Repository for Oil and Gas Energy Research (ROGER)

Abstract:
Oil and gas extraction-related activities produce air and water pollution that contains known and suspected teratogens. To date, health impacts of in utero exposure to these activities is largely unknown.

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Spills of hydraulic fracturing (HF) fluids and of produced water during unconventional gas extraction operations may cause soil contamination. We studied the degradation and microbial toxicity of selected HF chemical components including two biocides (methylisothiozolinone- MIT, chloromethylisothiozolinone- CMIT), a gel-breaker aid (triethanolamine -TEA), and three geogenic chemicals (phenol, m-cresol and p-cresol) in ultrapure water, HF fluid and produced water in five different soil types (surface and subsurface soils). The degradation of the two biocides (in soils treated with HF fluid or ultrapure water) and of the three geogenic chemicals (in soils treated with produced water) was rapid (in all cases DT50 values < 2 days in surface soils). In contrast, the loss of TEA was much slower in soils, especially in those treated with HF fluid (DT50 > 30 days). Sorption coefficients (Koc in L/Kg) in these soils ranged from 71 to 733 for TEA, 64–408 for MIT and 11–72 for CMIT. In terms of soil microbial toxicity, exposure to HF fluid and produced water reduced microbial respiration, albeit temporarily. The overall microbial activities in surface soils contaminated with produced water had fully recovered in most soils. In contrast, the HF fluid addition to soils completely inhibited the nitrification in all soils, with little recovery over the 60 day experimental period. In the case of produced water exposure, three out of five surface soils showed complete recovery in nitrification during the study period. The functional genes for nitrogen fixation (nifH) and carbon cycling (GA1) and microbial community composition (16 S rRNA) were significantly affected by HF fluid in some soils. Overall, the study shows that the HF fluid can have significant detrimental impact on soil microbial functions, especially on nitrogen cycling. More work is needed to identify the exact cause of microbial toxicity in soils contaminated with HF fluid.

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Unconventional natural gas development (fracking) has been a rapidly expanding technique used for the extraction of natural gas from the Marcellus Shale formation in Pennsylvania. There remains a knowledge gap regarding the ecological impacts of fracking, especially regarding the long-term health of native Brook trout (Salvelinus fontinalis) populations. During the summer of 2015, Brook trout were sampled from twelve streams located in forested, northwestern Pennsylvania in order to evaluate the impacts of fracking on Brook trout. Four stream sites were undisturbed (no fracking activity), three had a developed well pad without fracking activity, and five had active fracking with natural gas production. Liver tissue was isolated from two to five fish per stream and underwent RNA-Seq analysis to identify differentially expressed genes between ecosystems with differing fracking status. Data were analyzed individually and with samples pooled within-stream to account for hierarchical data structure and variation in sample coverage within streams. Differentially expressed and differentially alternatively spliced genes had functions related to lipid and steroid metabolism, mRNA processing, RNA polymerase and protein regulation. Unique to our study, genes related to xenobiotic and stress responses were found as well as potential markers for endocrine disruption and saline adaptation that were identified in watersheds with active fracking activity. These results support the utility of RNA-Seq to assess trout health and suggest detrimental impacts of fracking on sensitive trout populations.

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Epidemiologic studies have observed elevated health risks in populations living near unconventional oil and gas development (UOGD). In this narrative review, we discuss strengths and limitations of UOG exposure assessment approaches used in or available for epidemiologic studies, emphasizing studies of children’s health outcomes.

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Since the early 2000s, unconventional natural gas development (UNGD) has rapidly grown throughout Pennsylvania. UNGD extracts natural gas using a relatively new method known as hydraulic fracturing (HF). Here we addressed the association of HF with asthma Hospitalization Admission Rates (HAR) using publicly available data. Using public county-level data from the Pennsylvania Department of Health (PA-DOH) and the Pennsylvania Department of Environmental Protection for the years 2001–2014, we constructed regression models to study the previously observed association between asthma exacerbation and HF. After considering multicollinearity, county-level demographics and area-level covariables were included to account for known asthma risk factors. We found a significant positive association between the asthma HAR and annual well density for all the counties in the state (3% increase in HAR attributable to HF, p<0.001). For a sensitivity analysis, we excluded urban counties (urban counties have higher asthma exacerbations) and focused on rural counties for the years 2005–2014 and found a significant association (3.31% increase in HAR attributable to HF in rural counties, p<0.001). An even stronger association was found between asthma hospitalization admission rates (HAR) and PM2.5 levels (7.52% increase in HAR attributable to PM2.5, p<0.001). As expected, asthma HAR was significantly higher in urban compared to rural counties and showed a significant racial disparity. We conclude that publicly available data at the county-level supports an association between an increase in asthma HAR and UNGD in rural counties in Pennsylvania.

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With growing evidence of widespread health and environmental impacts from oil and gas activity, localities and states are beginning to develop protective measures. Interdisciplinary approaches that integrate across human, wildlife, domesticated animal, and land health are likely to provide more just and comprehensive solutions than would be possible with siloed approaches. However, this is not common practice, and there is little guidance on how to apply such a strategy. In the present article, we summarize the state of knowledge on the impacts of terrestrial unconventional oil and gas development from the fields of ecology and public health. We then discuss synergies and trade-offs regarding impacts and mitigation strategies emerging from these two literatures. Finally, we provide recommendations for research and practice to fill knowledge gaps and better inform integrated decision-making to achieve multiple benefits and minimize impacts on human, wildlife, domesticated animals, and land health from energy development.

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Due to the growing hydraulic fracturing (HF) practices in China, the environmental risks of pollutants in flowback and produced waters (FPW) and sludge in impoundments for FPW reserves have drawn increasing attention. In this context, we first characterized the comparative geochemical characteristics of the FPW and the sludge in impoundments that collected FPW from 75 shale gas wells, and then the risks associated with the pollutants were assessed. The results demonstrated that four organic compounds detected in the FPW, naphthalene, acenaphthene, dibutyl phthalate, and bis(2-ethylhexyl)phthalate, were potential threats to surface waters. The concentrations of trace metals (copper, cadmium, manganese, chromium, nickel, zinc, arsenic, and lead) in the FPW and sludge were low; however, those of iron, barium, and strontium were high. The accumulation of chromium, nickel, zinc, and lead in the sludge became more evident as the depth increased. The environmental risks from heavy metals in the one-year precipitated sludge were comparable to those reported in the environment. However, the radium equivalent activities were 10–41 times higher than the recommended value for human health safety, indicating potential radiation risks. Although hydrophobic organic compounds, such as high-molecular-weight polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs), benzene, ethylbenzene, toluene, and xylene (BTEX), tended to accumulate in the sludge, their environmental risks were within tolerable ranges after proper treatment. Multiple antibiotic resistance genes (ARGs), such as those for macrolide, lincosamide, streptogramin (MLS), tetracycline, and multidrug resistances, were detected in the shale gas wastewaters and sludge. Therefore, the environmental risks of these emerging pollutants upon being discharged or leaked into surface waters require further attention.

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Little is known about whether exposure to unconventional oil and gas development is associated with higher mortality risks in the elderly and whether related air pollutants are exposure pathways. We studied a cohort of 15,198,496 Medicare beneficiaries (136,215,059 person-years) in all major US unconventional exploration regions from 2001 to 2015. We gathered data from records of more than 2.5 million oil and gas wells. For each beneficiary’s ZIP code of residence and year in the cohort, we calculated a proximity-based and a downwind-based pollutant exposure. We analysed the data using two methods: a Cox proportional hazards model and a difference-in-differences design. We found evidence of a statistically significant higher mortality risk associated with living in proximity to and downwind of unconventional oil and gas wells. Our results suggest that primary air pollutants sourced from unconventional oil and gas exploration can be a major exposure pathway with adverse health effects in the elderly.

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Background: Unconventional oil and gas development (UOGD) releases chemicals that have been linked to cancer and childhood leukemia. Studies of UOGD exposure and childhood leukemia are extremely limited. Objective: The objective of this study was to evaluate potential associations between residential proximity to UOGD and risk of acute lymphoblastic leukemia (ALL), the most common form of childhood leukemia, in a large regional sample using UOGD-specific metrics, including a novel metric to represent the water pathway. Methods: We conducted a registry-based case–control study of 405 children ages 2–7 y diagnosed with ALL in Pennsylvania between 2009–2017, and 2,080 controls matched on birth year. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between residential proximity to UOGD (including a new water pathway-specific proximity metric) and ALL in two exposure windows: a primary window (3 months preconception to 1 y prior to diagnosis/reference date) and a perinatal window (preconception to birth). Results: Children with at least one UOG well within 2km 2 km of their birth residence during the primary window had 1.98 times the odds of developing ALL in comparison with those with no UOG wells [95% confidence interval (CI): 1.06, 3.69]. Children with at least one vs. no UOG wells within 2km 2 km during the perinatal window had 2.80 times the odds of developing ALL (95% CI: 1.11, 7.05). These relationships were slightly attenuated after adjusting for maternal race and socio-economic status [odds ratio (OR) =1.74 = 1.74 (95% CI: 0.93, 3.27) and OR=2.35 OR = 2.35 (95% CI: 0.93, 5.95)], respectively). The ORs produced by models using the water pathway-specific metric were similar in magnitude to the aggregate metric. Discussion: Our study including a novel UOGD metric found UOGD to be a risk factor for childhood ALL. This work adds to mounting evidence of UOGD’s impacts on children’s health, providing additional support for limiting UOGD near residences. https://doi.org/10.1289/EHP11092

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Oil and gas extraction produces air pollutants that are associated with increased risks of hypertension. To date, no study has examined residential proximity to oil and gas extraction and hypertensive conditions during pregnancy. This study quantifies associations between residential proximity to oil and gas development on gestational hypertension and eclampsia.We utilized a population-based retrospective birth cohort in Texas (1996–2009), where mothers reside <10 km from an active or future drilling site (n = 2 845 144.) Using full-address data, we linked each maternal residence at delivery to assign exposure and evaluate this exposure with respect to gestational hypertension and eclampsia. In a difference-in-differences framework, we model the interaction between maternal health before (unexposed) or after (exposed) the start of drilling activity (exposed) and residential proximity near (0–1, >1–2 or >2–3 km) or far (≥3–10 km) from an active or future drilling site.Among pregnant women residing 0–1 km from an active oil or gas extraction site, we estimate 5% increased odds of gestational hypertension [95% confidence interval (CI): 1.00, 1.10] and 26% increased odds of eclampsia (95% CI: 1.05, 1.51) in adjusted models. This association dissipates in the 1- to 3-km buffer zones. In restricted models, we find elevated odds ratios among maternal ages ≤35 years at delivery, maternal non-Hispanic White race, ≥30 lbs gained during pregnancy, nulliparous mothers and maternal educational attainment beyond high school.Living within 1 km of an oil or gas extraction site during pregnancy is associated with increased odds of hypertensive conditions during pregnancy.

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Background:  Prenatal exposure to hydraulic fracturing (HF), a chemically intensive oil and gas extraction method, may be associated with adverse birth outcomes, but no health studies have been conducted in California. Methods:  We conducted a retrospective cohort study of 979,961 births to mothers in eight California counties with HF between 2006 and 2015. Exposed individuals had at least 1 well hydraulically fractured within 1 km of their residence during pregnancy; the reference population had no wells within 1 km, but at least one oil/gas well within 10 km. We examined associations between HF and low birth weight (LBW), preterm birth (PTB), small for gestational age birth (SGA), and term birth weight (tBW) using generalized estimating equations and assessing urban-rural effect modification in stratified models. Results:  Fewer than 1% of mothers (N = 1,192) were exposed to HF during pregnancy. Among rural mothers, HF exposure was associated with increased odds of LBW (odds ratio [OR] = 1.74; 95% confidence interval [CI] = 1.10, 2.75), SGA (OR = 1.68; 95% CI = 1.42, 2.27) and PTB (OR = 1.17; 95% CI = 0.64, 2.12), and lower tBW (mean difference: –73 g; 95% CI = –131, –15). Among urban mothers, HF exposure was positively associated with SGA (OR = 1.23; 95% CI = 0.98, 1.55), inversely associated with LBW (OR = 0.83; 95% CI = 0.63, 1.07) and PTB (OR = 0.65; 95% CI = 0.48, 0.87), and not associated with tBW (mean difference: –2 g; 95% CI = –35, 31). Conclusion:  HF proximity was associated with adverse birth outcomes, particularly among rural Californians.

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Background Northeastern British Columbia (Canada) is an area of unconventional natural gas (UNG) exploitation by hydraulic fracturing, which can release several contaminants, including volatile organic compounds (VOCs). To evaluate gestational exposure to contaminants in this region, we undertook the Exposures in the Peace River Valley (EXPERIVA) study. Objectives We aimed to: 1) measure VOCs in residential indoor air and tap water from EXPERIVA participants; 2) compare concentrations with those in the general population and explore differences related to sociodemographic and housing characteristics; and 3) determine associations between VOC concentrations and density/proximity to UNG wells. Methods Eighty-five pregnant women participated. Passive air samplers were analyzed for 47 VOCs, and tap water samples were analyzed for 44 VOCs. VOC concentrations were compared with those from the Canadian Health Measure Survey (CHMS). We assessed the association between different metrics of well density/proximity and indoor air and tap water VOC concentrations using multiple linear regression. Results 40 VOCs were detected in >50% of air samples, whereas only 4 VOCs were detected in >50% of water samples. We observed indoor air concentrations >95th percentile of CHMS in 10–60% of samples for several compounds (acetone, 2-methyl-2-propanol, chloroform, 1,4-dioxane, hexanal, m/p-xylene, o-xylene, styrene, decamethylcyclopentasiloxane, dodecane and decanal). Indoor air levels of chloroform and tap water levels of total trihalomethanes were higher in Indigenous participants compared to non-Indigenous participants. Indoor air levels of chloroform and acetone, and tap water levels of total trihalomethanes were positively associated with UNG wells density and proximity metrics. Indoor air BTEX (benzene, toluene, ethylbenzene, xylenes) levels were positively correlated with well density/proximity metrics. Conclusion Our results suggest higher exposure to certain VOCs in pregnant women living in an area of intense unconventional natural gas exploitation compared with the general Canadian population, and that well density/proximity is associated with increased exposure to certain VOCs.

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Oil and gas development has led to environmental hazards and community concerns, particularly in relation to water supply issues. Filing complaints with state agencies enables citizens to register concerns and seek investigations. We evaluated associations between county-level socio-economic and demographic factors, oil and gas drilling, and three outcomes in Pennsylvania between 2004 and 2016: number of oil and gas complaints filed, and both the number and proportion of state investigations of water supply complaints yielding a confirmed water supply impairment (i.e., “positive determination”). We used hierarchical Bayesian Poisson and binomial regression analyses. From 2004 to 2016, 9,404 oil and gas-related complaints were filed, of which 4,099 were water supply complaints. Of those, 3,906 received investigations, and 215 yielded positive determinations. We observed a 47% increase in complaints filed per $10,000 increase in annual median household income (MHI) (Rate Ratio [RR]: 1.47, 95% credible interval [CI]: 1.09–1.96) and an 18% increase per 1% increase in educational attainment (RR: 1.18, 95% CI: 1.11–1.26). While the number of complaints filed did not vary by race/ethnicity, the odds of a complaint yielding a positive determination were 0.81 times lower in counties with a higher proportion of marginalized populations (Odds Ratio [OR]: 0.81 per 1% increase in percent Black, Asian, and Native American populations combined, 95% CI: 0.64–0.99). The odds of positive determinations were also lower in areas with higher income (OR per $10,000 increase in MHI: 0.35, 95% CI: 0.09–0.96). Our results suggest these relationships are complex and may indicate potential environmental and procedural inequities, warranting further investigation.

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Diluted bitumen, also known as dilbit, is transported by rail and pipeline across Canada and the United States. Due to the fewer number of studies characterizing the toxicity of dilbit, a dilbit spill poses an unknown risk to freshwater aquatic ecosystems. In the following study, we compared the impact of early-life exposure to conventional and unconventional crude oils on the optomotor behavior, reproductive success, and transgenerational differences in gene expression in zebrafish and their progeny. For exposures, water accommodated fractions (WAFs) of crude oil were generated using a 1:1000 oil to water ratio for 3 different crudes; mixed sweet blend (MSB), medium sour composite (MSC) and dilbit. All three oils generated unique volatile organic compound (VOC) and polycyclic aromatic compound (PAC) profiles. Of the WAFs tested, only dilbit decreased the eye size of 2 dpf larvae, and only MSB exposed larvae had an altered behavioral response to a visual simulation of a predator. Early-life exposure to crude oil had no lasting impact on reproductive success of adult fish; however, each oil had unique impacts on the basal gene expression of the somatically exposed offspring. In this study, the biological effects differed between each of the oils tested, which implied chemical composition plays a critical role in determining the sublethal toxicity of conventional and unconventional crude oils in freshwater ecosystems.

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The expansion of unconventional oil and gas development (UNGD) in the US has been highly controversial so far with no consensus on its health, economic, environmental, and social implications. This paper examines the effects of UNGD on the health profile of the population in the context of Oklahoma using a unique data set. To this end, the analysis assembles a panel data set including 76 counties of Oklahoma, spanning the period 1998–2017. The analysis estimates the long-run relationship between the health profile and its determinants using the Common Correlated Effects (CCE) method. The empirical setup allows for cross-sectional dependence and accounts for both observed and unobserved heterogeneity. The main findings provide strong evidence that UNGD activities have negative effects on human health-related outcomes across all counties in Oklahoma. Specifically, an increase in the number of (unconventional) wells has a positive impact on mortality rates, and incidences of cancer, cardiac, and respiratory diseases in communities in close spatial proximity, and a negative impact on life expectancy. These findings provide evidence that UNGD activities pose significant risks to the public health profile across the Oklahoma population. Such findings are expected to have substantial implications for the national debate on the regulation of UNGD.

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Objectives To evaluate the long-term (psychosomatic) health consequences of man-made earthquakes compared with a non-exposure control group. Exposure was hypothesised to have an increasingly negative impact on health outcomes over time. Setting Large-scale gas extraction in the Netherlands causing earthquakes and considerable damage. Participants A representative sample of inhabitants randomly selected from municipal population records; contacted 5 times during 21 months (T1: N=3934; T5: N=2150; mean age: 56.54; 50% men; at T5, N=846 (39.3%) had no, 459 (21.3%) once and 736 (34.2%) repeated damages). Main measures (Psychosomatic) health outcomes: self-rated health and Mental Health Inventory (both: validated; Short Form Health Survey); stress related health symptoms (shortened version of previously validated symptoms list). Independent variable: exposure to the consequences of earthquakes assessed via physical (peak ground acceleration) and personal exposure (damage to housing: none, once, repeated). Results Exposure to induced earthquakes has negative health consequences especially for those whose homes were damaged repeatedly. Compared with a no-damage control group, repeated damage was associated with lower self-rated health (OR:1.64), mental health (OR:1.83) and more stress-related health symptoms (OR:2.52). Effects increased over time: in terms of relative risk, by T5, those whose homes had repeated damage were respectively 1.60 and 2.11 times more likely to report poor health and negative mental health and 2.84 times more at risk of elevated stress related health symptoms. Results for physical exposure were comparable. Conclusion This is the first study to provide evidence that induced earthquakes can have negative health consequences for inhabitants over time. It identifies the subpopulation particularly at risk: people with repeated damages who have experienced many earthquakes. Findings can have important implications for the prevention of negative health consequences of induced earthquakes.

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Migraine–an episodic disorder characterized by severe headache that can lead to disability–affects over 1 billion people worldwide. Prior studies have found that short-term exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone increases risk of migraine-related emergency department (ED) visits. Our objective was to characterize the association between long-term exposure to sources of harmful emissions and common air pollutants with both migraine headache and, among patients with migraine, headache severity.

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In 2010, twenty-eight bovines on a Pennsylvania beef farm were exposed to a hydraulic fracturing wastewater leak on their grazing pasture. Over the following year, eleven out of seventeen calves born to the exposed animals died. The farmers framed the deaths as outside normal deathly production on the farm, while state institutions claimed the deaths resulted from the farmers’ negligence, framing them as ordinary. I draw on necropolitics to examine how death becomes a normalized mode of capital production in agri-food systems, investigating how the wastewater spill and calves’ deaths ruptured the everyday production of bovine death. The paper argues that death must occur in prescribed sites and at approved times to function as a site of value accumulation in capitalist agriculture. I examine how the spill and calf death events emerged through promiscuous entanglements between overlapping modes of capital extraction across and through the site of the farm. Using assemblages, I trace unruly, promiscuous encounters at this food-energy contact zone to consider how the calves’ deaths render visible the space-time boundaries used to manage more-than-human mortality as a metabolic process in livestock production, and highlight disparate power relations between diverse necropolitical actors and modes of governance.

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Limited air monitoring studies with long-term measurements during all phases of development and production of natural gas and natural gas liquids have been conducted in close proximity to unconventional natural gas well pads.

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Background Whereas it is plausible that unconventional natural gas development (UNGD) may adversely affect cardiovascular health, little is currently known. We investigate whether UNGD is associated with acute myocardial infarction (AMI). Methods In this observational study leveraging the natural experiment generated by New York’s ban on hydraulic fracturing, we analyzed the relationship between age- and sex-specific county-level AMI hospitalization and mortality rates and three UNGD drilling measures. This longitudinal panel analysis compares Pennsylvania and New York counties on the Marcellus Shale observed over 2005-2014 (N=2,840 county-year-quarters). Results A hundred cumulative wells is associated with 0.26 more hospitalizations per 10,000 males 45-54y.o. (95% CI 0.07,0.46), 0.40 more hospitalizations per 10,000 males 65-74y.o. (95% CI 0.09,0.71), 0.47 more hospitalizations per 10,000 females 65-74y.o. (95% CI 0.18,0.77) and 1.11 more hospitalizations per 10,000 females 75y.o.+ (95% CI 0.39,1.82), translating into 1.4-2.8% increases. One additional well per square mile is associated with 2.63 more hospitalizations per 10,000 males 45-54y.o. (95% CI 0.67,4.59) and 9.7 hospitalizations per 10,000 females 75y.o.+ (95% CI 1.92,17.42), 25.8% and 24.2% increases respectively. As for mortality rates, a hundred cumulative wells is associated with an increase of 0.09 deaths per 10,000 males 45-54y.o. (95% CI 0.02,0.16), a 5.3% increase. Conclusions Cumulative UNGD is associated with increased AMI hospitalization rates among middle-aged men, older men and older women as well as with increased AMI mortality among middle-aged men. Our findings lend support for increased awareness about cardiovascular risks of UNGD and scaled-up AMI prevention as well as suggest that bans on hydraulic fracturing can be protective for public health.

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The oil and gas industry is variably classified in upstream sector and downstream sector, with both sectors having exposure to a good number of hazards. The crude oil extraction process is one of the prime objectives of the upstream sector which includes the exploration of the crude, subsequent drilling operation and maximum recovery of the crude oil and gas from the site of operation. The uncontrolled flow of hydrocarbon in well may lead to blowout and will probably have environmental impact; thus, the extraction process can have a huge impact on the elements of earth, which include the soil (area of exploration and production), water and air. Approximately on global scale, there are forty-thousand crude oil sites and millions of people work or live in nearby vicinity; and workers associated with the job will be largely influenced in regard of their safety and health. On comparison of O & G extraction industry with the construction industry, the fatality rate goes up by 2.5 times (Goldberg and Moye in the first hundred years of the Bureau of Labor Statistics. US Department of Labor, 1985), as exposure to hazards like noise, radiation, H2S, crystalline silica is significant. In the article further, we review the safety hazards and health hazards associated with the extraction of the crude along with assessing the probable causes of the fatal incidents and exposure to hazardous substances. Workers involved in crude extraction process have potential impact on their health such as loss of immunity, cancerous cell development, liver and respiratory tract damage and neurological disorders.

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Over the past decade, the shale gas boom has led to increasing public concerns regarding communities' exposure to air pollutants from shale gas development resulting in concentrations higher than the EPA's National Ambient Air Quality Standards. This study investigates the sufficiency of current policy in Pennsylvania to protect people from exposure to fine particulate matter (PM2.5) emissions from such development. We used a Gaussian plume model to simulate PM2.5 concentrations over the Marcellus shale region of Pennsylvania, and using census block data, we estimated the potential number of people who experienced exceedance of the PM2.5 standard between 2005 and 2017. Results demonstrate that these emissions could increase the number of exceedances by more than 36,000 persons in a single year which is almost 1% of the Marcellus shale regional population in Pennsylvania. This number has largely been proportional to the overall number of developed wells, but development histories show that similar levels of development could occur with reduced population exposure. Setback policy is shown to be an effective method to reduce exposure exceedances, but results suggest that it should be revised based on the number of wells per wellpad as well as the local conditions to further limit air quality impacts.

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Background: Oil and natural gas extraction may produce environmental pollution at levels that affect reproductive health of nearby populations. Available studies have primarily focused on unconventional gas drilling and have not accounted for local population changes that can coincide with drilling activity. Objective: Our study sought to examine associations between residential proximity to oil and gas drilling and adverse term birth outcomes using a difference-in-differences study design. Methods: We created a retrospective population-based term birth cohort in Texas between 1996 and 2009 composed of mother–infant dyads ( n=2,598,025 n=2,598,025 ) living <10km <10km from an oil or gas site. We implemented a difference-in-differences approach to estimate associations between drilling activities and infant health: term birth weight and term small for gestational age (SGA). Using linear and logistic regression, we modeled interactions between births before (unexposed) or during (exposed) drilling activity and residential proximity near (0–1, 1–2, or 2–3km 2–3km ) or far ( 3–10km 3–10km ) from an active or future drilling site, adjusting for individual- and neighborhood-level characteristics. Results: The adjusted mean difference in term birth weight for mothers living 0–1 vs. 3–10km 3–10km from a current or future drilling site was –7.3g –7.3g [95% confidence interval (CI): –11.6 –11.6 , –3.0 –3.0 ] for births during active vs. future drilling. The corresponding adjusted odds ratio for SGA was 1.02 (95% CI: 0.98, 1.06). Negative associations with term birth weight were observed for the 1–2 and 2–3km 2–3km near groups, and no consistent differences were identified by type of drilling activity. Larger, though imprecise, adverse associations were found for infants born to Hispanic women, women with the lowest educational attainment, and women living in cities. Conclusions: Residing near oil and gas drilling sites during pregnancy was associated with a small reduction in term birth weight but not SGA, with some evidence of environmental injustices. Additional work is needed to investigate specific drilling-related exposures that might explain these associations. https://doi.org/10.1289/EHP7678

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The shale gas boom revolutionized the energy sector through hydraulic fracturing (fracking). High levels of energy production force communities, states, and nations to consider the externalities and potential risks associated with this unconventional oil and natural gas development (UOGD). In this review, we systematically outline the environmental, economic, and anthropogenic impacts of UOGD, while also considering the diverse methodological approaches to these topics. We summarize the current status and conclusions of the academic literature, in both economic and related fields, while also providing suggested avenues for future research. Causal inference will continue to be important for the evaluation of UOGD costs and benefits. We conclude that current economic, global, and health forces may require researchers to revisit outcomes in the face of a potential shale bust. Expected final online publication date for the Annual Review of Resource Economics, Volume 13 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Hydraulic fracturing (“fracking”) is a process in which subterranean natural gas-laden rock is fractured under pressure to enhance retrieval of gas. Sand (a “proppant”) is present in the fracking fluid pumped down the well bore to stabilize the fissures and facilitate gas flow. The manipulation of sand at the well site creates respirable dust (fracking sand dust, FSD) to which workers are exposed. Because workplace exposures to FSD have exceeded exposure limits set by OSHA, a physico-chemical characterization of FSD along with comprehensive investigations of the potential early adverse effects of FSDs on organ function and biomarkers has been conducted using a rat model and related in vivo and in vitro experiments involving the respiratory, cardiovascular, immune systems, kidney and brain. An undercurrent theme of the overall hazard identification study was, to what degree do the health effects of inhaled FSD resemble those previously observed after crystalline silica dust inhalation? In short-term studies, FSD was found to be less bioactive than MIN-U-SIL® 5 in the lungs. A second theme was, are the biological effects of FSD restricted to the lungs? Bioactivity of FSD was observed in all examined organ systems. Our findings indicate that, in many respects, the physical and chemical properties, and the short-term biological effects, of the FSDs share many similarities as a group but have little in common with crystalline silica dust.

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Unconventional oil and gas development (UOGD) expanded rapidly in the United States between 2004 and 2019 with resultant industrial change to landscapes and new environmental exposures. By 2019, West Texas’ Permian Basin accounted for 35% of domestic oil production. We conducted an online survey of 566 Texans in 2019 to examine the implications of UOGD using three measures from the Environmental Distress Scale (EDS): perceived threat of environmental issues, felt impact of environmental change, and loss of solace when valued environments are transformed (“solastalgia”). We found increased levels of environmental distress among respondents living in counties in the Permian Basin who reported a 2.75% increase in perceived threat of environmental issues (95% CI = −1.14, 6.65) and a 4.21% increase in solastalgia (95% CI = 0.03, 8.40). In our subgroup analysis of women, we found higher EDS subscale scores among respondents in Permian Basin counties for perceived threat of environmental issues (4.08%, 95% CI = −0.12, 8.37) and solastalgia (7.09%, 95% CI = 2.44, 11.88). In analysis restricted to Permian Basin counties, we found exposure to at least one earthquake of magnitude ≥ 3 was associated with increases in perceived threat of environmental issues (4.69%, 95% CI = 0.15, 9.23), and that county-level exposure to oil and gas injection wells was associated with increases in felt impact (4.38%, 95% CI = −1.77, 10.54) and solastalgia (4.06%, 95% CI = 3.02, 11.14). Our results indicate increased environmental distress in response to UOGD-related environmental degradation among Texans and highlight the importance of considering susceptible sub-groups.

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Unconventional oil and gas (UOG) production has rapidly expanded, making the U.S. the top producer of hydrocarbons. The industrial process now pushes against neighborhoods, schools, and people’s daily lives. I analyze extensive mixed methods data collected over three years in Colorado – including 75 in-depth interviews and additional participant observation – to show how living amid industrial UOG production generates chronic stress and negative mental health outcomes, such as self-reported depression. I show how UOG production has become a neighborhood industrial activity that, in turn, acts as a chronic environmental stressor. I examine two key drivers of chronic stress – uncertainty and powerlessness – and show how these mechanisms relate to state-level institutional processes that generate patterned procedural inequities. This includes inadequate access to transparent environmental and public health information about UOG production’s potential risks and limited public participation in decisions about production, with negative implications for mental health.

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Unconventional natural gas developments (UNGD) may release air and water pollutants into the environment, potentially increasing the risk of birth defects. We conducted a case-control study evaluating 52,955 cases with birth defects and 642,399 controls born between 1999 and 2011 to investigate the relationship between UNGD exposure and the risk of gastroschisis, congenital heart defects (CHD), neural tube defects (NTDs), and orofacial clefts in Texas. We calculated UNGD densities (number of UNGDs per area) within 1, 3, and 7.5 km of maternal address at birth and categorized exposure by density tertiles. For CHD subtypes with large case numbers, we also performed time-stratified analyses to examine temporal trends. We calculated adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the association with UNGD exposure, accounting for maternal characteristics and neighborhood factors. We also included a bivariable smooth of geocoded maternal location in an additive model to account for unmeasured spatially varying risk factors. Positive associations were observed between the highest tertile of UNGD density within 1 km of maternal address and risk of anencephaly (aOR: 2.44, 95% CI: 1.55, 3.86), spina bifida (aOR: 2.09, 95% CI: 1.47, 2.99), gastroschisis among older mothers (aOR: 3.19, 95% CI: 1.77, 5.73), aortic valve stenosis (aOR: 1.90, 95% CI: 1.33, 2.71), hypoplastic left heart syndrome (aOR: 2.00, 95% CI: 1.39, 2.86), and pulmonary valve atresia or stenosis (aOR: 1.36, 95% CI: 1.10, 1.66). For CHD subtypes, results did not differ substantially by distance from maternal address or when residual confounding was considered, except for atrial septal defects. We did not observe associations with orofacial clefts. Our results suggest that UNGDs were associated with some CHDs and possibly NTDs. In addition, we identified temporal trends and observed presence of spatial residual confounding for some CHDs.

Abstract:
Hydraulic fracturing is used to access oil and natural gas reserves. This process involves the high-pressure injection of fluid to fracture shale. Fracking fluid contains approximately 95% water, chemicals and 4.5% fracking sand. Workers may be exposed to fracking sand dust (FSD) during the manipulation of the sand, and negative health consequences could occur if FSD is inhaled. In the absence of any information about its potential toxicity, a comprehensive rat animal model study (see Fedan et al., 2020) was designed to investigate the bioactivities of several FSDs in comparison to MIN-U-SIL® 5, a respirable α-quartz reference dust used in previous animal models of silicosis, in several organ systems. The goal of this study was to assess the effects of inhalation of one FSD, i.e., FSD 8, on factors and tissues that affect cardiovascular function. Male rats were exposed to 10 or 30 mg/m3 FSD (6 h/d for 4 d) by whole body inhalation, with measurements made 1, 7 or 27 d post-exposure. One day following exposure to 10 mg/m3 FSD the sensitivity to phenylephrine-induced vasoconstriction in tail arteries in vitro was increased. FSD exposure at both doses resulted in decreases in heart rate (HR), HR variability, and blood pressure in vivo. FSD induced changes in hydrogen peroxide concentrations and transcript levels for pro-inflammatory factors in heart tissues. In kidney, expression of proteins indicative of injury and remodeling was reduced after FSD exposure. When analyzed using regression analysis, changes in proteins involved in repair and remodeling were correlated. Thus, it appears that inhalation of FSD does have some prolonged effects on cardiovascular, and, possibly, renal function. The findings also provide information regarding potential mechanisms that may lead to these changes, and biomarkers that could be examined to monitor physiological changes that could be indicative of impending cardiovascular dysfunction.

Abstract:
Hydraulic fracturing flowback and produced water (FPW) is a highly complex and heterogenous wastewater by-product of hydraulic fracturing practices. To date, no research has examined how FPW exposure to freshwater biota may affect energetic homeostasis following subsequent induction of detoxification processes. Rainbow trout (Oncorhynchus mykiss) were acutely exposed for 48 h to either 2.5% or 7.5% FPW, and hepatic metabolism was assessed either immediately or following a 3-week recovery period. Induction of xenobiotic metabolism was observed with an 8.8-fold increase in ethoxyresorufin-O-deethylase (EROD) activity after 48 h exposure to 7.5% FPW, alongside a 10.3-fold increase in the mRNA abundance of cyp1a, both of which returned to basal level after three weeks. Glucose uptake capacity was elevated by 6.8- and 12.9-fold following 2.5% and 7.5% FPW exposure, respectively, while alanine uptake was variable. Activity measurements and mRNA abundance of key enzymes involved in hepatic metabolism indicated that aerobic metabolism was maintained with exposure, as was glycolysis. Gluconeogenesis, as measured by phosphoenolpyruvate carboxykinase (PEPCK) activity, decreased by ~30% 48 h following 2.5% FPW exposure and ~20% 3 weeks after 7.5% FPW exposure. The abundance of pepck mRNA activity followed similar, yet non-significant, trends. Finally, a delayed increase in amino acid catabolism was observed, as glutamate dehydrogenase (GDH) activity was increased 2-fold in 7.5% FPW exposed fish when compared to saline control fish at the 3-week time point. We provide evidence to suggest that although hepatic metabolism is altered following acute FPW exposure, metabolic homeostasis generally returns 3-weeks post-exposure.

Abstract:
Publicly available toxicological studies on wastewaters associated with unconventional oil and gas (UOG) activities in offshore regions are nonexistent. The current study investigated the impact of hydraulic fracturing-generated flowback water (HF-FW) on whole organism swimming performance/respiration and cardiomyocyte contractility dynamics in mahi-mahi (Coryphaena hippurus—hereafter referred to as “mahi”), an organism which inhabits marine ecosystems where offshore hydraulic fracturing activity is intensifying. Following exposure to 2.75% HF-FW for 24 h, mahi displayed significantly reduced critical swimming speeds (Ucrit) and aerobic scopes (reductions of ∼40 and 61%, respectively) compared to control fish. Additionally, cardiomyocyte exposures to the same HF-FW sample at 2% dilutions reduced a multitude of mahi sarcomere contraction properties at various stimulation frequencies compared to all other treatment groups, including an approximate 40% decrease in sarcomere contraction size and a nearly 50% reduction in sarcomere relaxation velocity compared to controls. An approximate 8-fold change in expression of the cardiac contractile regulatory gene cmlc2 was also seen in ventricles from 2.75% HF-FW-exposed mahi. These results collectively identify cardiac function as a target for HF-FW toxicity and provide some of the first published data on UOG toxicity in a marine species.

Abstract:
Hydraulic fracturing (“fracking”) is a process used to enhance retrieval of gas from subterranean natural gas-laden rock by fracturing it under pressure. Sand used to stabilize fissures and facilitate gas flow creates a potential occupational hazard from respirable fracking sand dust (FSD). As studies of the immunotoxicity of FSD are lacking, the effects of whole-body inhalation (6 h/d for 4 d) of a FSD, i.e., FSD 8, was investigated at 1, 7, and 27 d post-exposure in rats. Exposure to 10 mg/m3 FSD 8 resulted in decreased lung-associated lymph node (LLN) cellularity, total B-cells, CD4+ T-cells, CD8+ T-cells and total natural killer (NK) cells at 7-d post exposure. The frequency of CD4+ T-cells decreased while the frequency of B-cells increased (7 and 27 d) in the LLN. In contrast, increases in LLN cellularity and increases in total CD4+ and CD8+ T-cells were observed in rats following 30 mg/m3 FSD 8 at 1 d post-exposure. Increases in the frequency and number of CD4+ T-cells and NK cells were observed in bronchial alveolar lavage fluid at 7-d post-exposure (10 mg/m3) along with an increase in total CD4+ T-cells, CD11b + cells, and NK cells at 1-day post-exposure (30 mg/m3). Increases in the numbers of B-cells and CD8+ T-cells were observed in the spleen at 1-day post 30 mg/m3 FSD 8 exposure. In addition, NK cell activity was suppressed at 1 d (30 mg/m3) and 27 d post-exposure (10 mg/m3). No change in the IgM response to sheep red blood cells was observed. The findings indicate that FSD 8 caused alterations in cellularity, phenotypic subsets, and impairment of immune function.

Abstract:
Recent research has shown relationships between health outcomes and residence proximity to unconventional oil and natural gas development (UOGD). The challenge of connecting health outcomes to environmental stressors requires ongoing research with new methodological approaches. We investigated UOGD density and well emissions and their association with symptom reporting by residents of southwest Pennsylvania. A retrospective analysis was conducted on 104 unique, de-identified health assessments completed from 2012–2017 by residents living in proximity to UOGD. A novel approach to comparing estimates of exposure was taken. Generalized linear modeling was used to ascertain the relationship between symptom counts and estimated UOGD exposure, while Threshold Indicator Taxa Analysis (TITAN) was used to identify associations between individual symptoms and estimated UOGD exposure. We used three estimates of exposure: cumulative well density (CWD), inverse distance weighting (IDW) of wells, and annual emission concentrations (AEC) from wells within 5 km of respondents’ homes. Taking well emissions reported to the Pennsylvania Department of Environmental Protection, an air dispersion and screening model was used to estimate an emissions concentration at residences. When controlling for age, sex, and smoker status, each exposure estimate predicted total number of reported symptoms (CWD, p<0.001; IDW, p<0.001; AEC, p<0.05). Akaike information criterion values revealed that CWD was the better predictor of adverse health symptoms in our sample. Two groups of symptoms (i.e., eyes, ears, nose, throat; neurological and muscular) constituted 50% of reported symptoms across exposures, suggesting these groupings of symptoms may be more likely reported by respondents when UOGD intensity increases. Our results do not confirm that UOGD was the direct cause of the reported symptoms but raise concern about the growing number of wells around residential areas. Our approach presents a novel method of quantifying exposures and relating them to reported health symptoms.

Abstract:
The unconventional oil and gas (UOG) boom in the United States produced a surge of social science research activity about the industry's local impacts, the vast majority of which relied on local stakeholders to contribute data. Like UOG development across the United States, research on the local impacts of UOG has been geographically dispersed and uneven and mostly uncoordinated. The primary purpose of this systematic review of peer-reviewed articles and theses and dissertations is to provide an overview of the timing, spatial distribution, and methods used in research on local impacts of UOG development since 2000. The study identifies 167 unique human subject data collection efforts in U.S. UOG locations between 2000 and 2018. This overview—along with analysis of response rates and recruitment and engagement patterns—reveals risks that the recent boom in impacts research may have contributed to research fatigue on the part of some human subject research participants. The study also demonstrates challenges in deriving generalizable observations from local impacts research. Both problems are associated with the uneven geographic distribution of research across UOG locations in the U.S., researchers’ tendency to arrive at the height of development activity, inconsistent and incomplete reporting on methods in publications, and an over-reliance on accessible research subjects. Future research and scholarly reflection should evaluate constraints and factors that influence research strategies. In the meantime, the U.S. research community faces an imperative to consider opportunities to enhance and coordinate research activities in energy communities.

Abstract:
Hydraulic fracturing, a method used in Northeastern British Columbia (Canada) to extract natural gas, can release contaminants with potential deleterious health effects on fetal development. To date, the association between hydraulic fracturing activity and birth outcomes has not been evaluated in this region.

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This paper examines the impact of the U.S. fracking boom on local STI transmission rates and prostitution activity as measured by online prostitution review counts. We first document significant and robust positive effects on gonorrhea rates in fracking counties at the national level. But we find no evidence that fracking increases prostitution when using our national data, suggesting sex work may not be the principal mechanism linking fracking to gonorrhea growth. To explore mechanisms, we then focus on remote, high-fracking production areas that experienced large increases in sex ratios due to male in-migration. For this restricted sample we find enhanced gonorrhea transmission effects and moderate evidence of extensive margin effects on prostitution markets. This study highlights public health concerns relating to economic shocks and occupational conditions that alter the local demographic composition.

Abstract:
Hydraulic fracturing (HF) technology is increasingly utilized for oil and gas extraction operations. The widespread use of HF has led to concerns of negative impacts on both the environment and human health. Indeed, the potential endocrine disrupting impacts of HF chemicals is one such knowledge gap. Herein, we used structure-based molecular docking to assess the binding affinities of 60 HF chemicals to the human androgen receptor (AR). Five HF chemicals had relatively high predicted AR binding affinity, suggesting the potential for endocrine disruption. We next assessed androgenic and antiandrogenic activities of these chemicals in vitro. Of the five candidate AR ligands, only Genapol®X–100 significantly modified AR transactivation. To better understand the structural effect of Genapol®X–100 on the potency of AR inhibition, we compared the antiandrogenic activity of Genapol®X–100 with that of its structurally similar chemical, Genapol®X–080. Interestingly, both Genapol®X–100 and Genapol®X–080 elicited an antagonistic effect at AR with 20% relative inhibitory concentrations of 0.43 and 0.89 μM, respectively. Furthermore, we investigated the mechanism of AR inhibition of these two chemicals in vitro, and found that both Genapol®X–100 and Genapol®X–080 inhibited AR through a noncompetitive mechanism. The effect of these two chemicals on the expression of AR responsive genes, e.g. PSA, KLK2, and AR, was also investigated. Genapol®X–100 and Genapol®X–080 altered the expression of these genes. Our findings heighten awareness of endocrine disruption by HF chemicals and provide evidence that noncompetitive antiandrogenic Genapol®X–100 could cause adverse endocrine health effects.

Abstract:
Increasing reliance on natural gas for energy has resulted in expansion of the natural gas infrastructure, including pipelines and compressor stations to transport gas. Compressor stations emit numerous particulate and gaseous pollutants including volatile organic compounds (VOCs) but studies of human health in association with compressor stations are almost completely absent from the literature. The objective of the study was to test for associations between VOC emissions from compressor stations and adjusted mortality rates. We conducted a county-level ecological study, using VOC emission data from the 2017 National Emissions Inventory, 2017 age-adjusted total mortality per 100,000 population from CDC data, and covariates from the County Health Rankings data. Results of multiple linear regression models showed that total age-adjusted mortality, controlling for covariates (race/ethnicity, education, poverty, urbanicity, smoking and obesity rates), was significantly higher in association with greater non-methane VOC emissions from compressor stations. Twelve individual VOCs were also associated with significantly higher adjusted mortality. Results provide preliminary evidence that compressor stations along natural gas pipelines are sources of pollutant exposures that may contribute to adverse human health outcomes.

Abstract:
The use of hydraulic fracturing (HF) to extract oil and natural gas has increased, along with intensive discussions on the associated risks to human health. Three technical processes should be differentiated when evaluating human health risks, namely (1) drilling of the borehole, (2) hydraulic stimulation, and (3) gas or oil production. During the drilling phase, emissions such as N­ Ox, NMVOCs (non-methane volatile organic compounds) as precursors for tropospheric ozone formation, and ­SOx have been shown to be higher compared to the subsequent phases. In relation to hydraulic stimulation, the toxicity of frac fluids is of relevance. More than 1100 compounds have been identified as components. A trend is to use fewer, less hazardous and more biodegradable substances; however, the use of hydrocarbons, such as kerosene and diesel, is still allowed in the USA. Methane in drinking water is of low toxicological relevance but may indicate inadequate integrity of the gas well. There is a great concern regarding the contamination of ground- and surface water during the production phase. Water that flows to the surface from oil and gas wells, so-called ‘produced water’, represents a mixture of flow-back, the injected frac fluid returning to the surface, and the reservoir water present in natural oil and gas deposits. Among numerous hazardous compounds, produced water may contain bromide, arsenic, strontium, mercury, barium, radioactive isotopes and organic compounds, particularly benzene, toluene, ethylbenzene and xylenes (BTEX). The sewage outflow, even from specialized treatment plants, may still contain critical concentrations of barium, strontium and arsenic. Evidence suggests that the quality of groundwater and surface water may be compromised by disposal of produced water. Particularly critical is the use of produced water for watering of agricultural areas, where persistent compounds may accumulate. Air contamination can occur as a result of several HF-associated activities. In addition to BTEX, 20 HF-associated air contaminants are group 1A or 1B carcinogens according to the IARC. In the U.S., oil and gas production (including conventional production) represents the second largest source of anthropogenic methane emissions. High-quality epidemiological studies are required, especially in light of recent observations of an association between childhood leukemia and multiple myeloma in the neighborhood of oil and gas production sites. In conclusion, (1) strong evidence supports the conclusion that frac fluids can lead to local environmental contamination; (2) while changes in the chemical composition of soil, water and air are likely to occur, the increased levels are still often below threshold values for safety; (3) point source pollution due to poor maintenance of wells and pipelines can be monitored and remedied; (4) risk assessment should be based on both hazard and exposure evaluation; (5) while the concentrations of frac fluid chemicals are low, some are known carcinogens; therefore, thorough, well-designed studies are needed to assess the risk to human health with high certainty; (6) HF can represent a health risk via long-lasting contamination of soil and water, when strict safety measures are not rigorously applied.

Abstract:
Studies of neonatal health risks of unconventional natural gas development (UNGD) have not included comprehensive assessments of environmental chemical exposures. We investigated a clustering of dysphagic cases in neonatal foals born between 2014 and 2016 in an area of active UNGD in Pennsylvania (PA),USA. We evaluated equine biological data and environmental exposures on the affected PA farm and an unaffected New York (NY) farm owned by the same proprietor. Dams either spent their entire gestation on one farm or moved to the other farm in late gestation. Over the 21-month study period, physical examinations and blood/tissue samples were obtained from mares and foals on each farm. Grab samples of water, pasture soil and feed were collected; continuous passive sampling of air and water for polycyclic aromatic hydrocarbons was performed. Dysphagia was evaluated as a binary variable; logistic regression was used to identify risk factors. Sixty-five foals were born, 17 (all from PA farm) were dysphagic. Odds of dysphagia increased with the dam residing on the PA farm for each additional month of gestation (OR = 1.4, 95% CI 1.2, 1.7, p = 6.0E-04). Males were more likely to be born dysphagic (OR = 5.5, 95% CI 1.2, 24.5, p = 0.03) than females. Prior to installation of a water filtration/treatment system, PA water concentrations of 3,6-dimethylphenanthrene (p = 6.0E-03), fluoranthene (p = 0.03), pyrene (p = 0.02) and triphenylene (p = 0.01) exceeded those in NY water. Compared to NY farm water, no concentrations of PAHs were higher in PA following installation of the water filtration/treatment system. We provide evidence of an uncommon adverse health outcome (dysphagia) in foals born near UNGD that was eliminated in subsequent years (2017–2019) following environmental management changes. Notably, this study demonstrates that domestic large animals such as horses can serve as important sentinels for human health risks associated with UNGD activities.

Abstract:
Unconventional extraction techniques including hydraulic fracturing or “fracking” have led to a boom in oil and gas production the Eagle Ford shale play, Texas, one of the most productive regions in the United States. Nearly 400,000 people live within 5 km of an unconventional oil or gas well in this largely rural area. Flaring is associated primarily with unconventional oil wells and is an increasingly common practice in the Eagle Ford to dispose of excess gas through combustion. Flares can operate continuously for months and release hazardous air pollutants such as particulate matter and volatile organic compounds in addition to causing light and noise pollution and noxious odors. We estimated ethnic disparities in exposure to flaring using satellite observations from the Visible Infrared Imaging Spectroradiometer between March 2012-December 2016. Census blocks with majority Hispanic (>60%) populations were exposed to twice as many nightly flare events within 5 km as those with <20% Hispanics. We found that Hispanics were exposed to more flares despite being less likely than non-Hispanic White residents to live near unconventional oil and gas wells. Our findings suggest Hispanics are disproportionately exposed to flares in the Eagle Ford Shale, a pattern known as environmental injustice, which could contribute to disparities in air pollution and other nuisance exposures.

Abstract:
Unconventional oil and natural gas extraction (UOG) combines directional drilling and hydraulic fracturing and produces billions of liters of wastewater per year. Herein, we review experimental studies that evaluated the potential endocrine-mediated health impacts of exposure to a mixture of 23 UOG chemicals commonly found in wastewater. The purpose of this manuscript is to synthesize and summarize a body of work using the same UOG-mix but with different model systems and physiological endpoints in multiple experiments. The studies reviewed were conducted in laboratory animals (mice or tadpoles) and human tissue culture cells. A key feature of the in vivo studies was the use of four environmentally relevant doses spanning three orders of magnitude ranging from concentrations found in surface and ground water in UOG dense areas to concentrations found in UOG wastewater. This UOG-mix exhibited potent antagonist activity for the estrogen, androgen, glucocorticoid, progesterone, and thyroid receptors in human tissue culture cells. Subsequently, pregnant mice were administered the UOG-mix in drinking water and offspring were examined in adulthood or to tadpoles. Developmental exposure profoundly impacted pituitary hormone concentrations, reduced sperm counts, altered folliculogenesis, and increased mammary gland ductal density and preneoplastic lesions in mice. It also altered energy expenditure, exploratory and risk-taking behavior, the immune system in three immune models in mice, and affected basal and antiviral immunity in frogs. These findings highlight the diverse systems affected by developmental EDC exposure and the need to examine human and animal health in UOG regions.

Abstract:
Background Hydraulic fracturing together with directional and horizontal well drilling (unconventional oil and gas (UOG) development) has increased substantially over the last decade. UOG development is a complex process presenting many potential environmental health hazards, raising serious public concern. Aim To conduct a scoping review to assess what is known about the human health outcomes associated with exposure to UOG development. Methods We performed a literature search in MEDLINE and SCOPUS for epidemiological studies of exposure to UOG development and verified human health outcomes published through August 15, 2019. For each eligible study we extracted data on the study design, study population, health outcomes, exposure assessment approach, statistical methodology, and potential confounders. We reviewed the articles based on categories of health outcomes. Results We identified 806 published articles, most of which were published during the last three years. After screening, 40 peer-reviewed articles were selected for full text evaluation and of these, 29 articles met our inclusion criteria. Studies evaluated pregnancy outcomes, cancer incidence, hospitalizations, asthma exacerbations, sexually transmitted diseases, and injuries or mortality from traffic accidents. Our review found that 25 of the 29 studies reported at least one statistically significant association between the UOG exposure metric and an adverse health outcome. The most commonly studied endpoint was adverse birth outcomes, particularly preterm deliveries and low birth weight. Few studies evaluated the mediating pathways that may underpin these associations, highlighting a clear need for research on the potential exposure pathways and mechanisms underlying observed relationships. Conclusions This review highlights the heterogeneity among studies with respect to study design, outcome of interest, and exposure assessment methodology. Though replication in other populations is important, current research points to a growing body of evidence of health problems in communities living near UOG sites.

Abstract:
Hydraulic fracturing, a.k.a., fracking, requires intense truck trips to transport a large volume of water within a narrow time window, posing a safety threat to other road users. This paper examines how fracking-related trucking affects fatal crashes in North Dakota using the exogenous timing of fracking operations near a road segment. The results show that an additional post-fracking well within six miles of a road segment led to 8% more fatal crashes and 7.1% higher per-capita costs in accidents. Transport activities at wells’ other operational stages did not affect fatal crashes. These additional crashes emerged mainly from collisions involving trucks, resulting from a higher traffic volume rather than a higher crash rate and occurring during daytime rush hours rather than during the rest of the day. Alcohol-involved crash drivers increased most likely due to their vulnerability to heavier fracking-induced traffic rather than more alcohol-involved truck drivers near the fracking sites.

Abstract:
Purpose of ReviewPolluting industries are more likely to be located in low-income communities of color who also experience greater social stressors that may make them more vulnerable than others to the health impacts of toxic chemical exposures. We describe recent developments in assessing pollutant exposures and health threats posed by industrial facilities using or releasing synthetic chemicals to nearby communities in the U.S.Recent FindingsMore people are living near oil and gas development due to the expansion of unconventional extraction techniques as well as near industrial animal operations, both with suggestive evidence of increased exposure to hazardous pollutants and adverse health effects. Legacy contamination continues to adversely impact a new generation of residents in fenceline communities, with recent studies documenting exposures to toxic metals and poly- and perfluoroalkyl substances (PFASs). Researchers are also giving consideration to acute exposures resulting from inadvertent industrial chemical releases, including those resulting from extreme weather events linked to climate change. Natural experiments of industrial closures or cleanups provide compelling evidence that exposures from industry harm the health of nearby residents.SummaryNew and legacy industries, coupled with climate change, present unique health risks to communities living near industry due to the release of toxic chemicals. Cumulative impacts from multiple stressors faced by environmental justice communities may amplify these adverse effects.

Abstract:
Rural places in the United States increasingly face seemingly intractable problems—perhaps the most severe of these is the ‘rural mortality penalty’ wherein rural places have higher mortality rates than suburban and urban places. The boom in unconventional oil and gas production in the mid-2000s brought with it the promise of rural renewal, and the potential to address rural America’s long-standing development challenges. In this analysis, we ask how the oil and gas boom has impacted the rural mortality penalty. Our results imply that oil and gas development will not improve or damage mortality rates. Implications for rural populations are discussed. Keywords: Rural mortality penalty; oil and gas development; multilevel model

Abstract:
In their study "Assessing Agreement in Exposure Classification between Proximity-Based Metrics and Air Monitoring Data in Epidemiology Studies of Unconventional Resource Development" [...].

Abstract:
Background Fossil fuel extraction from deep shale rock formations using new drilling technologies such as hydraulic fracturing, has rapidly increased in the Unites States (U.S.) over the past decade. Increases in nonlocal, specialized workers to meet the demands of this complex industry have been suggested to influence rates of sexually transmitted infections (STI) in counties with shale drilling activity; these associations may vary geographically. In this multi-region analysis, we examine the associations between shale drilling activity and rates of three reportable STI in Colorado, North Dakota, and Texas, states with active shale drilling. Methods We obtained annual reported rates of chlamydia, gonorrhea, and syphilis from the Centers for Disease Control and Prevention (CDC), number of active shale wells from Enverus (formerly known as DrillingInfo), and sociodemographic covariates from the U.S. Census Bureau. We used multivariable mixed-effects Poisson regression modeling to estimate rate ratios (RR) with 95% confidence intervals (CIs) adjusted for potential confounders and secular trends. Results In Texas, county-years with high drilling activity had 10% increased rates of chlamydia (RR=1.10; 95% CI=1.04-1.17) and 15% increased rates of gonorrhea (RR=1.15; 95% CI = 1.04-1.28), compared to county-years with no drilling. No statistically significant associations were reported for syphilis or for any STIs in Colorado or North Dakota. Conclusions Associations between shale drilling and chlamydia and gonorrhea in Texas may reflect increased risk in areas with higher drilling activity and a greater number of major metropolitan areas. Inter-state differences highlight the need for local epidemiology to prioritize community health policies.