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Federal Register / Vol. 86, No. 32 / Friday, February 19, 2021 / Proposed Rules
tkelley on DSKBCP9HB2PROD with PROPOSALS

include extra restrictions regarding the use of prescribed fire during the problematic cold weather season when these areas can experience air stagnation events. Specifically, the Oregon SMP at OAR 6290480135 prohibits prescribed burning on Red woodstove days in the SPZ from December 1
through February 15 and provides additional cautionary requirements for prescribed burning in SPZs on non Red woodstove days from November 15 through February 15.
The 2014 and 2019 submittals establish more protective burn authorization levels than those in the previously SIP-approved SMP through the establishment of sub-NAAQS
intrusion thresholds at OAR 629048
000527.8 For example, although there is no one hour NAAQS for PM2.5, ODEQ
has established a 1-hr threshold of 70
mg/m3, further bound by the 24-hr threshold of 26 mg/m3 approximately 75% of the NAAQS for determining whether or not a burn will be permitted.
If PM2.5 is at or above the sub-NAAQS
thresholds, the 2019 Submittal provides that a prescribed burn would not be approved. Likewise, if the PM2.5 is lower than the PM2.5 thresholds, but additional smoke would likely cause an exceedance of the thresholds, the burn would also not be approved. The submitted revisions contain an exemption process from the 1-hr PM2.5
intrusion threshold but the exemption imposes additional requirements and conditions OAR 6290480180. The revised Smoke Management Plan also includes provisions for removing a communitys exemption from the 1-hour intrusion threshold if an area has had three or more 24-hour threshold exceedances in five years.9 The revised plan also includes a provision for revoking the exemption if the SSRA is within one exceedance of a NAAQS
violation. Also, SSRAs that are in a nonattainment with the NAAQS will not be eligible for an exemption see 629048
0180 3e and f. There is not an exemption process for the 24-hr PM2.5
threshold of 26 mg/m3, therefore the revised Smoke Management Plan is 8 In its response to comments during the state public process, Oregon acknowledged that the proposed 2019 SIP amendments have the effect of allowing for an estimated increase of prescribed fire use by 80%. However, EPA proposes to conclude the burn-specific authorization criteria based on ambient monitoring data, included in the proposed SIP amendment, are sufficient to ensure continued protection of the NAAQS.
9 From 6290480180 3d, ODF and DEQ may revoke the exemption if there are repeated three or more in five years smoke intrusions that exceed the 24-hour average threshold or prescribed burning contributes to two or more NAAQS exceedances.

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more protective than the 24-hr PM2.5
NAAQS.
The proposed revisions also include new best burn practices and emissions reduction techniques at OAR 629048
0210 allowing the burning of polyethylene coverings used to keep piles of slash and thinning debris dry.
To determine the efficacy of polyethylene coverings, ODF and EPAs Office of Research and Development contracted with a testing firm to conduct a study 10 of emissions from wet versus dry covered and uncovered piles. The study showed that wet piles burn slower and produce more emissions on a mass basis due to incomplete combustion than dry piles.
In general, burning dry piles, even with polyethylene still in place, produces less criteria pollutant emissions than burning uncovered wet piles. Therefore, the revisions allowing for burning polyethylene to facilitate a reduction in emissions are more protective of the NAAQS.
Some additional changes in the 2014
and 2019 Submittals that EPA proposes to determine are either more protective than current SIP requirements or not expected to result in significant NAAQS
impacts include expanding SPZ
boundaries 11 to include the areas from which prescribed burning could cause an impact and changing SSRA 12
boundaries to better align with airshed boundaries. Prescribed burning is generally not expected to make significant contributions to the remaining criteria pollutants Lead, CO, NOX, and SO2 due to a combination of factors. Monitored values in Oregon for these pollutants are well below the level of the NAAQS; wildfires are not known to be significant contributors of airborne Lead or SO2, and finally, prescribed burning in any one geographic area will be infrequent enough that it is not expected to create elevated concentrations that violate the NAAQS
for any of these criteria pollutants. For additional information regarding these pollutants see Oregon SMP 110
Discussion, which is included in the docket materials for this action.
Oregons Smoke Management Plan revisions include OAR 6290480130
Visibility Objectives, which clearly state that it is the intent under the Smoke Management Plan to comply with Regional Haze requirements as 10 A copy of the study is included in the Docket materials for this action. See: Attachment G of Oregon SMP 110 Discussion.
11 As described in OAR 6290480137 SPZ
Contingency Plan Requirements.
12 SSRAs are areas designated for the highest level of protection under the Smoke Management Plan OAR 629048000526.

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identified in the Oregon Regional Haze Plan. The revised Smoke Management Plan also enhances the Regional Haze Plan by incorporating practices to minimize visibility impacts to the Kalmiopsis Wilderness and Crater Lake National Park into the Smoke Management Plan.13 Oregons 5-Year Progress Report approved May 17, 2019
83 FR 22853, demonstrates that the long-term strategy and emission control measures in the existing Regional Haze SIP are sufficient to enable Oregon to meet all established reasonable progress goals. EPA proposes to find that Oregons smoke management revisions do not constitute a relaxation in Oregons Regional Haze SIP approved August 22, 2012 77 FR 50611 because Oregons revisions do not alter limits on the quantity of light impairing pollutants emitted from prescribed burning and OAR 6290482 clearly states it is Oregons intent to operate their Smoke Management Plan in a manner consistent with the Oregon Regional Haze Plan.
IV. Technical Corrections EPA is making technical corrections to provisions previously approved as revisions to the Oregon SIP pursuant to CAA 110k6. In 2012 we approved 77
FR 50611 Oregons revised Smoke Management Plan at OAR 629048
0001 through 0500 which replaced OAR 6290430043 but we failed to update 40 CFR 52.1970c, Table 2. We are correcting Table 2 to reflect the 2012
approval by removing OAR 62943
043 and adding the portions of OAR
629048 state effective January 1, 2008
that were not revised by Oregons 2014
or 2019 Submittals.
We are correcting the identification of the Oregon SIP at 40 CFR part 52.1970c, Table 2 by adding:
OAR 6290480100, Regulated Areas state effective 1/1/2008;
OAR 6290480160, Bear Creek/
Rogue River Valley SSRA state effective 1/1/2008;
OAR 6290480300, Registration of Intent to Burn state effective 1/1/2008;
OAR 6290480330, Emission Inventories state effective 1/1/2008;
OAR 6290480400, Coordination with Other Regulating Jurisdictions and for Other Pollutants state effective 1/1/
2008.
We are also making technical corrections to the Oregon SIP at 40 CFR
part 52.1970e, Table 5, Section 3, by revising the reference to Oregons 13 See our proposed approval of Oregons Regional Haze Progress Report 83 FR 11927, March 19, 2018 which was finalized May 17, 2018 83 FR
33853.

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