April 17, 2019 Administrator Andrew Wheeler US Environmental

April 17, 2019 Administrator Andrew Wheeler US Environmental Protection Agency 1200 Pennsylvania Avenue, NW Washington, D.C. 20460 Docket No. EPA-HQ-OAR-2018-0794 Subject: Comments on “National Emission Standard for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units—Reconsideration of Supplemental Finding and Residual Risk and Technology Review” As academic researchers studying mercury fate, transport, and impacts, we appreciate the opportunity to comment on the Reconsideration of Supplemental Finding and Residual Risk Technology Review. We write to encourage the Environmental Protection Agency to withdraw its Proposed Finding and Residual Risk Review, given limitations in its assessment methodologies and developments in scientific research on mercury processes and impacts since 2011. This assessment is based on our own research (Giang and Selin 2016; Perlinger et al. 2018; attached; Angot et al. 2018), as well as our review of relevant scientific literature. In the below, we focus on mercury as one important component of Hazardous Air Pollutants (HAPs). Our comments are in response to solicitations for comments C-2 and C-24. (C-2) The Regulatory Impact Analysis (RIA) from 2011 quantifies a very limited range of mercury- related benefits of regulation. Recent evidence indicates that benefits that were unquantified in the RIA may be substantial, and larger than the subset that were monetized. In Giang and Selin (2016), we estimated the benefits of the Mercury and Air Toxics Standards (MATS) policy for US populations. Annualized, our estimates out to 2050 are $3.7 billion/year, using a similar methodology to the RIA. Although methodological differences between our analysis and the RIA prevent direct comparison of numerical results, our research suggests that including a larger subset of health endpoints (IQ and heart attacks) and affected populations (consumers of self-caught freshwater fish and consumers of commercial marine and estuarine fish in the US market) may lead to mercury-related benefits estimates that are orders of magnitude larger than those reported in the RIA. Considering these additional mercury-related benefits could result in benefits that are of comparable magnitude to estimated costs (Rice et al. 2010; Grandjean and Bellanger 2017). Other recent research supports the conclusion that the subset of mercury-related benefits monetized in the RIA represent an incomplete picture of mercury impacts—both in terms of health and wellness impacts considered, and in the populations considered. There are several health benefits from reducing mercury emissions that could not be quantified in the RIA: cardiovascular effects, neurobehavioral effects aside from IQ loss, and immune endpoints (Karagas et al. 2012; Roman et al. 2011; Genchi et al. 2017). While efforts to develop dose-response relationships for use in regulatory benefit-cost analysis are underway, these potentially large health benefits should be taken into account in a holistic assessment of benefits and costs. Other benefits to individual and community health and well-being that are not easily quantifiable should also be included in a holistic assessment of benefits and costs, such as socio-cultural integrity (Ranco et al. 2011; O’Neill 2004). New evidence has also affirmed the importance of considering additional exposure pathways to self-caught freshwater fish: US Electricity Generating Units (EGU) also contribute to mercury pollution in coastal fisheries, and marine fish make up the vast majority of seafood diet for the US population as a whole (Sunderland et al. 2018, 2016). In the Proposed Finding, the EPA affirms that benefits described above that were not quantified in the RIA “are relevant to any comparison of the benefits and costs of a regulation” (p. 2678). If the EPA chooses to focus only on benefits associated with HAPs in its “appropriate and necessary” determination—an approach that does not consider the full public health benefits of MATS—it should take into account recent research on the full scope and potential magnitude of mercury-related impacts. (C-24) The residual risk analysis methodology underestimates non-cancer risks associated with dietary exposure to mercury through fish for most-exposed populations. Recent research using state-of-the-science atmospheric and aquatic modelling suggests that fish-dependent communities may be exposed to levels exceeding EPA’s reference dose—even with policies like MATS in place. The multi-pathway exposure and risk screening assessment described in the Proposed Finding, and based on the National Emissions Standards for Hazardous Air Pollutants: Benzene Emissions from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP), may not be appropriate for methylmercury risk assessment. The assessment focuses on local (<50 km) impacts of single-facilities, rather than aggregate and cumulative effects of multiple facilities over regional scales. Mercury is indeed a local pollutant—the importance of US EGUs as a source of domestic deposition may in fact be underestimated in the RIA (Zhou et al. 2017; Sunderland et al. 2016). However, due to its different chemical forms, mercury also has regional impacts. As a result, regions with a high density of facilities that may be below the Tier 1 screening threshold emission rate, may still experience substantial mercury inputs. Further, the complex dynamics of mercury in aquatic and terrestrial ecosystems mean that some landscapes are more sensitive to mercury inputs than others (Perlinger et al. 2018). These dynamics are not captured in the exposure and risk screening assessment used by the EPA. Assessment methods that better capture the complex biogeochemistry of mercury indicate that highly- exposed populations (such as subsistence fishers and Tribal Nations where harvesting fish is an important dietary, socio-cultural, and rights-based practice) may be exposed to methylmercury at levels exceeding EPA’s reference dose, even with policies like MATS in place. In Perlinger et al. (2018), with colleagues, we model changes in atmospheric deposition and fish mercury concentrations in the Great Lakes resulting from policies at multiple jurisdictional scales (including MATS). We explore the environmental justice implications of these policy changes for a tribe in Michigan’s Upper Peninsula (UP) with a high fish consumption rate, the Keweenaw Bay Indian Community (KBIC). We find that even with regional, domestic, and global policy, KBIC members may be exposed to levels above the EPA reference dose at their desired level of fish consumption (454 g/day).1 The UP landscape is highly sensitive to Hg deposition, with nearly 80% of lakes estimated to be impaired. Sensitivity to mercury is caused primarily by the region's abundant wetlands. This finding suggests that landscape factors should be considered in the risk assessment process. Assessment methodologies such as the one described in the Proposed Finding also do not take into account legacy emissions (i.e., recycling of previously deposited mercury), and therefore underestimate health risks (Angot et al. 2018). Because it is persistent in the environment, mercury once emitted can circulate for decades to centuries. In Angot et al. (2018), with colleagues, using an integrated modelling approach, we quantify the impact of growing legacy reservoirs of mercury and find that due to this legacy penalty, aggressive maximum feasible reductions in emissions are needed for fish mercury concentrations to approach target levels by 2050 for high fish-consuming communities such as the Aroostook Band of Micmacs. 1 Research suggests that there is no threshold level of methylmercury exposure below which neurodevelopmental effects do not occur—consequently, the EPA reference dose is a non-conservative benchmark for health risk. In closing, we urge that the EPA consider up-to-date information in both its appropriate and necessary finding, and its assessment of residual risk. Respectfully, Amanda Giang Assistant Professor of Environmental Modelling and Policy Institute for Resources, Environment and Sustainability Department of Mechanical Engineering University of British Columbia Noelle Selin Associate Professor Institute for Data, Systems and Society and Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology With signatories: Hélène Angot Research Associate Institute of Arctic and Alpine Research University of Colorado, Boulder Hugh Gorman Professor of Environmental History and Policy Department of Social Sciences Michigan Technological University Noel Urban Professor of Environmental Engineering Department of Civil and Environmental Engineering Michigan Technological University Valoree S. Gagnon Director, University-Indigenous Community Partnerships Great Lakes Research Center Michigan Technological University Judith Perlinger Professor Civil & Environmental Engineering Department Michigan Technological University [Attachments: Giang & Selin 2016; Perlinger et al. 2018; Angot et al. 2018] Works Cited Angot, Hélène, Nicholas Hoffman, Amanda Giang, Colin P. Thackray, Ashley N. Hendricks, Noel R. Urban, and Noelle E. Selin. 2018. “Global and Local Impacts of Delayed Mercury Mitigation Efforts.” Environmental Science & Technology 52 (22): 12968–77. https://doi.org/10.1021/acs.est.8b04542. Genchi, Giuseppe, Maria Stefania Sinicropi, Alessia Carocci, Graziantonio Lauria,

Load more