projects are included in the emission calculations forthe Waxy Crude Processing Project. The commenteris perhaps confused that these emissions are not included becausethey are not listed as a separate line item. This is because the calculation methodologyused for determining the emission increase from any project (including one which is aggregated with previouslypermitted projects) is to calculate the difference between (total) projected future actual emissions and established baseline actual emissions. The baseline period chosen byTesoro does not include emissions from the CONOx and Overhead Condensing Projects because these two projects have not yet been constructed. Projected future actual emissions include all changes to the FCCU (and other equipment) related to the combined Waxy Crude Processing, CONOx and Overhead Condensing Projects. As these projects all involve changes at the FCCU, the final FCCU emissions are assumed to include all ofthe changes associated with all three projects in combination. The commenter appears to assume that these two projects have alreadybeen constructed and are in operation, based on the following section ofthe comment:

At the same time, it is important to note that, as with projected actual emissions, baseline actual emissions shall includefugitive emissions and emissions associated with startups, shutdowns, and ma~functions. Therefore, 

## ~fthe CONOx and Overhead Condensingprojects result in anyfugitive emissions or emissions associated with startups, shutdowns or ma(functions, those emissions must also be included in the company’s calculation ofprojected emissions.
The baseline emissions include startup, shutdown and malfunction emissions which occurred duringthe baseline period. UDAQ required Tesoro~to include startup and shutdown emissions in the calculation of projected actual emissions; however, UDAQ does not include possible but unknown and un-calculable malfunction emissions in the calculation ofprojected emissions.

Comment #18: “At the same time, it is importantto note that, as with projected actual emissions, baseline actual emissions shall include fugitive emissions and emissions associated with startups, shutdowns, and malfunctions. Therefore ifthe CONOx and Overhead Condensing projects result in any fugitive emissions or emissions associated with startups, shutdowns or malfunctions, those emissions must also be included in the company’s calculation ofprojected emissions; however, they were not included.”

. UDAQ Response: The responseto this comment was included in response to comment #17.

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