Environmental Justice Analysis of Oil Extraction in Los Angeles Communities

Introduction

There are about 101,000 unplugged oil and gas wells in California, with about 8,000 (8%) located in Los Angeles County. The literature shows that oil and gas operations present an environmental health hazard to communities, directly relational to the proximity to and density of operational oil and gas wells. Namely, oil and gas extraction has been associated with respiratory, cardiac, neurologic, and pulmonary effects, as well as pediatric cancer, preterm birth, and mental health harms.1 Research specific to California also shows that oil and gas drilling operations have historically targeted marginalized communities. This analysis builds upon that statewide research and reveals the compounding environmental and socioeconomic burdens imposed by proximity to oil and gas wells borne by frontline communities in Los Angeles County.

While previous analyses of California have provided statewide estimations of demographics for those living closest to and most impacted by oil and gas extraction, this work takes a more community focused and intersectional approach to first define the communities most impacted, and then focus on multiple indicators of disparity in addition to race and ethnicity, such as socioeconomic status, educational attainment, age, and exposure to other pollution sources. This approach locates the environmental justice impacts of oil and gas extraction within existing, compounding frameworks of inequity. Additionally, we utilized a more comprehensive estimate of risk from exposure to oil and gas extraction by accounting for well density rather than solely proximity, and then locate the environmental justice impacts of oil and gas extraction within existing, compounding frameworks of inequity. 

We conducted a countywide assessment analyzing the demographics and existing environmental burden of urban communities living near high density oil and gas operations in Los Angeles County. While this countywide analysis does summarize the environmental justice issues present throughout the county as a whole, we direct the majority of our analysis to identifying the discrete communities within and surrounding individual urban oil and gas fields to focus on the areas where exposures to uncontrolled emissions from oil and gas extraction presents the greatest risk scenarios in the county. We then screened each community to evaluate intersectional environmental justice concerns. We also characterized the presence of oil and gas extraction operations, providing well statuses of unplugged wells and estimations of average distances between homes and wellhead locations. Because there were not the resources to focus on every oil and gas field in the county, specific communities where organizing efforts have been directed towards the phaseout of existing oil and gas fields were prioritized.

In this environmental justice proximity analysis, we compared the public health, environmental, demographic, and socioeconomic profiles of the sites of interest against the remainder of Los Angeles County. We utilized the CalEnviroScreen (CES) environmental justice screening tool to summarize environmental inequities. We compared CES scores between case and control Census Block Groups (CBGs). The results revealed that CES scores for communities located among the urban oil fields of Los Angeles County are elevated above both state and Los Angeles County averages. We summarized additional US Census Bureau (USCB) data to more accurately define the frontline communities, and compare community demographics to the countywide background population.

Methods

We utilized CES 4.0 and USCB 2020 Decennial Census results to investigate the intersectionality of disparate impacts of environmental threats and socio-economic vulnerabilities with the co-location of urban oil and gas fields in Los Angeles County. We extracted the locations of oil and gas wells from the California Department of Geological Energy Management (CalGEM) “AllWells” dataset. We used Esri ArcGIS geographical information systems (GIS) software, ArcGIS Pro 3.3.0, to map data. We used the Python 3.11.7 programming language to clean, manage, aggregate and summarize data.

CalEnviroScreen 4.0

CES is a publicly available mapping tool produced by the California Office of Environmental Health Hazard Assessment (OEHHA). CES was last updated in October of 2021. CES can be used by policymakers and researchers to determine which communities are most affected by, and vulnerable to, pollution in California. CES is conducted at the Census tract level and calculates scores to reflect pollution exposure and population vulnerabilities and allow for comparisons across tracts. Data is sourced from the EPA, USCB, and other government agencies for the years 2013-2021. The Population Characteristics score takes a weighted average of the sensitive populations and socioeconomic components such as the population of asthmatics, those who are linguistically isolated, those who are impoverished, or those with low educational attainment. The Pollution Burden score takes a weighted average of the environmental effects and exposures components such as presence of toxic releases, air quality indices, and traffic proximity. The final CES score is calculated by multiplying the Population Characteristics score and the Pollution Burden score. All three of these scores are described for each site below.

CES lists each Census tracts’ score from highest to lowest to determine the percentile each tract is categorized within and enable comparisons across the tracts. A higher score indicates more vulnerability and/or presence of environmental exposures. We selected a few CES indicators for the comparisons on this study, which are listed in the results below (Tables 1-8). For all the CES indicators used in the comparisons for this analysis, Los Angeles County scores were higher than the state averages. Therefore comparisons were made to the elevated county CES score (Table 1), rather than the statewide average, (50th percentile).

We allocated Los Angeles County CES percentile data from the Census Tract level to the CBG level under the assumption of normal distribution of the data. Working with CBG level data allows for more precise estimates of communities than provided by the tract level (Figure 2). Due to data privacy concerns, the USCB does not release data at the CBG level. Thus, the CBG level is the most granular scale researchers can use when working with demographic data.

Figure 2. Breakdown of USCB geographies.

We then merged CBG level CES data to 2020 Decennial Census and 2020 American Community Survey CBG level data. This final dataset allowed for CBG level comparisons of public health, environmental, demographic, and socioeconomic data for Los Angeles County. 

We used the ArcGIS Point Density tool to create a raster dataset of unplugged well density across Los Angeles County. We sourced well location data from the California Geologic Energy M​anagement Division. We overlaid this raster dataset with Los Angeles CBG boundaries and CBGs were manually selected based on two criteria: (1) the presence of high well density and/or (2) the known location of wells, unplugged or plugged, in the area. The CBGs identified as impacted by high densities of oil and gas wells are shown in the maps below, outlined in red, and can be considered case populations. Comparisons between the impacted CBGs (case populations) and the rest of Los Angeles County (control populations) are discussed for each site. When discussing the rest of Los Angeles County, we define the control population as the CBGs that do not contain high well densities, countywide.