Childhood cancer incidence in Pennsylvania counties in relation to living in counties with hydraulic fracturing sites

The human health effects of unconventional oil and gas development (UOGD): A scoping review of epidemiologic studies

OBJECTIVE

Unconventional oil and gas development (UOGD, sometimes termed "fracking" or "hydraulic fracturing") is an industrial process to extract methane gas and/or oil deposits. Many chemicals used in UOGD have known adverse human health effects. Canada is a major producer of UOGD-derived gas with wells frequently located in and around rural and Indigenous communities. Our objective was to conduct a scoping review to identify the extent of research evidence assessing UOGD exposure-related health impacts, with an additional focus on Canadian studies.

METHODS

We included English- or French-language peer-reviewed epidemiologic studies (January 2000-December 2022) which measured exposure to UOGD chemicals directly or by proxy, and where health outcomes were plausibly caused by UOGD-related chemical exposure. Results synthesis was descriptive with results ordered by outcome and hierarchy of methodological approach.

SYNTHESIS

We identified 52 studies from nine jurisdictions. Only two were set in Canada. A majority (n = 27) used retrospective cohort and case-control designs. Almost half (n = 24) focused on birth outcomes, with a majority (n = 22) reporting one or more significant adverse associations of UOGD exposure with: low birthweight; small for gestational age; preterm birth; and one or more birth defects. Other studies identified adverse impacts including asthma (n = 7), respiratory (n = 13), cardiovascular (n = 6), childhood acute lymphocytic leukemia (n = 2), and all-cause mortality (n = 4).

CONCLUSION

There is a growing body of research, across different jurisdictions, reporting associations of UOGD with adverse health outcomes. Despite the rapid growth of UOGD, which is often located in remote, rural, and Indigenous communities, Canadian research on its effects on human health is remarkably sparse. There is a pressing need for additional evidence.

Clustering of Pediatric Brain Tumors in Texas, 2000-2017

Risk factors for pediatric brain tumors are largely unknown. Identifying spatial clusters of these rare tumors on the basis of residential address may provide insights into childhood socio-environmental factors that increase susceptibility. From 2000-2017, the Texas Cancer Registry recorded 4305 primary brain tumors diagnosed among children (≤19 years old). We performed a spatial analysis in SaTScan to identify neighborhoods (census tracts) where the observed number of pediatric brain tumors was higher than expected. Within each census tract, the number of pediatric brain tumors was summed on the basis of residential address at diagnosis. The population estimate from the 2007-2011 American Community Survey of 0- to 19-year-olds was used as the at-risk population. p-values were calculated using Monte Carlo hypothesis testing. The age-standardized rate was 54.3 per 1,000,000. SaTScan identified twenty clusters, of which two were statistically significant (p < 0.05). Some of the clusters identified in Texas spatially implicated potential sources of environmental risk factors (e.g., proximity to petroleum production processes) to explore in future research. This work provides hypothesis-generating data for further investigations of spatially relevant risk factors of pediatric brain tumors in Texas.

Assessing Exposure to Unconventional Oil and Gas Development: Strengths, Challenges, and Implications for Epidemiologic Research

PURPOSE OF REVIEW

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.

RECENT FINDINGS

Exposure assessment challenges include (1) numerous potential stressors with distinct spatiotemporal patterns, (2) critical exposure windows that cover long periods and occur in the past, and (3) limited existing monitoring data coupled with the resource-intensiveness of collecting new exposure measurements to capture spatiotemporal variation. All epidemiologic studies used proximity-based models for exposure assessment as opposed to surveys, biomonitoring, or environmental measurements. Nearly all studies used aggregate (rather than pathway-specific) models, which are useful surrogates for the complex mix of potential hazards. Simple and less-specific exposure assessment approaches have benefits in terms of scalability, interpretability, and relevance to specific policy initiatives such as set-back distances. More detailed and specific models and metrics, including dispersion methods and stressor-specific models, could reduce exposure misclassification, illuminate underlying exposure pathways, and inform emission control and exposure mitigation strategies. While less practical in a large population, collection of multi-media environmental and biological exposure measurements would be feasible in cohort subsets. Such assessments are well-suited to provide insights into the presence and magnitude of exposures to UOG-related stressors in relation to spatial surrogates and to better elucidate the plausibility of observed effects in both children and adults.

Unconventional Oil and Gas Development Exposure and Risk of Childhood Acute Lymphoblastic Leukemia: A Case-Control Study in Pennsylvania, 2009-2017

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 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 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 (95% CI: 0.93, 3.27) and 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.

Managing upstream oil and gas emissions: A public health oriented approach

Oil and natural gas are the largest primary global energy sources, and upstream gas emissions from these fuels can impact global climate change and local public health. This paper employs a public health-oriented perspective that reviews grey and academic literature, industry data, technical reports, and policy trends to highlight issues of emissions monitoring. We identify gaps in the existing landscape of emissions reduction strategies and highlight options for addressing them. Policy recommendations include the use of new digital monitoring technologies to better understand causes of emission events, to create data-driven oil and gas regulations, and to begin accurately measuring the volumes of gases released during oil and gas production. Areas for future research relating to emissions and public health impacts are outlined to further enable oil and gas policy discussions.

Biological effects of inhaled hydraulic fracturing sand dust. I. Scope of the investigation

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.

Critical evaluation of human health risks due to hydraulic fracturing in natural gas and petroleum production

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 NOx, 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.

Unconventional oil and gas development and health outcomes: A scoping review of the epidemiological research

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.

A systematic assessment of carcinogenicity of chemicals in hydraulic-fracturing fluids and flowback water

BACKGROUND

Thousands of chemicals exist in hydraulic-fracturing (HF) fluids and wastewater from unconventional oil gas development. The carcinogenicity of these chemicals in HF fluids and wastewater has never been systematically evaluated.

OBJECTIVES

In this study, we assessed the carcinogenicity of 1,173 HF-related chemicals in the HF chemical data from the US Environmental Protection Agency (EPA).

METHODS

We linked the HF chemical data with the agent classification data from the International Agency for Research on Cancer (IARC) at the World Health Organization (WHO) (N = 998 chemicals) to evaluate human carcinogenic risk of the chemicals and with the Carcinogenic Potency Database (CPDB) from Toxnet (N = 1,534 chemicals) to evaluate potential carcinogenicity of the chemicals.

RESULTS

The Chemical Abstract Service Registry Numbers (CASRNs) for chemicals were used for data linkage. Among 1,173 chemicals, 1,039 were identified only in HF fluids, 97 only in wastewater, and 37 in both. Compared with IARC, we found information of 104 chemicals, and 48 of them may have potentially carcinogenic risk to human, among which 14 are definitely carcinogenic, 7 probably carcinogenic, and 27 possibly carcinogenic. Using the CPDB data, it suggests that 66 chemicals are potentially carcinogenic based on rats and mouse models.

CONCLUSIONS

Conclusions Our evaluation suggests that exposure to some chemicals in HF fluids and wastewater may increase cancer risk, and the identified chemicals could be selected as the priority list for drinking water exposure assessment or cancer-related health studies.

A Systematic Review of the Epidemiologic Literature Assessing Health Outcomes in Populations Living near Oil and Natural Gas Operations: Study Quality and Future Recommendations

A systematic method was used to review the existing epidemiologic literature and determine the state of the scientific evidence for potential adverse health outcomes in populations living near oil and natural gas (ONG) operations in the United States. The review utilized adapted systematic review frameworks from the medical and environmental health fields, such as Grading of Recommendations, Assessment, Development and Evaluations (GRADE), the Navigation Guide, and guidance from the National Toxicology Program’s Office of Health Assessment and Translation (OHAT). The review included 20 epidemiologic studies, with 32 different health outcomes. Studies of populations living near ONG operations provide limited evidence (modest scientific findings that support the outcome, but with significant limitations) of harmful health effects including asthma exacerbations and various self-reported symptoms. Study quality has improved over time and the highest rated studies within this assessment have primarily focused on birth outcomes. Additional high-quality studies are needed to confirm or dispute these correlations.

Examination of Child and Adolescent Hospital Admission Rates in Queensland, Australia, 1995-2011: A Comparison of Coal Seam Gas, Coal Mining, and Rural Areas

Objectives At present, coal seam gas (CSG) is the most common form of unconventional natural gas development occurring in Australia. Few studies have been conducted to explore the potential health impacts of CSG development on children and adolescents. This analysis presents age-specific hospitalisation rates for a child and adolescent cohort in three study areas in Queensland. Methods Three geographic areas were selected: a CSG area, a coal mining area, and a rural area with no mining activity. Changes in area-specific hospital admissions were investigated over the period 1995-2011 in a series of negative binomial regression analyses for 19 International Classification of Diseases (ICD) chapters, adjusting for sociodemographic factors. Results The strongest associations were found for respiratory diseases in 0-4 year olds (7% increase [95% CI 4%, 11%] and 6% increase [95% CI 2%, 10%] in the CSG area relative to the coal mining and rural areas, respectively) and 10-14 year olds (9% increase [95% CI 1%, 18%] and 11% increase [95% CI 1%, 21%] in the CSG area compared to the coal mining and rural areas, respectively). The largest effect size was for blood/immune diseases in 5-9 year olds in the CSG area (467% increase [95% CI 139%, 1244%]) compared to the rural area with no mining activity. Conclusions for Practice Higher rates of hospitalisation existed in the CSG area for certain ICD chapters and paediatric age groups, suggesting potential age-specific health impacts. This study provides insights on associations that should be explored further in terms of child and adolescent health.

Exposures and Health Risks from Volatile Organic Compounds in Communities Located near Oil and Gas Exploration and Production Activities in Colorado (U.S.A.)

The study objective was to use a preliminary risk based framework to evaluate the sufficiency of existing air data to answer an important public health question in Colorado: Do volatile organic compounds (VOCs) emitted into the air from oil and gas (OG) operations result in exposures to Coloradoans living at or greater than current state setback distances (500 feet) from OG operations at levels that may be harmful to their health? We identified 56 VOCs emitted from OG operations in Colorado and compiled 47 existing air monitoring datasets that measured these VOCs in 34 locations across OG regions. From these data, we estimated acute and chronic exposures and compared these exposures to health guideline levels using maximum and mean air concentrations. Acute and chronic non-cancer hazard quotients were below one for all individual VOCs. Hazard indices combining exposures for all VOCs were slightly above one. Lifetime excess cancer risk estimates for benzene were between 1.0 × 10⁻⁵–3.6 × 10⁻⁵ and ethylbenzene was 7.3 × 10⁻⁶. This evaluation identified a small sub-set of VOCs, including benzene and n-nonane, which should be prioritized for additional exposure characterization in site-specific studies that collect comprehensive time-series measurements of community scale exposures to better assess community exposures.

Exposure Assessment Using Secondary Data Sources in Unconventional Natural Gas Development and Health Studies

Studies of unconventional natural gas development (UNGD) and health have ranked participants along a gradient of geographic information system (GIS)-based activity that incorporated the distance between participants' home addresses and unconventional natural gas wells. However, studies have used different activity metrics, making result comparisons across the studies difficult. The existing studies have only incorporated wells, without accounting for other components of development (e.g., compressors, impoundments, and flaring events), for which it is often difficult to obtain reliable data but may have relevance to health. Our aims were to (1) describe, in space and time, UNGD-related compressors, impoundments, and flaring events; (2) evaluate whether and how to incorporate these into UNGD activity assessment; and (3) evaluate associations of these different approaches with mild asthma exacerbations. We identified 361 compressor stations, 1218 impoundments, and 216 locations with flaring events. A principal component analysis identified a single component that was approximately an equal mix of the metrics for compressors, impoundments, and four phases of well development (pad preparation, drilling, stimulation, and production). However, temporal coverage for impoundments and flaring data was sparse. Ultimately, we evaluated three UNGD activity metrics, including two based on the existing studies and a novel metric that included well pad development, drilling, stimulation, production, and compressor engine aspects of UNGD. The three metrics had varying magnitudes of association with mild asthma exacerbations, although the highest category of each metric (vs the lowest) was associated with the outcome.

A review of the public health impacts of unconventional natural gas development

The public health impact of hydraulic fracturing remains a high profile and controversial issue. While there has been a recent surge of published papers, it remains an under-researched area despite being possibly the most substantive change in energy production since the advent of the fossil fuel economy. We review the evidence of effects in five public health domains with a particular focus on the UK: exposure, health, socio-economic, climate change and seismicity. While the latter would seem not to be of significance for the UK, we conclude that serious gaps in our understanding of the other potential impacts persist together with some concerning signals in the literature and legitimate uncertainties derived from first principles. There is a fundamental requirement for high-quality epidemiological research incorporating real exposure measures, improved understanding of methane leakage throughout the process, and a rigorous analysis of the UK social and economic impacts. In the absence of such intelligence, we consider it prudent to incentivise further research and delay any proposed developments in the UK. Recognising the political realities of the planning and permitting process, we make a series of recommendations to protect public health in the event of hydraulic fracturing being approved in the UK.

A Review of the Human Health Impacts of Unconventional Natural Gas Development

PURPOSE OF REVIEW

This review summarizes the recent epidemiologic literature examining health outcomes in communities living close to unconventional natural gas development (UNGD) and identifies areas requiring further study.

RECENT FINDINGS

To date, these studies have been primarily retrospective in design and used self-report of health symptoms or electronic health databases to obtain outcome information. Proximity to UNGD is often used as a surrogate for exposure. There is preliminary evidence linking respiratory outcomes, including asthma exacerbations, and birth outcomes, such as reduced fetal growth and preterm birth, to UNGD; however, results differ across study populations and regions.

SUMMARY

Although small, the current body of literature suggests that living near UNGD may have negative health consequences for surrounding communities, but additional work using more granular estimates of exposure or personalized monitoring is urgently needed.

Childhood hematologic cancer and residential proximity to oil and gas development

Background

Oil and gas development emits known hematological carcinogens, such as benzene, and increasingly occurs in residential areas. We explored whether residential proximity to oil and gas development was associated with risk for hematologic cancers using a registry-based case-control study design.

Methods

Participants were 0–24 years old, living in rural Colorado, and diagnosed with cancer between 2001–2013. For each child in our study, we calculated inverse distance weighted (IDW) oil and gas well counts within a 16.1-kilometer radius of residence at cancer diagnosis for each year in a 10 year latency period to estimate density of oil and gas development. Logistic regression, adjusted for age, race, gender, income, and elevation was used to estimate associations across IDW well count tertiles for 87 acute lymphocytic leukemia (ALL) cases and 50 non-Hodgkin lymphoma (NHL) cases, compared to 528 controls with non-hematologic cancers.

Findings

Overall, ALL cases 0–24 years old were more likely to live in the highest IDW well count tertiles compared to controls, but findings differed substantially by age. For ages 5–24, ALL cases were 4.3 times as likely to live in the highest tertile, compared to controls (95% CI: 1.1 to 16), with a monotonic increase in risk across tertiles (trend p-value = 0.035). Further adjustment for year of diagnosis increased the association. No association was found between ALL for children aged 0–4 years or NHL and IDW well counts. While our study benefited from the ability to select cases and controls from the same population, use of cancer-controls, the limited number of ALL and NHL cases, and aggregation of ages into five year ranges, may have biased our associations toward the null. In addition, absence of information on O&G well activities, meteorology, and topography likely reduced temporal and spatial specificity in IDW well counts.

Conclusion

Because oil and gas development has potential to expose a large population to known hematologic carcinogens, further study is clearly needed to substantiate both our positive and negative findings. Future studies should incorporate information on oil and gas development activities and production levels, as well as levels of specific pollutants of interest (e.g. benzene) near homes, schools, and day care centers; provide age-specific residential histories; compare cases to controls without cancer; and address other potential confounders, and environmental stressors.

Unconventional oil and gas development and risk of childhood leukemia: Assessing the evidence

The widespread distribution of unconventional oil and gas (UO&G) wells and other facilities in the United States potentially exposes millions of people to air and water pollutants, including known or suspected carcinogens. Childhood leukemia is a particular concern because of the disease severity, vulnerable population, and short disease latency. A comprehensive review of carcinogens and leukemogens associated with UO&G development is not available and could inform future exposure monitoring studies and human health assessments. The objective of this analysis was to assess the evidence of carcinogenicity of water contaminants and air pollutants related to UO&G development. We obtained a list of 1177 chemicals in hydraulic fracturing fluids and wastewater from the U.S. Environmental Protection Agency and constructed a list of 143 UO&G-related air pollutants through a review of scientific papers published through 2015 using PubMed and ProQuest databases. We assessed carcinogenicity and evidence of increased risk for leukemia/lymphoma of these chemicals using International Agency for Research on Cancer (IARC) monographs. The majority of compounds (>80%) were not evaluated by IARC and therefore could not be reviewed. Of the 111 potential water contaminants and 29 potential air pollutants evaluated by IARC (119 unique compounds), 49 water and 20 air pollutants were known, probable, or possible human carcinogens (55 unique compounds). A total of 17 water and 11 air pollutants (20 unique compounds) had evidence of increased risk for leukemia/lymphoma, including benzene, 1,3-butadiene, cadmium, diesel exhaust, and several polycyclic aromatic hydrocarbons. Though information on the carcinogenicity of compounds associated with UO&G development was limited, our assessment identified 20 known or suspected carcinogens that could be measured in future studies to advance exposure and risk assessments of cancer-causing agents. Our findings support the need for investigation into the relationship between UO&G development and risk of cancer in general and childhood leukemia in particular.

Unconventional Natural Gas Development and Birth Outcomes in Pennsylvania, USA

BACKGROUND

Unconventional natural gas development has expanded rapidly. In Pennsylvania, the number of producing wells increased from 0 in 2005 to 3,689 in 2013. Few publications have focused on unconventional natural gas development and birth outcomes.

METHODS

We performed a retrospective cohort study using electronic health record data on 9,384 mothers linked to 10,946 neonates in the Geisinger Health System from January 2009 to January 2013. We estimated cumulative exposure to unconventional natural gas development activity with an inverse-distance squared model that incorporated distance to the mother's home; dates and durations of well pad development, drilling, and hydraulic fracturing; and production volume during the pregnancy. We used multilevel linear and logistic regression models to examine associations between activity index quartile and term birth weight, preterm birth, low 5-minute Apgar score and small size for gestational age birth, while controlling for potential confounding variables.

RESULTS

In adjusted models, there was an association between unconventional natural gas development activity and preterm birth that increased across quartiles, with a fourth quartile odds ratio of 1.4 (95% confidence interval = 1.0, 1.9). There were no associations of activity with Apgar score, small for gestational age birth, or term birth weight (after adjustment for year). In a posthoc analysis, there was an association with physician-recorded high-risk pregnancy identified from the problem list (fourth vs. first quartile, 1.3 [95% confidence interval = 1.1, 1.7]).

CONCLUSION

Prenatal residential exposure to unconventional natural gas development activity was associated with two pregnancy outcomes, adding to evidence that unconventional natural gas development may impact health.See Video Abstract at http://links.lww.com/EDE/B14.

Endocrine-Disrupting Chemicals and Oil and Natural Gas Operations: Potential Environmental Contamination and Recommendations to Assess Complex Environmental Mixtures

BACKGROUND

Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. Although these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals that are used throughout the process, including many known or suspected endocrine-disrupting chemicals.

OBJECTIVES

We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and antihormonal activities for chemicals used.

METHODS

We discuss the literature on a) surface and groundwater contamination by oil and gas extraction operations, and b) potential human exposure, particularly in the context of the total hormonal and antihormonal activities present in surface and groundwater from natural and anthropogenic sources; we also discuss initial analytical results and critical knowledge gaps.

DISCUSSION

In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures.

CONCLUSIONS

We describe a need for an endocrine-centric component for overall health assessments and provide information supporting the idea that using such a component will help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs.

All-age hospitalization rates in coal seam gas areas in Queensland, Australia, 1995-2011

Background

Unconventional natural gas development (UNGD) is expanding globally, with Australia expanding development in the form of coal seam gas (CSG). Residents and other interest groups have voiced concerns about the potential environmental and health impacts related to CSG. This paper compares objective health outcomes from three study areas in Queensland, Australia to examine potential environmentally-related health impacts.

Methods

Three study areas were selected in an ecologic study design: a CSG area, a coal mining area, and a rural/agricultural area. Admitted patient data, as well as population data and additional factors, were obtained for each calendar year from 1995 through 2011 to calculate all-age hospitalization rates and age-standardized rates in each of these areas. The three areas were compared using negative binomial regression analyses (unadjusted and adjusted models) to examine increases over time of hospitalization rates grouped by primary diagnosis (19 ICD chapters), with rate ratios serving to compare the within-area regression slopes between the areas.

Results

The CSG area did not have significant increases in all-cause hospitalization rates over time for all-ages compared to the coal and rural study areas in adjusted models (RR: 1.02, 95 % CI: 1.00–1.04 as compared to the coal mining area; RR: 1.01, 95 % CI: 0.99–1.04 as compared to the rural area). While the CSG area did not show significant increases in specific hospitalization rates compared to both the coal mining and rural areas for any ICD chapters in the adjusted models, the CSG area showed increases in hospitalization rates compared only to the rural area for neoplasms (RR: 1.09, 95 % CI: 1.02–1.16) and blood/immune diseases (RR: 1.14, 95 % CI: 1.02–1.27).

Conclusions

This exploratory study of all-age hospitalization rates for three study areas in Queensland suggests that certain hospital admissions rates increased more quickly in the CSG study area than in other study areas, particularly the rural area, after adjusting for key sociodemographic factors. These findings are an important first step in identifying potential health impacts of CSG in the Australian context and serve to generate hypotheses for future studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-2787-5) contains supplementary material, which is available to authorized users.

Environmental health impacts of unconventional natural gas development: a review of the current strength of evidence

Rapid global expansion of unconventional natural gas development (UNGD) raises environmental health concerns. Many studies present information on these concerns, yet the strength of epidemiological evidence remains tenuous. This paper is a review of the strength of evidence in scientific reporting of environmental hazards from UNGD activities associated with adverse human health outcomes. Studies were drawn from peer-reviewed and grey literature following a systematic search. Five databases were searched for studies published from January 1995 through March 2014 using key search terms relevant to environmental health. Studies were screened, ranked and then reviewed according to the strength of the evidence presented on adverse environmental health outcomes associated with UNGD. The initial searches yielded >1000 studies, but this was reduced to 109 relevant studies after the ranking process. Only seven studies were considered highly relevant based on strength of evidence. Articles spanned several relevant topics, but most focussed on impacts on typical environmental media, such as water and air, with much of the health impacts inferred rather than evidenced. Additionally, the majority of studies focussed on short-term, rather than long-term, health impacts, which is expected considering the timeframe of UNGD; therefore, very few studies examined health outcomes with longer latencies such as cancer or developmental outcomes. Current scientific evidence for UNGD that demonstrates associations between adverse health outcomes directly with environmental health hazards resulting from UNGD activities generally lacks methodological rigour. Importantly, however, there is also no evidence to rule out such health impacts. While the current evidence in the scientific research reporting leaves questions unanswered about the actual environmental health impacts, public health concerns remain intense. This is a clear gap in the scientific knowledge that requires urgent attention.

Environmental public health dimensions of shale and tight gas development

BACKGROUND

The United States has experienced a boom in natural gas production due to recent technological innovations that have enabled this resource to be produced from shale formations.

OBJECTIVES

We reviewed the body of evidence related to exposure pathways in order to evaluate the potential environmental public health impacts of shale gas development. We highlight what is currently known and identify data gaps and research limitations by addressing matters of toxicity, exposure pathways, air quality, and water quality.

DISCUSSION

There is evidence of potential environmental public health risks associated with shale gas development. Several studies suggest that shale gas development contributes to ambient air concentrations of pollutants known to be associated with increased risk of morbidity and mortality. Similarly, an increasing body of studies suggest that water contamination risks exist through a variety of environmental pathways, most notably during wastewater transport and disposal, and via poor zonal isolation of gases and fluids due to structural integrity impairment of cement in gas wells.

CONCLUSION

Despite a growing body of evidence, data gaps persist. Most important, there is a need for more epidemiological studies to assess associations between risk factors, such as air and water pollution, and health outcomes among populations living in close proximity to shale gas operations.

The role of toxicological science in meeting the challenges and opportunities of hydraulic fracturing

We briefly describe how toxicology can inform the discussion and debate of the merits of hydraulic fracturing by providing information on the potential toxicity of the chemical and physical agents associated with this process, individually and in combination. We consider upstream activities related to bringing chemical and physical agents to the site, on-site activities including drilling of wells and containment of agents injected into or produced from the well, and downstream activities including the flow/removal of hydrocarbon products and of produced water from the site. A broad variety of chemical and physical agents are involved. As the industry expands this has raised concern about the potential for toxicological effects on ecosystems, workers, and the general public. Response to these concerns requires a concerted and collaborative toxicological assessment. This assessment should take into account the different geology in areas newly subjected to hydraulic fracturing as well as evolving industrial practices that can alter the chemical and physical agents of toxicological interest. The potential for ecosystem or human exposure to mixtures of these agents presents a particular toxicological and public health challenge. These data are essential for developing a reliable assessment of the potential risks to the environment and to human health of the rapidly increasing use of hydraulic fracturing and deep underground horizontal drilling techniques for tightly bound shale gas and other fossil fuels. Input from toxicologists will be most effective when employed early in the process, before there are unwanted consequences to the environment and human health, or economic losses due to the need to abandon or rework costly initiatives.

Potential public health hazards, exposures and health effects from unconventional natural gas development

The rapid increase in unconventional natural gas (UNG) development in the United States during the past decade has brought wells and related infrastructure closer to population centers. This review evaluates risks to public health from chemical and nonchemical stressors associated with UNG, describes likely exposure pathways and potential health effects, and identifies major uncertainties to address with future research. The most important occupational stressors include mortality, exposure to hazardous materials and increased risk of industrial accidents. For communities near development and production sites the major stressors are air pollutants, ground and surface water contamination, truck traffic and noise pollution, accidents and malfunctions, and psychosocial stress associated with community change. Despite broad public concern, no comprehensive population-based studies of the public health effects of UNG operations exist. Major uncertainties are the unknown frequency and duration of human exposure, future extent of development, potential emission control and mitigation strategies, and a paucity of baseline data to enable substantive before and after comparisons for affected populations and environmental media. Overall, the current literature suggests that research needs to address these uncertainties before we can reasonably quantify the likelihood of occurrence or magnitude of adverse health effects associated with UNG production in workers and communities.