ABSTRACT
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?ABSTRACT
On January 25, 2018, the United States Environmental Protection Agency withdrew a 1995 policy that mandates the use of maximum achievable control technology (MACT) to regulate emissions from major sources of hazardous air pollutants (HAPs), a category of toxic chemicals that may be carcinogenic, mutagenic, or cause other adverse health effects. To better understand the implications and scope of the change in regulatory guidance for HAP emissions of major sources that may reclassify as area sources, the increase in emissions that could legally occur under the new policy is assessed here. Based on facility-level data from a 2014 HAP national emissions inventory, it is estimated that 70% of major sources of HAPs qualify for reclassification as area sources, which could result in a maximum of 35,030 tons per year (tpy) of additional HAP emissions if all sources successfully reclassified. This amount would nearly triple the total volume of HAPs that qualifying major sources emitted in 2014. On average, qualifying sources could emit individually an additional 18.4 tpy. In the 21 states and territories that follow only federal guidelines for controlling HAPs, it is more likely that the estimates presented here could materialize compared to states that have additional guidelines for area sources of HAPs. The quantitative analysis of the potential emission changes resulting from regulatory change is instructive for industry, state and federal decisionmakers, and interested members of the public looking to understand and anticipate how relevant stakeholders will be affected by this policy change.
Implications: Withdrawal of a U.S. Environmental Protection Agency policy that mandates the use of maximum achievable control technology (MACT) to regulate emissions from major sources of hazardous air pollutants (HAPs) could result in higher emissions of toxic chemicals that may be carcinogenic, mutagenic, or cause other adverse health effects. Analysis of potential emission changes resulting from regulatory change is instructive for industry, state, and federal decisionmakers, and interested members of the public looking to understand and anticipate how relevant stakeholders will be affected by this policy change.
Introduction
Detrimental health outcomes as a result of exposure to air pollution are a major area of environmental and public health concern. Hazardous air pollutants (HAPs) are a class of 187 ambient air pollutants known to cause cancer and other serious health effects (Environmental Protection Agency 2020). Non-cancer adverse health effects from exposure to HAPs range from nausea and headaches to respiratory failure and death and depend on the magnitude and duration of exposure as well on the toxicity of individual HAPs (Environmental Protection Agency n.d.a.).
In the United States (U.S.), the Clean Air Act (CAA) directs the U.S. Environmental Protection Agency (USEPA) to protect public health and welfare by controlling industrial emissions and regulating ambient air quality (101st Congress 1990). The CAA established standards for six pollutants designated as criteria air pollutants (carbon monoxide, lead, particulate matter, ozone, nitrogen dioxide, and sulfur dioxide); however, there are no ambient air quality standards for HAPs (Michanowicz et al. 2013).
Instead, USEPA regulates HAPs by setting threshold levels of toxic emissions to classify industrial facilities as either “area sources” (those that emit or have the potential to emit below the thresholds) or “major sources” (those that emit or have the potential to emit above the thresholds). The threshold levels are 10 tons per year (tpy) for any one pollutant in the list of HAPs (101st Congress 1990) or 25 tpy of all pollutants emitted by a facility (hereafter “10/25 threshold”). In 1995, USEPA issued guidance known as “once in, always in” (OIAI) to control major source emissions of HAPs. Major sources are typically large facilities such as petrochemical manufacturers, metallurgical foundries, and power plants. Area sources are typically much smaller operations such as auto repair shops or dry cleaners. Major sources were required by the OIAI regulation to implement stringent pollution controls known as Maximum Achievable Control Technology (MACT). MACT provisions depend on specific HAPs and industrial processes but typically include the following: work practices such as tune-ups, inspections, assessments, and operation methods; process adjustments; equipment modification or replacement; capture and treatment of emitted pollutants; emission or operation monitoring devices and/or systems; and extensive recordkeeping and reporting to ensure compliance with requirements (Solutio Environmental 2018). The use of MACT has allowed many facilities to reduce their emissions well below the original classification thresholds (Seitz 1995) and, when fully implemented, it is estimated that the application of MACT to major sources of HAPs could reduce toxic emissions in the U.S. by 1.7 million tpy (Environmental Protection Agency 2018b).
On 25 January 2018, USEPA withdrew the OIAI policy by issuing new guidance that allows a major source to apply for reclassification as an area source if their HAPs emissions fall below the 10/25 thresholds (Wehrum 2018). Unlike the OIAI, which required any major source facility to always employ MACT to reduce future HAPs emissions, the new guidance could allow a situation known as “backsliding”. Backsliding could occur if a major source facility that has been successful in reducing emissions, is then reclassified as an area source, phases out its use of MACT, and then increases their HAP emissions to levels higher than the 10/25 thresholds. There is some evidence to suggest that this situation has the potential of occurring. First, USEPA has stated that major sources reclassified as area sources will not be subject to MACT requirements, thus allowing for the discontinuation of MACT controls. (Wehrum 2018). The EPA’s own 2019 Regulatory Impact Assessment (RIA) found that the 2018 guidance “may potentially result in both emission reductions and increases from a broad array of existing sources,” including HAP emissions (Sorrels 2019). Finally, industry has been exploring emissions options under the new policy that may include emissions increases (ERM & Bracewell 2018). And if backsliding were to occur, it may be difficult to verify that it is occurring if MACT monitoring, recordkeeping, and reporting requirements are phased out. It is also unclear how the new regulatory landscape would address a facility that increased its HAP emissions above the 10/25 threshold after being reclassified as an area source.
Considering the uncertainties in potential increases in HAP emissions from the elimination of the OIAI policy and MACT requirements, it is constructive to assess the potential for facilities to increase their HAP emissions under the new guidance. While it is unlikely that all eligible facilities will reclassify as area sources and increase their HAP emissions to the maximum allowance, estimated potential increases in HAP emissions from major sources that successfully reclassify to area sources and their likelihood given the new state and federal regulatory landscape are presented here as an exercise in demonstrating the full extent of the quantity, toxicity, and spatial distribution of potential increases in HAP emissions that could result from the 2018 guidance withdrawing the USEPA OIAI policy. This assessment was conducted by first developing an inventory of major sources subject to MACT that qualify for reclassification to area sources under the new policy, and then estimating their potential HAP emissions increase. Finally, the likelihood of potential emission increases is estimated by considering differences in U.S. state regulation of HAP emissions from area sources beyond CAA requirements.
Data and methods
Identification of MACT facilities and HAP emissions
Major source facilities subject to MACT were identified by obtaining facility-level reports from the USEPA Integrated Compliance Information System for Air (ICIS-AIR) reporting website (ICIS-AIR, Environmental Protection Agency 2018a), which contains information on the regulatory programs with which sources of ambient air pollution must comply. To link HAP emissions from these sources, the facilities found in ICIS-AIR were cross-referenced with the 2014 National Emissions Inventory (NEI, United States Environmental Protection Agency 2018c). Using the multiple identifiers assigned by USEPA ambient air programs (Toxics Release Inventory [TRI], Facilities Registry System [FRS], MACT, Emissions Inventory System [EIS], and the state/tribal/local jurisdiction air program identifier), major sources subject to MACT from ICIS-AIR were matched to HAP emissions from the NEI, excluding non-HAP emissions.
Estimation of potential emissions increases from major sources backsliding into area sources
Under the OIAI policy, USEPA required major sources to use MACT to reduce toxic emissions, even if, once in operation, that source could show it could reduce its potential to emit below 10/25 tpy using non-MACT controls. Under the OIAI withdrawal, a major source can petition USEPA to be reclassified as an area source if the source can demonstrate potential to emit emissions below the 10/25 tpy threshold. Accurately estimating facility-level annual potential to emit requires information on fuel types, emissions rates, hours of operation, operating temperatures, stack heights, and other parameters that are not consistently available for the major sources subject to MACT identified. Thus, actual HAP emissions reported to the NEI were used as a proxy for potential to emit. Potential to emit represents the upper limits that a facility’s equipment is designed to emit (Environmental Protection Agency 1998); thus, the estimates presented here are expected to be conservative, since it is likely that a facility’s potential to emit exceeds its actual reported emissions. The potential increase in annual HAP emissions for major sources that qualify for reclassification to area sources is represented as the maximum potential increase from actual on-site reported HAPs to the maximum allowable HAP emissions an area source could emit while complying with the National Emissions Standards for Hazardous Air Pollutants (NESHAP, Environmental Protection Agency n.d.b.) and USEPA area source 10/25 threshold. This approach was chosen because it represents a source’s potential emissions if the source reclassified from a major to area source and subsequently discontinued employment of MACT. Under the assumption that emissions from sources that have achieved reductions through MACT below the 10/25 thresholds were to discontinue use of MACT and potentially increase emissions up to 10/25 tpy, then subtracting actual tpy from 10/25 tpy would yield the potential increase in emissions that a source could emit before becoming subject to MACT again. This metric is termed here “potential backslide emissions increase” (PBEI, Equation (1)). 
(1)
(1)
where PBEIi is the potential backslide emissions increase for the i-th facility,
the constant 25 is the tons per year threshold for all HAPs emitted by a facility,
k is the number of individual HAPs reported by the i-th facility to the 2014 NEI, and
is the total HAP emissions, in tonsper year, reported by the i-th facility to the 2014 NEI.
In this research, PBEI was calculated only relative to the 25 tpy threshold as the more practical estimate, since calculating PBEI relative to the 10 tpy threshold would need to be done for each HAP emitted by a source. PBEI was calculated only for major sources that qualify for reclassification under the 25 tpy threshold, that is, facilities with total 2014 HAP emissions of 25 or less tpy. For example, say that a hypothetical Facility A reported to the NEI a total of 20 tpy for all HAPs. Facility A’s reported tpy falls below the 25 tpy threshold for all HAPs and is thus eligible for reclassification. Facility A’s PBEI would be 5 tpy because that is how much more HAP emissions Facility A could emit before reaching the 25 tpy threshold. Facilities that reported total HAP emissions above 25 tpy are not eligible for reclassification and were thus not included in the PBEI estimates. PBEI could vary widely in states and will depend on how states regulate HAPs from area sources. Some states follow the federal NESHAP, while others look at air pollution permits on a case-by-case basis. Sometimes states apply MACT for area sources, while others apply BACT (Best-Available Control Technology) or GACT (Generally Available Control Technology) standards for all area sources. New Source Performance Standards (NSPS) are mostly GACT, and most states implement GACT for area sources. NESHAPs for area sources typically represent a combination of BACT and GACT. In order to understand the likelihood that a state’s HAP area source rules would allow PBEI to materialize, individual states’ environmental protection agencies were contacted and asked if states follow NESHAP or if states have developed additional guidance. States were then categorized as either having additional guidance or only following federal guidelines for HAPs. Processing of ICIS-AIR and NEI 2014 data, including calculations of PBEI, were done using the R statistical analysis system (R Core Team 2017). Mapping was done in ArcGIS 10.3 (ESRI 2011). Finally, the 10 HAPs with the largest emissions amounts reported to the 2014 NEI.
Results
Potential backslide emissions increases (PBEI)
Out of the 3,418 major sources subject to MACT identified, HAP emissions were linked to 2,766 facilities (81.0%). These 2,766 facilities emitted 141,361 tons per year of HAPs in 2014. Seventy percent (1,926) of major sources emitted 25 or less tpy of all HAPs – thus qualifying for reclassification – and accounted for 9.1% (12,800 tpy) of all 2014 HAP emissions from major sources. The remaining 30.0% of facilities (840) accounted for 89.9% (128,561 tpy) of all 2014 HAP emissions from major sources. We calculated PBEI only for the 1,926 major sources that qualify for reclassification to area sources. PBEI estimates are shown in Figure 1.
Published online:
13 April 2020Figure 1. Potential backslide emissions increase of major sources of HAPs that qualify for reclassification from major to area sources under the withdrawal of the OIAI policy.
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Figure 1. Potential backslide emissions increase of major sources of HAPs that qualify for reclassification from major to area sources under the withdrawal of the OIAI policy.
It is estimated that if all qualifying major sources were reclassified to area sources, they could emit an additional 35,030 tpy of HAPs, which nearly triples the total air toxics that qualifying sources emitted in 2014 (12,800 tpy). On average, each qualifying source could increase HAP emissions by 18.4 tpy. States in the top 25% of PBEI estimates are, in decreasing PBEI ranking, Texas, Indiana, Ohio, Pennsylvania, North Carolina, Iowa, Alabama, Louisiana, Wisconsin, Kentucky, Michigan, and South Carolina. The top 10 individual HAPs from major sources by emissions volume account for 69,169 tpy, nearly half of all HAPs emitted by MACT facilities in 2014 (Table 1). The manufacturing sector (facilities in, for example, manufacture of chemicals and pharmaceuticals, petroleum refineries, and metallurgical foundries) accounts for nearly 85% of toxic emissions among major sources that qualify for reclassification (Table 2).
Table 1. Top 10 HAPs by emissions volume from major sources and their toxicity.
Table 2. Potential backslide emissions increases (PBEI) by sector.
Likelihood of PBEI estimates
Regulation by states of HAPs for area sources was queried for all 50 states and the territory of Puerto Rico. Other U.S. territories did not have facilities that would be impacted by the policy change and were not included in this analysis. No information could be obtained for Rhode Island, Vermont, Wisconsin, and Wyoming. States were grouped into one of two categories: states that only follow federal HAP guidelines by implementing NESHAP by reference into their State Implementation Plan process (20 states plus Puerto Rico for a total of 21 entities, Figure 2a), and states that have developed additional guidance and controls for HAP emissions from area sources (25 states, Figure 2b). In each bar in Figure 2, facilities are grouped using the same tpy classification scheme as in Figure 1. States with additional guidance vary widely in HAP regulations: some evaluate HAP limits for area source permits on a case-by-case basis, sometimes requiring MACT, while others require BACT or GACT (Environmental Protection Agency 1978) standards for all area sources (Environmental Protection Agency 1978). In the 21 states and territories that only follow federal guidelines, it is more likely that PBEI estimates could materialize. However, this does not imply that the 25 states with additional HAPs guidance could not experience toxic emissions increases; instead, the multiple ways in which those states regulate HAPs from area sources introduce more uncertainty in the potential for any particular source to increase HAP emissions. Potential increases permissible under the new guidance are, in most states, much larger than current total HAP emissions (Supplementary Figure 1).
Published online:
13 April 2020Figure 2. (a) Frequency of major sources of HAPs that qualify for reclassification stratified by potential backslide emissions increase in states that only follow federal HAPs guidelines. (b) Frequency of major sources of HAPs that qualify for reclassification stratified by potential backslide emissions increase in states that have additional HAPs guidelines.
![]({"type":"image","src":"/na101/home/literatum/publisher/tandf/journals/content/uawm20/2020/uawm20.v070.i05/10962247.2020.1735575/20200512/images/medium/uawm_a_1735575_f0002_c.jpg"})
Figure 2. (a) Frequency of major sources of HAPs that qualify for reclassification stratified by potential backslide emissions increase in states that only follow federal HAPs guidelines. (b) Frequency of major sources of HAPs that qualify for reclassification stratified by potential backslide emissions increase in states that have additional HAPs guidelines.
Discussion
In this research, the potential for HAP emissions increases from major sources following USEPA’s elimination of the OIAI policy and MACT requirements is assessed. This analysis estimates worst-case scenario emissions increases under the assumption that all major sources of HAPs eligible for reclassification do reclassify to area sources and increase HAP emissions up to the 25 tpy threshold. The scenario presented here is useful since USEPA has offered no guidance on reporting and monitoring requirements for major sources that successfully reclassify to area sources, or how the new guidance will prevent major sources that reclassify from emitting up to or beyond the 10/25 tpy threshold. In state jurisdictions, the regulatory framework for area source HAPs is not uniform. Consequently, there is much uncertainty about how this new interpretation of the law will work in practice, and the impacts on public health remain to be addressed and understood. However, it should be noted that USEPA’s 2019 RIA of the policy change found that many facilities in multiple source categories are likely to reclassify as area sources but that the changes in emissions and resulting changes in health effects are largely unknown (Sorrels 2019). It is unlikely that all eligible sources will successfully reclassify and increase their emissions to the maximum HAP thresholds, as companies have already invested in control technology, and the economic incentives of reclassification may not be sufficient to increase operations in a way that leads to increases in HAP emissions. Though actual HAP emissions increases will also depend on how states regulate HAPs from area sources, any toxic emissions increases have the potential to increase cancer and other adverse health risks in states where major sources successfully reclassify to area sources and increase HAP emissions.
Reducing HAP exposure – especially for populations living near HAP sources – can help reduce adverse health outcomes from toxic emissions. Several studies have suggested that residential proximity to a HAP-emitting facility is correlated with HAP exposure (Benin et al. 1999; Gilbert and Viau 1997). Higher incident rates of cancers in children (Reynolds et al. 2003; Thompson, Carozza, and Zhu 2008) and adults (Chakraborty 2012) have been observed in counties and census tracts with higher levels of HAP emissions from industrial sources. For three neighboring census tracts in Pittsburgh, Pennsylvania, 245 of the 289 per million predicted lifetime cancer cases in the area were attributable to industrial point sources, of which 138 per million cancer cases were attributable to HAP emissions from coke facilities (Michanowicz et al. 2013). It is also worrisome that HAP sources tend to be located near communities with higher proportions of low-income individuals and people of color, raising environmental justice concerns around exposure to HAPs (Chakraborty 2012; Linder, Marko, and Sexton 2008). Rates of African-Americans, Hispanics, persons living in poverty, and other markers of social disadvantage are significantly higher among residential zones with nearby facilities that store or use hazardous chemicals (Bullard, Johnson, and Torres 2011; Cushing et al. 2015; Orum et al. 2014; Starbuck and White 2016). In Tampa, Florida, a 10% increase in the African American or Hispanic American population has been correlated to an increased cancer risk of 5.4% or 10.2%, respectively. In Houston, Texas, the cancer risk burden increased as the proportion of residents who are Hispanic increased and also along key indicators of relative social disadvantage (Chakraborty 2012; Linder, Marko, and Sexton 2008). Emerging research has also linked lesbian, gay, bisexual, and transgender (LGBT) populations to higher HAP-attributable cancer and respiratory risks (Collins, Grineski, and Morales 2017). Although many of the HAP risks faced by disadvantaged populations are chronic, large clusters of facilities that process or store dangerous chemicals also pose acute risks from explosions, fires, or other accidental events that release large volumes of toxics in short amounts of time, effectively burdening communities with the “double jeopardy” of chronic and acute toxic risks (Union of Concerned Scientists 2016). Weakening of science-based ambient air quality standards and emissions control regulations may result in increased impacts in communities that are already overburdened with disproportionate impacts of air pollution from proximity to industrial and mobile sources (Chakraborty 2012; Morello-Frosch et al. 2011).
In eliminating the OIAI policy and MACT, USEPA has argued that compliance with MACT is burdensome and expensive, and that USEPA did not have authority under the CAA to create the policy, effectively curtailing its own ability to regulate HAPs and weakening the agency’s ability to protect public health from HAP exposure, as mandated in the CAA (as argued in Freeman 2017). However, the costs of compliance should be weighed against, for example, USEPA’s own 2011 finding that application of MACT (for mercury reductions from coal and oil-fired electric generating units) can result in significant benefits largely attributable to decreased premature deaths as well as reducing the detrimental health impacts of HAPs – benefits that outweigh the costs of compliance (Environmental Protection Agency 2011a; see also Sunderland et al. 2016 for a discussion of benefits).
Notwithstanding the move toward similar deregulatory actions of CAA policies that have occurred or been proposed in recent years (Goldman and Dominici 2019; Goldman, Reed, and Carter 2017), MACT standards have proven to be an effective tool for encouraging the development of new technology that can be economically efficient in reducing HAP emissions. For instance, when USEPA set a MACT standard for mercury emission levels for sewage sludge incinerators in 2016, industry groups in Ohio adopted mercury removal technology that had performed well in pilot studies. MACT compliance testing performed well in some mercury reduction emissions scenarios (where reductions occurred, these ranged between 80 and 95 percent of allowable mercury emissions for sewage sludge) and allowed the industry group to save $15-20 million as compared to the alternate MACT available. The use of the technology spread to facilities in other states and appeared to be effective at reducing mercury over a one-year time period (Smith et al. 2017).
There are some limitations to the analysis presented here. Matching major sources of HAPs from USEPA ICIS-AIR based on facility identifiers in the NEI could have introduced mismatched emissions volumes. Due to the large number of facilities, it was not practicable to manually verify if each facility was correctly matched. The only other systematic assessment of HAP emissions in the U.S. is in the USEPA 2019 RIA. But the RIA does not report on the total number of major sources of HAPs in their analysis, instead grouping their cost-saving estimates in sources above, and separately, below the 10/25 tpy thresholds, so a comparison of the number of major sources is not possible.
The analysis did not consider the dispersion of HAPs through ambient air or other media, focusing instead on assessing reported HAP emissions as emitted from major sources. An assessment of fate and transport of HAPs is beyond the scope of this study, as is an analysis of human health risks in communities exposed to the increased HAP emissions estimates presented here; both the fate and transport, and human health risks remain an important area of future research given the potential HAP increase estimates from USEPA’s elimination of the OIAI policy and MACT requirements. The National Air Toxics Assessment (NATA, Environmental Protection Agency 2015) represents the state of the science of HAP atmospheric dispersion modeling, as well as estimates of cancer risks and non-cancer hazards from exposure to most HAPs. The NATA suite of tools and maps could be a useful starting point to understand existing cancer and non-cancer risks from HAPs exposure in communities hosting the 1,926 major sources of HAPs eligible for reclassification presented here and could also serve as a baseline to estimate additional health risks from increased HAP emissions. This is critical in order to understand public health risks associated with the elimination of the OIAI policy and MACT, underscored by the fact that the USEPA 2019 RIA does not incorporate NATA nor potential public health impacts in its assessment of emissions increases from the policy change.
There are also uncertainties around HAP emissions reported to the NEI used to derive PBEI in this research. An accuracy assessment of national emissions inventories of HAPs in the U.S. estimates that confidence levels are low, low-medium, or medium (Miller et al. 2006). For other toxic inventories besides those in the NEI, de Marchi, Scott, and Hamilton (2006) have assessed the role of flexibility in self-reporting of emissions in the U.S. regulatory framework, concluding that there is large variability in methods for estimating emissions which can account for substantial discrepancies between monitored concentrations and self-reported emissions in the Toxics Release Inventory. Furthermore, the 2014 NEI used in this research does not include a quantitative accuracy assessment at any level of aggregation (e.g. facility, industrial sector, or geographical aggregation unit). It follows, then, that the lack of a comprehensive accuracy assessment for HAP emissions in the NEI is one source of uncertainty in this research because PBEI estimates are based on 2014 HAP emissions – any errors in reported HAP emissions will propagate to PBEI estimates. The lack of consolidated HAP emissions inventory requirements by USEPA, however, predates the OIAI policy, and is a long-standing problem in implementation of the CAA. The second source of uncertainty comes from the assumption that all major sources of HAPs eligible for reclassification do reclassify to area sources and increase HAP emissions up to the 25 tpy threshold. While this assumption is not likely, the purpose of the analysis presented here is not to demonstrate how much more HAP emissions are probable, but instead to look at the range of emission increases that are now potentially allowable under the new guidance, which are inclusive of – but not limited to – the worst-case scenario where all eligible major sources of HAPs reclassify to area source. If the monitoring, reporting, and enforcement requirements for major sources of HAPs are eliminated under area source rules, the public and USEPA may have less access to information on whether a source’s actual emissions or potential to emit have reached the major source thresholds that would require an area source to be reclassified as a major source. Furthermore, there is added uncertainty about potential toxic emissions increases because states regulate area sources very differently than the way USEPA regulates major sources. Since the 2018 guidance does not address these potential issues, additional regulatory guidance is needed to fully characterize the magnitude and location of potential toxic air emissions increases and public health outcomes, especially on environmental justice populations. In addition, the new guidance’s impact may not be limited to HAPs, as direct emissions or atmospheric formation of criteria air pollutants (CAP) such as volatile organic compounds (VOCs), small particulates (PM2.5), sulfur dioxide (SO2), and nitrous oxides (NO2) – as stated in the USEPA 2019 RIA – may be affected by the rule change (Sorrels 2019). The RIA’s analysis of potential HAP emission changes in selected industries from the rule change anticipates that few HAP emissions increases will occur and that unspecified “non-HAP regulatory requirements that also provide for HAP control” will prevent increases (Sorrels 2019, 4–7). On the first point, it should be noted that continuing compliance of HAP standards is ensured by recordkeeping, monitoring, and reporting requirements (Laznow and Daniel 1992), but since the RIA has found significant economic cost reductions to industry due to the elimination of labor costs associated with eliminating recordkeeping, monitoring, and reporting activities, it is not clear which mechanisms will be available to state regulatory authorities to ensure compliance.
In light of the uncertainties around available regulatory HAP emissions data and the lack of guidance by USEPA, it is informative to understand the impacts that industry, state governments, environmental groups, and other stakeholders anticipate from the elimination of the OIAI policy and MACT. Before closing of the comments period of the final rulemaking process in September 2019, more than 16,000 comments were submitted to the USEPA docket on the rule change (EPA 2019). Though a comprehensive assessment of the large amount of comments is beyond the scope of this research, a few insights emerge from reading through some of them. Industry groups largely welcome the change, claiming that OIAI disincentivized sources from implementing voluntary pollution abatement or technological innovation to reduce HAP emissions, and that sources were unfairly regulated based on historical – as opposed to current – HAP emission levels. One industry group called OIAI a “lifetime punitive sentence on affected businesses that may never have exceeded [HAP] emission limitations” (National Small Business Environmental Assistance Programs 2019). Other industry stakeholders noted that complex recordkeeping requirements and annual certification processes created competitive disadvantages now eliminated following rescinding of the policy. On the other hand, environmental and tribal groups, as well as some former USEPA employees and some state regulators, oppose the rule change, warning, for example, that: public and environmental health will be negatively impacted by HAP emissions increases; USEPA has not fully assessed the legality and enforceability of the rule change and has made unsupported assumptions not based on comprehensive analyses; the rule change goes against the congressional intent of the CAA; the rule change will create an unfunded mandate to state regulators. In addition, opponents of the rule change are worried that phasing out HAP monitoring and reporting requirements will deprive communities from accessing such information, and that USEPA has not followed federal requirements to consider environmental justice. Finally, opponents lament one key provision of the rule change: the removal of the federal enforceability of the potential to emit because – they claim – enforcement is necessary to assure maintenance of emission reductions.
The quantitative analysis presented here of the potential emission changes resulting from the MACT regulatory change is instructive for industry, state, and federal decisionmakers, and interested members of the public looking to understand and anticipate how relevant stakeholders could be affected by this policy change. Conducting such analyses can encourage lawmakers and regulators to enact health-protective policies as preventative measures against potential emissions increases such as those assessed here.
| Hazardous Air Pollutant | Total 2014 Emissions (tpy) | Reference Concentration (milligrams/cubic meter)* |
|---|---|---|
| Hydrochloric Acid | 38,084 | 2.00E-02 |
| n-Hexane | 12,743 | 7.00E-01 |
| Styrene | 8,022 | 2.00E-02 |
| Xylene and Mixed Isomers | 4,466 | 1.00E-01 |
| Chlorine | 2,325 | 1.50E-04 |
| Benzene | 1,910 | 3.00E-02 |
| Chloromethane | 644 | 9.00E-02 |
| Naphtalene | 398 | 3.00E-03 |
| Manganese Compounds | 314 | 5.00E-05 |
| 1-3-Butadiene | 264 | 2.00E-03 |
| Data sources: EPA 2018, 2010 | ||
Notes.* “An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime” (EPA n.d.a.)
| NAICS* Sector | Number of facilities | Total PBEI* (tpy) | Mean PBEI* (tpy/facility) | Percent of Total PBEI* |
|---|---|---|---|---|
| Manufacturing | 1651 | 29,967.2 | 18.2 | 84.8 |
| Utilities | 120 | 1977.8 | 16.5 | 5.6 |
| Wholesale Trade | 50 | 1139.1 | 22.8 | 3.2 |
| Public Administration | 32 | 626.7 | 19.6 | 1.8 |
| Transportation and Warehousing | 19 | 427.9 | 22.5 | 1.2 |
| Administrative Support; Waste Management and Remediation Services | 16 | 359.9 | 22.5 | 1.0 |
| Mining | 14 | 306.6 | 21.9 | 0.9 |
| Retail Trade | 13 | 291.0 | 22.4 | 0.8 |
| Professional, Scientific, and Technical Services | 5 | 116.2 | 23.2 | 0.3 |
| Other Services (except Public Adminsitration) | 3 | 64.3 | 21.4 | 0.2 |
| Agriculture, Forestry, Fishing, and Hunting | 1 | 25.0 | 25.0 | 0.1 |
| Health Care and Social Assistance | 1 | 25.0 | 25.0 | 0.1 |
| Construction | 1 | 23.5 | 23.5 | 0.1 |
Notes. *: North American Industry Classification System.
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