To: Re: EPA should rely on benefit-cost analysis, rather than cost-effectiveness analysis,

The MACT floor represents the minimum stringency levels for new and existing large MWC units, based on levels of emissions control achieved in practice by the best-performing 12% of units in the category.6 Each regulatory option EPA considers must be at least as stringent as the MACT floor.7 EPA also must examine a more stringent beyond-the-floor regulatory option and consider the various impacts. [...] 2 emissions per year.13 Because the second option “provides the most cost-effective means to maximize emissions reductions”—that is, it has the highest ratio of emissions reduction to cost, according to EPA’s analysis—EPA selects it as the preferred alternative.14 EPA also conducts a regulatory impact analysis (RIA) where it assesses the benefits and costs of the different regulatory options.15 In. [...] In the 2005 Clean Air Mercury Rule, which addressed mercury standards for coal-fired electric utility steam generating units, EPA estimated the marginal cost of mercury reductions for its chosen regulatory option to be $39,000 per pound (in 1999$).35 That’s equivalent to nearly $67,000 per pound in 2022$, the unit of analysis in the Proposed Rule.36 To put this in perspective, in the Proposed Rule. [...] EPA Should Consider the Distributional Effects of Each Alternative When Selecting Among Regulatory Options To better identify the welfare-maximizing alternative, EPA should also consider the distributional impacts that the proposed scenario and the other alternatives may have, including benefits and costs to environmental justice communities. [...] While EPA concludes that consideration of unmonetized effects would increase the net benefits of its proposed regulatory alternative,71 it does not analyze how consideration of the unmonetized benefits might affect the net benefits of the more stringent alternative.