Opinion ID: 621128
Heading Depth: 3
Heading Rank: 5

Heading: Auxiliary Stacks/30-Meter Stack

Text: Montana Sulfur next argues that the EPA acted arbitrarily and capriciously by imposing emission limits and monitoring requirements regarding Montana Sulphur's auxiliary stacks and 30-meter stack. Montana Sulphur argues that the requirements are unnecessary to comply with the NAAQS because the emissions are extremely small and have no practical effect on NAAQS. [11] It also contends that the worst case scenario calculation by the EPA ignores reality because Montana Sulphur cannot vent all five boilers to the auxiliary stacks and still operate its plant. As discussed above, the EPA partially disapproved Montana's limitations on the auxiliary stacks and the 30-meter stack because there was no restriction on the sulfur content of the fuel when exhausting through these stacks and because the SIP lacked a monitoring method to make the mass emission limits practically enforceable. 67 Fed.Reg. at 22,170. The FIP adopted the same mass emission limits that the state had imposed in the SIP12 lbs/3 hoursand added monitoring requirements to ensure compliance with the limits. 73 Fed.Reg. at 21,451-21,452. As for the arbitrariness of the actual limits and monitoring requirements, it was reasonable for the EPA to use the state's original emission limitations for consistency because they were a piece of the state's overall control strategy supporting attainment. The EPA further points out that (1) the final FIP was revised to allow Montana Sulphur to use its existing length-of-stain detector tubes for monitoring rather than requiring the portable analyzers suggested in the initial proposal, 73 Fed.Reg. at 21,446 (noting that the final FIP was similar to the state operating permit requirements that already applied to Montana Sulphur); and (2) the final FIP increased the concentration limits on the fuel burned in the units from 100 ppm/3 hours to 160 ppm/3 hours to accommodate Montana Sulphur's concern that it was too restrictive, noting that modeling using 160 ppm for up to three hours would still meet attainment requirements (but not if emissions were at this level for the entire day) and that evidence indicated Montana Sulphur should already be within these limits in light of the SIP's requirement of burning only low sulfur gas and the fuel gas scrubbing technology it uses. 73 Fed.Reg. at 21,446-47. The EPA also explains that its modeling assumption that all units were venting to the stacks, whether this would ever happen, was a way of simplifying monitoring and compliance for Montana Sulphur. Under this model, Montana Sulphur needed only to measure H2S ppm concentration (using its existing monitoring device) to determine compliance, whereas direct compliance per boiler stack would either require additional monitoring equipment or methods or be unreliable due to potential variation in boiler use and venting practices. 73 Fed.Reg. at 21,446-21,447 & 21,452. The EPA sums up its decision in its final FIP: We believe additional monitoring equipment would need to be installed, or additional monitoring would need to be performed, at greater expense to [Montana Sulphur], to achieve adequate method to determine direct compliance with the mass emission limits. The concentration limits we are imposing are reasonable, can be monitored at reasonable cost, and will ensure protection of the NAAQS. 73 Fed.Reg. at 21,447. Thus, the specific emission limits and monitoring requirements imposed by the FIP, based on revised emission models and that allow Montana Sulphur to use existing technology, were not arbitrary or unreasonable.