On Wednesday, July 21, 2010, the EPA announced its intention to partially approve and partially disapprove a State Implementation Plan (SIP) revision submitted by the State of Colorado regarding its Regulation 1 plans. The agency's response to Colorado's early plan could provide an excellent opportunity for industry and other states to gauge what the federal agency is looking for in its state rules for air emissions.

In general, the agency was fine with the state's proposal to use a weighted average of emissions to calculate allowable 24-hour limits, but refused to allow Colorado to relax its overall SO₂ levels for refineries. The EPA also nixed a proposal that would give the state agency's director discretionary powers to account for special circumstances, noting such a provision could be used as a loophole, giving an industry-friendly governor too much power to help friends, or conversely, an environmentalist governor too much power to nail polluters without going through proper procedures.

Regulation 1 provides certain emission controls for opacity, particulates, CO and SO₂. The revision involves the deletion of obsolete, the adoption of new, and the clarification of ambiguous provisions within Regulation 1.

Notably, the agency approved approve Colorado's revision to the method of computing compliance with emission limits for cement manufacturing and petroleum refining (Sections VI.A.3.e, VI.A.3.f., VI.B.4.e, and VI.B.4.g(ii)). According to the agency, the revision "more accurately reflects the daily processed-based SO₂ emissions limits by using actual hours of operations as an averaging time when the facility does not operate for an entire 24-hour period."

Colorado also revised the method in Section III.A.1.d for calculating particulate matter emission rates for two or more fuel-burning units connected to a common opening. Previously, the method summed the allowable emissions from the fuel-burning units; the revised method uses a weighted average of the individual allowable limits.

The EPA turned down the "director's discretion" provision in Colorado's July 31, 2002 Regulation 1 SIP revision submittal. The federal agency said it feared the provision would give the state the ability to arbitrarily modify requirements for stationary sources. The affected sections, which must be re-written, include those for performance testing, fuel sampling, and alternative compliance procedures.

The agency didn't rule out discretionary powers entirely, noting the state may retain some flexibility through the authorities under 40 CFR 70.6(a)(1)(iii) and the policy in the EPA's White Paper No. 2.

Also turned down were relaxed SO₂ emission limits for petroleum refineries (Section VI.B.4.e) and shale oil refineries (Section VI.B.4.g(ii)). The existing SIP approved rules for these sources limit SO₂ emissions to 0.3 lbs. per barrel of oil processed per day. The revised daily limit of 0.7 pounds per barrel. This wasn't a big surprise, as the state itself had already notified the EPA (on Aug. 8, 2006) that it planned to nix that part of the 2002 plan anyway, and keep its current categorical limits of 0.3 lbs. per barrel, as well as require non-specified entities to still keep it to 2 tons per day, using BACT.

Source: Federal Register Notice