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Frontiers in Environmental Health ·

Volume 5 - 2026 | https://doi.org/10.3389/fenvh.2026.1905918

Patterns of environmental exposure-related documentation in emergency department visits within El Paso, Texas: a 25-year retrospective review

  • Aparna Mangadu1*corresponding author
  • Katherine Asmis2
  • Fernando Garza2
  • Scott B. Crawford1,3
  • Erica Guerrero3
  • Stormy M. Monks1,3
  1. 1Training and Educational Center for Healthcare Simulation, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
  2. 2Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
  3. 3Department of Emergency Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
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Abstract

El Paso, Texas, a city uniquely situated along the US-Mexico border, faces increased exposure to environmental pollutants due to factors including the mountainous desert landscape, industrial pollution, and high rates of transborder mobility along the El Paso-Juarez binational region. These unique environmental conditions and community characteristics make the region an important setting for environmental exposure surveillance. The association between traffic-related air pollution and adverse health outcomes is well established; however, the magnitude of impact that poor air quality and other environmental stressors place on border populations remains underexplored. Therefore, this study aimed to identify the most frequently documented environmental exposure-related ICD-9/10 codes among emergency department (ED) visits in El Paso and to characterize documentation patterns, temporal and seasonal trends, and selected healthcare utilization outcomes. The study retrospectively reviewed charts from ED visits at University Medical Center of El Paso (UMCEP) and El Paso Children's Hospital (EPCH) between January 2000 to December 2024, examining frequency, distribution, and longitudinal and seasonal trends of environmental exposure-related ED visits. Seven hundred and twenty-six charts met inclusion criteria for patients aged up to 89 years with at least one environmental exposure-related diagnostic code. The most frequently documented codes were Z77.098: Contact with and (suspected) exposure to other hazardous, chiefly nonmedicinal, chemicals, Z77.011: Contact with and (suspected) exposure to lead, and V15.89: Other specified personal history presenting hazards to health. Environmental exposure-coded ED visits increased notably between 2015 and 2016 and demonstrated seasonal variation, with higher counts in the summer months. These findings provide important insights to how environmental exposure-related ED visits are documented within the region, highlighting distinct temporal and seasonal patterns. However, the overwhelming use of non-specific exposure codes underscores a need for more granular documentation to better characterize environmental exposures and inform future surveillance strategies.

Keywords

Introduction

Global and national health impacts of environmental pollution

Environmental pollution is a major contributor to the global burden of disease, operating through increasingly frequent extreme weather events, complex exposure pathways, and gaps in understanding of emerging environmental risks (1–3). As environmental pollution becomes more prevalent and severe, healthcare utilization has increased worldwide, particularly through more frequent and recurring emergency department (ED) visits for a wide range of acute and chronic health conditions (4, 5). For example, ED visits have been linked to exposure to air pollutants such as wildfire smoke, vehicle exhaust, and industrial emissions, which contribute to respiratory morbidity and other adverse health outcomes (6, 7).

These health impacts have been documented across various populations but disproportionately affect vulnerable groups like children and older adults. Nationally, pediatric exposure to ambient air pollutants has been associated with increased ED visits for respiratory conditions such as asthma (8, 9). Similarly, elevated air pollution has been associated with increased ED visits among older adults for chronic respiratory conditions following periods of poor air quality. Although respiratory health remains the most extensively studied in relation to environmental pollution exposure, associations have been noted with adverse cardiovascular and mental health outcomes within vulnerable populations (10, 11).

The impact of environmental pollution on border region health

The health impacts of environmental pollution may be amplified in regions with rapidly growing populations, unique environmental conditions, and limited access to healthcare resources (12). In these settings, environmental pollution is associated with elevated rates of respiratory, gastrointestinal, cardiovascular, and reproductive diseases (13–15).

Within the United States, substantial population growth has occurred along the Texas/Mexico border region, with a population of over 2 million in 2025 (16). Poor air quality throughout this region is driven by the regional topography, arid conditions, and anthropogenic factors like transborder mobility and industrial emissions (17). El Paso County, located in western Texas along the US/Mexico border, experiences particularly high levels of traffic-related air pollution, with an estimated 14–17 million vehicles crossing the El Paso-Juarez border annually (18). In addition to poor air quality, the El Paso-Juarez binational region faces compromised water and soil quality due to both natural and anthropogenic drivers (19, 20). Historically, these environmental burdens have been compounded by industrial activity such as the operation of metal smelters, which substantially contributed to heavy metal contamination of the soil, water, and air (21). As a result, residents in this region, especially children, have consistently demonstrated elevated blood lead levels (22).

Current knowledge and existing research gap

Investigations conducted in countries with substantial environmental pollution, including China, Canada, and Japan, have consistently demonstrated associations between poor environmental conditions and increased emergency department utilization for respiratory and nervous system diseases as well as mental health outcomes (23–26). Similar associations have been reported within the United States (27). Despite this growing body of evidence, there is an incomplete understanding of the extent of climate pollution and how environmental exposures are documented during ED encounters within US/Mexico border communities. Additionally, little is known about how routinely collected healthcare data may support environmental health surveillance in these regions.

This knowledge gap is particularly relevant in the El Paso-Juarez border region, where environmental monitoring resources remain limited despite growing and persistent environmental challenges. Although concerns of air pollution, heavy metal exposure, and transborder vehicle emissions are well-documented for this region (28, 29), few studies have characterized environmental exposure-related healthcare encounters using routine clinically documented information (17, 30). Furthermore, emergency room overcrowding due to inadequate staffing, bed shortages, and nonurgent visits (31), is prevalent in this medically underserved region (17), likely contributing to poor patient outcomes. These healthcare challenges may also potentially limit timely recognition and management of environmentally related illnesses. Therefore, improved characterization of environmental exposure-related healthcare encounters may provide valuable information for regional environmental surveillance and healthcare planning.

Study motivation and objective

To improve understanding of how environmental exposure-related diagnoses are documented during emergency department visits and identify patterns that may inform future environmental health surveillance, baseline data can be established using ICD-9/10 codes. Previous studies have successfully employed this approach to inform healthcare providers of the impacts of environmental exposure on health outcomes in specific regions (32). In particular, several ICD codes reflect provider recognition and documentation of suspected or confirmed environmental exposures which can then be used to link with illnesses potentially attributable to environmental factors. The purpose of this study was to identify the most common environmental exposure-related ICD-9/10 codes documented during emergency department visits within two healthcare facilities in El Paso across a 25-year period, and to characterize clinical documentation patterns, seasonal and longitudinal trends, and selected healthcare utilization outcomes, including emergency department disposition and repeat visits.

Materials and methods

Study setting & design

This study was a retrospective chart review of emergency department (ED) visits with clinical documentation of confirmed or suspected environmental exposure from two healthcare facilities in El Paso, Texas, University Medical Center of El Paso (UMCEP) and El Paso Children's Hospital (EPCH). Within 200 miles, UMCEP Emergency Medicine Department is the only level one trauma center and El Paso Children's Hospital is the only children's hospital. UMCEP and El Paso Children's Hospital predominately service a Hispanic population. Visits for patients aged less than 89 years and occurring between January 1, 2000 and December 31, 2024 were eligible for inclusion). The environmental exposure-related ICD-9/10 codes used to identify eligible encounters are listed in Table 1. The code list was developed through consultation with core team members of the Pediatric Environmental Health Specialty Unit (PEHSU) Region 6 and refined through expert consensus based on coding practices routinely used in participating local emergency departments. Other potentially relevant environmental exposure codes were excluded as they were not considered by the PEHSU consultation group to represent environmental exposure-related encounters relevant to the region or study objectives.

Table 1. Inclusion criteria.

CategoryInclusion Criteria
ICDa-9/10 CodesEDb visit with one or more of the following codes
Z77.11cContact with and (suspected) exposure to environmental pollution
Z77.110Contact with and (suspected) exposure to air pollution
Z77.111Contact with and (suspected) exposure to water pollution
Z77.112Contact with and (suspected) exposure to soil pollution
Z77.118cContact with and (suspected) exposure to other environmental pollution
Z77.011Contact with and (suspected) exposure to lead
Z77.018cContact with and (suspected) exposure to other hazardous metals
Z77.098cContact with and (suspected) exposure to other hazardous, chiefly nonmedicinal, chemicals
V15.89cOther specified personal history presenting hazards to health
V87.0Contact with and (suspected) exposure to hazardous metals
V87.1Contact with and (suspected) exposure to hazardous aromatic compounds
V87.2cContact with and (suspected) exposure to other potentially hazardous chemicals
V87.39cContact with and (suspected) exposure to other potentially hazardous substances
985.9cToxic effect of unspecified metal
Patient AgePatients aged ≤ 89

ICD, International Classification of Diseases.

ED, Emergency Department.

ICD codes that may reflect non-specific environmental or hazard-related dodumentation.

Data sources & data collection

Data was extracted from electronic health records (EHRs) obtained from each institution by institutional research support personnel (Figure 1). Using the IRB-approved inclusion criteria, database queries identified ED encounters occurring between January 1, 2000 and December 31, 2024 that contained at least one of the predefined environmental exposure-related ICD codes. Record identification only relied on these predefined inclusion criteria and did not include keyword searches or free-text screening. The resulting dataset was exported to a secure, password-protected REDCap database with patient identifiers, such as medical record numbers (MRNs), removed prior to analysis to protect patient confidentiality.

Flowchart of data collection methods.
Figure 1. Flowchart of data collection methods.

Variables and outcomes

Demographic variables of interest included sex, age, race, and ethnicity. Clinical characteristics included chief complaint, ED disposition, and documented follow-up. The primary outcome of interest was the environmental exposure-related ICD-9 or ICD-10 code assigned to each ED visit. These codes represent provider documentation of confirmed or suspected environmental exposures rather than direct measures of environmental exposure, exposure level, or exposure source. Accordingly, this study only captures ED encounters in which providers documented at least one predefined environmental exposure-related ICD code (Table 1). Secondary healthcare utilization outcomes of interest were final disposition and readmission for re-exposure. Readmission for re-exposure was determined using the MRNs and visit dates provided to identify patients with multiple visits for confirmed or suspected environmental exposure. In cases of readmission for re-exposure, multiple visits from the same patient were analyzed independently.

Data analysis

Data analysis was conducted in R Studio (version 4.4.1). Descriptive statistics were used to summarize demographic and clinical characteristics of included patient records. Continuous variables were summarized using means, medians, modes, and interquartile ranges. Categorical variables were summarized using frequencies and percentages. Descriptive statistics were further compared across age group, sex, and facility using Pearson chi-square tests to characterize differences in the distribution of the most frequently documented ICD codes.

To evaluate temporal trends, annual counts of environmental exposure-elated ICD-coded ED visits were analyzed separately for the ICD-9 and ICD-10 coding eras using a nonparametric Mann-Kendall trend test to account for the transition from ICD-9 to ICD-10 coding in October 2015. Seasonality was assessed by fitting a Poisson regression model with month of admission as the predictor and monthly visit counts as the outcome. Statistical significance was defined as a two-sided p-value <0.05.

Results

Across the assessed twenty-five-year time period, 726 emergency encounters met the predefined inclusion criteria with a total of 678 individual patients (Table 2). Study subjects were primarily White (70.9%), and Hispanic (86.7%) consisting of both females (50.4%) and males (49.6%). The average age of the subjects was 28.7 years. More than half of the included records were from UMCEP (63.9%).

Table 2. Demographics.

CharacteristicdRecords (n = 726)
Patients (n = 678)e
Sex, n (%)
Female342 (50.4)
Male336 (49.6)
Age, years
Mean (Range)28.7 (0–88)
Median (IQRa)25 (6–49)
Mode2
Race, n (%)
White481 (70.9)
Black18 (2.7)
American Indian2 (0.3)
Asian4 (0.6)
Other/Unknown173 (25.5)
Ethnicity, n (%)
Hispanic588 (86.7)
Non-Hispanic89 (13.1)
Unknown1 (0.1)
Location, n (%)
UMCEPb464 (63.9)
EPCHc262 (36.1)

IQR, Interquartile Range.

UMCEP, University Medical Center of El Paso.

EPCH, El Paso Children's Hospital.

Values are presented as counts, percentages, means, medians, or interquartile ranges as appropriate.

Counts of records and patients are reported separately because some individuals had repeat visits.

Healthcare utilization outcomes examined included primary patient disposition and readmission for re-exposure to environmental factors. The primary disposition outcome among study subjects was routine discharge to the home (Table 3). Few subjects were transferred to other facilities including psychiatric, correctional, and long-term care. Of the 678 subjects, 41 were readmitted for re-exposure with 2 to 3 total ED visits each.

Table 3. Clinical outcomes.

OutcomeaRecords (n = 726)
Patients (n = 678)b
Readmitted, n (%)
Yes41 (6.05)
No637 (93.9)
Disposition, n (%)
Home/Routine Discharge599 (82.5)
Skilled Nursing/Rehab/Long-Term Care3 (0.4)
Transfer to Other Facility6 (1.0)
Psychiatric Transfer1 (0.1)
Correctional Facility Transfer3 (0.4)
Left Against Medical Advice19 (2.6)
Other/Unknown95 (13.1)

Values are presented as counts, percentages, means, medians, or interquartile ranges as appropriate.

Counts of records and patients are reported separately because some individuals had repeat visits.

The most frequently documented environmental exposure-related ICD code was Z77.098: Contact with and (suspected exposure to other hazardous, chiefly nonmedicinal, chemicals (n = 272), followed by Z77.011: Contact with and (suspected) exposure to lead (n = 177), and V15.89: Other specified personal history presenting hazards to health (n = 175) (Figure 2). The ICD-9 code V15.89 is typically used to categorize a patient as having a previous condition or hazardous exposure that may result in adverse health outcomes later on, even if the patient is not presently ill. Conversely, the least frequently documented codes were 985.9: Toxic effect of unspecified metal (n = 1), Z77.110: Contact with and (suspected)e exposure to air pollution (n = 1), and Z77.118: Contact with and (suspected) exposure to other hazardous, chiefly nonmedicinal, chemicals (n = 5). Five environmental exposure-related ICD codes were not observed: Z77.11: Contact with and (suspected) exposure to environmental pollution, Z77.111: Contact with and (suspected) exposure to water pollution, Z77.112: Contact with and (suspected) exposure to soil pollution, V87.0: Contact with and (suspected) exposure to hazardous metals, and V87.1: Contact with and (suspected) exposure to hazardous aromatic compounds.

Top environmental exposure ICD codes by number of emergency department (ED) visits, highlighting Z77.098 and Z77.011 as the most frequently recorded exposure-related diagnoses.
Figure 2. Top environmental exposure ICD codes by number of emergency department (ED) visits, highlighting Z77.098 and Z77.011 as the most frequently recorded exposure-related diagnoses.

ICD code distributions differed significantly between pediatric and adult patients (p≤ 0.001). Pediatric encounters were disproportionately represented by ICD-10 codes Z77.011 (n = 167) and Z77.098 (n = 57), while adult encounters were more frequently documented with ICD-10 code Z77.098 (n = 215) and ICD-9 code V15.89 (n = 126). Similarly, ICD code distributions differed significantly by facility (p < 0.001), with more frequent documentation of ICD-10 code Z77.011 at EPCH (n = 153), ICD-10 code Z77.098 at UMCEP (n = 234), and ICD-9 code V15.89 and UMCEP (n = 130). Significant differences were also observed by sex with higher documentation in females for ICD-9 code V15.89 (67.4%), whereas males exhibited higher documentation of ICD-10 codes Z77.098 (56.3%) and Z77.011 (54.2%).

When stratified by ICD coding system, ICD-9 coded environmental exposure-related ED visits gradually increased from 2000 through 2014, whereas ICD-10 codes visits were first observed following national implementation of the ICD-10 coding system in 2015 (Figure 3A). ICD-9 coded visits demonstrated a significant increasing monotonic trend over time (Mann-Kendall tau = 0.744, p < 0.001). For ICD-10 codes, the highest number of coded visits occurred in 2016, after which annual counts remained relatively stable with slight year-to-year variation, but these trends were not significant (Mann-Kendall tau = −0.156, p = 0.592). Facility-specific trends demonstrated that the increase in ICD-10 coded visits during 2015–2016 was largely driven by pediatric encounters at EPCH (Figure 3B). Among individual ICD-10 codes, Z77.011 (lead exposure) had particularly high documented ED visits during the early ICD-10 coding system implementation period (Figure 3C).

Temporal trends in emergency department (ED) visits associated with environmental exposure ICD codes over the study period: **(A)** total ED visit counts over time stratified by coding era, **(B)** ED visit counts stratified by facility (EPCH and UMC EP), and **(C)** heatmap of ED visits by specific ICD codes across time. Statistical significance for Figure 2A of temporal trends was assessed using Mann-Kendall trend tests separately for the ICD-9 and ICD-10 coding eras.
Figure 3. Temporal trends in emergency department (ED) visits associated with environmental exposure ICD codes over the study period: (A) total ED visit counts over time stratified by coding era, (B) ED visit counts stratified by facility (EPCH and UMC EP), and (C) heatmap of ED visits by specific ICD codes across time. Statistical significance for Figure 2A of temporal trends was assessed using Mann-Kendall trend tests separately for the ICD-9 and ICD-10 coding eras.

To provide additional context for temporal trends, annual environmental exposure-related ED visit rates were calculated for UMCEP using available annual ED visit total (Supplementary Table S1). From 2009 to 2024, environmental-exposure coded visit rates increased from 0.29 to 0.83 per 1,000 ED visits, with slight year to year variation and relatively stable annual ED volumes. In a Poisson regression model with annual ED visits included as an offset, the rate of environmental exposure-related coded ED visits increased significantly over time (incidence rate ratio = 1.045 per year, 95% CI: 1.023–1.068; p < 0.001), corresponding to an average annual increase of approximately 4.5% after accounting for annual ED volume.

Seasonal trends reveal an increase in overall environmental exposure coded ED visits in the summer months between July to September (Figure 4A). Of the identified codes Z77.098 (hazardous substances) and Z77.011 (lead exposure) appear to have the highest number of associated ED visits during these months (Figure 4B). Monthly variation in environmental exposure-related ICD coded ED visits was statistically significant (Poisson regression likelihood ratio = 29.32, p = 0.002), supporting the presence of seasonal variation in the documented encounters.

Seasonal patterns in emergency department (ED) visits associated with environmental exposure ICD codes: **(A)** overall monthly ED visit counts and **(B)** heatmap of ED visits by ICD code across months. Monthly counts of environmental exposure-related ICD-coded visits were aggregated across study years. Overall seasonal variation was evaluated using a Poisson regression model with month of admissions as the predictor.
Figure 4. Seasonal patterns in emergency department (ED) visits associated with environmental exposure ICD codes: (A) overall monthly ED visit counts and (B) heatmap of ED visits by ICD code across months. Monthly counts of environmental exposure-related ICD-coded visits were aggregated across study years. Overall seasonal variation was evaluated using a Poisson regression model with month of admissions as the predictor.

Discussion

Exposure to environmental hazards, such as air and water pollution, are a globally recognized contributor to adverse health outcomes. However, less is known about the specific impacts of exposure on border communities, like El Paso, Texas, where environmental pollution is often intensified due to a variety of and unique sources. The purpose of this study was to retrospectively examine ED visit records in El Paso, Texas to characterize patterns in environmental exposure-related ICD 9/10 diagnoses documented during emergency department visits.

Lead and hazardous chemical exposure documentation in El Paso

Confirmed and suspected exposure to hazardous, chiefly nonmedicinal, chemicals and lead were identified as the top environmental exposure-related ICD-10 codes for ED visits from 2000 to 2024. Additionally, the ICD-9 code indicating personal exposure history was among the most frequently used codes as well. Lead exposure, as indicated by ICD-10 code Z77.011, is unsurprising for the region as El Paso is recognized to have higher historical environmental lead contamination (21, 22). This presents a particularly high health risk for children in this region as they have been shown to have higher blood lead levels than their rural counterparts (33). Exposure to hazardous chemicals and air toxicants like bisphenols, phthalates, carbonyls, and PAHs and the associated health impacts is also well documented in this region (34–37). However, the limited specificity of ICD-10 code Z77.098 makes it difficult to determine individual chemicals resulting in increased ED visits.

Temporal changes in environmental exposure-related ED documentation

Longitudinally and when stratified by ICD coding era, this study identified an apparent increase in environmental exposure-related ED visits beginning in 2015 which coincides with the national transition from ICD-9 to ICD-10 standardized coding (38). Accordingly, this increase likely partially reflects changes in coding practices and the introduction of new ICD-10 environmental exposure codes rather than a true increase in environmental exposures alone (39). This finding may also demonstrate the increased specificity of ICD-10 coding categories and ability to include environmental contributors and location to otherwise independent diagnosis codes. However, supplementary analysis using available annual denominator data from UMCEP demonstrated that environmental exposure-related coded ED visit rates increased significantly over time from 2009 to 2024, even after accounting for annual ED utilization. This suggests that the observed increase may at least be moderately attributable to increases in recognized environmental exposures.

Within the ICD-10 coding introduction period, code Z77.011 for lead exposure remained one of the most frequently documented codes especially among pediatric visits, consistent with regional trends in pediatric lead exposure burden. El Paso County is a high risk region for pediatric lead exposure in Texas with 1.79% in 2015 (40) and 2.08% in 2016 (41) of children tested having elevated blood lead levels. This observation could also be partially explained by the national shift to focus on lead exposure following the start of the Flint Water Crisis in 2014 (42), ultimately resulting in increased lead toxicity testing nationwide.

Seasonal patterns in environmental exposure-coded visits

This study also identified statistically significant seasonal variation in environmental exposure-related ICD-coded ED visits. Summer months, particularly June through September, had the highest counts of environmental exposure coded ED visits. Regarding pediatric lead exposure, previous research has found that these rates are often higher in the summer (43, 44). Other hazardous substances, like chemical releases, also often occur more in the summer months (45). This is especially true in Texas where adverse weather conditions such as rain and high winds occurring in the summer months significantly contribute to hazardous substance exposure (46).

Study strengths and implications

This study has several important strengths. First, it examined ED visits over a 25-year period in a medically underserved border region, providing a comprehensive assessment of environmental-exposure documentation for this understudied and environmentally burdened population. Second, the data included both a major adult county hospital and the region's primary children's hospital, allowing examination of environmental documentation across the lifespan with appropriate representation of the population. Additionally, the results of this investigation highlight current practices, gaps, and areas for improvement in regional environmental health surveillance and documentation approaches.

The findings from this study provide important insights for how environmental exposures are documented in the El Paso-Juarez border region. It is clear that non-specific ICD-9/10 codes like V15.89 and Z77.098 are commonly used within the emergency departments in both the main and children's hospital. While the large use of these codes indicates that interventions are needed to mitigate and reduce chemical and other hazardous exposures, it is unclear which specific chemicals should be the focus of such public health initiatives. Therefore, this study underscores a need for either more granular diagnostic coding or the creation of subcodes to complement the existing ICD 9/10 codes and strengthen environmental health surveillance and future epidemiologic research.

Limitations and future research needs

As with any retrospective review, there are limitations to consider. First, this study focused on just two healthcare facilities in the region, indicating possible selection bias. Although these facilities provide healthcare services for majority of the population, other regional hospitals may be documenting different environmental exposures. This may be true for lower-resource neighborhoods where barriers to access the facilities included in this study might exist. The data collection methods also did not account for provider notes. Charting and visit notes may include additional information for highlighting specific environmental exposures sometimes obtained during patient-provider discussion. A future strengthened analysis of ICD-10 codes will need to examine healthcare provider notes to include a more robust description of each ED visit. Additionally, many environmental exposures may lead to chronic medical conditions not leading to emergency department presentation and evaluation, so the burden of environmental health conditions may be underrepresented in this study.

Another important limitation is that ICD-9/10 codes reflect provider documentation of confirmed or suspected environmental exposures rather than direct measurements of environmental exposures and associated sources. Consequently, the study did not investigate confirmed environmental exposure measurements. The observed temporal and seasonal trends may also reflect changes in coding practices over time. Therefore, these findings should be interpreted as describing clinical documentation patterns rather than true regional environmental exposure burden. Additionally, patients presenting with illnesses potentially associated with environmental exposure such as asthma and COPD were not identified in this study if they did not have an accompanying environmental exposure ICD code. As a result, the study population may not represent all patients in the region with significant environmental exposure histories. Further, the patterns observed in this study do not reflect the true incidence of environmentally related disease within the region. Although supplementary analyses incorporating annual emergency department visit counts from UMCEP demonstrated increasing rates of environmental related ED visits over time after accounting for annual ED volume, comparable data was not available from EPCH and for years prior to 2009. As a result, environmental exposure-related ED visit rates could not be calculated across the entire study period, and the supplementary analysis should be interpreted as UMCEP specific. Future investigations should consider ICD codes for illnesses commonly associated with environmental exposures along with the environmental exposure codes identified in this study. Lastly, few of the codes analyzed, like V15.89, may not be definitely linked to environmental exposures as some older diagnostic codes were often used as a catch-all code for several health indicators.

Conclusions

Overall, this study provides one of the first long-term characterizations of provider-documented environmental exposure-related diagnoses among emergency department visits in the El Paso-Juarez border region. While lead exposure remained the most frequently documented environmental exposure, consistent with historical documentation, this study highlights the predominance of nonspecific ICD codes for other environmental exposures and underscores opportunities for improving specificity of clinical documentation. Significant temporal and seasonal trends provide preliminary insights for key timepoints for future exposure mitigation interventions and support the use of ICD-coded clinical data as a complementary tool for environmental health surveillance. This strategy can be expanded to support other medically underserved border communities.

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Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fenvh.2026.1905918/full#supplementary-material

Supplementary material Supplementary material at the source

Footnotes

Edited by: Rakesh Kumar, Auburn University, United States

Reviewed by: Najm Alsadat Madani, University at Albany, State University of New York, United States

Putri Nilam Sari, Universitas Andalas, Indonesia

Statements

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Funding

The author(s) declared that financial support was not received for this work and/or its publication.

Data availability

The data analyzed in this study is subject to the following licenses/restrictions: The data that support the findings of this study contain protected health information (PHI) and are not publicly available due to privacy and institutional restrictions. Data were obtained from University Medical Center of El Paso and El Paso Children's Hospital and are not available for sharing. De-identified data may be made available from the corresponding author upon reasonable request and with appropriate institutional approvals. Requests to access these datasets should be directed to Aparna Mangadu, Aparna.Mangadu@ttep.edu.

Ethics approval

This study involving humans were approved by Texas Tech University Health Sciences Center El Paso Institutional Review Board (E25118). This study was conducted in accordance with the local legislation and institutional requirements. The ethics committee/institutional review board waived the requirement of written informed consent for participation from the participants or the participants' legal guardians/next of kin because This is a retrospective review involving minimal risk. Waiver of consent was deemed appropriate.

Author contributions

AM: Formal analysis, Visualization, Writing – original draft, Writing – review & editing. KA: Data curation, Methodology, Writing – review & editing. FG: Data curation, Methodology, Writing – review & editing. SC: Conceptualization, Resources, Supervision, Writing – review & editing. EG: Investigation, Writing – review & editing. SM: Conceptualization, Investigation, Methodology, Project administration, Resources, Supervision, Writing – review & editing.

Acknowledgements

We would like to thank the University Medical Center of El Paso and El Paso Children's Hospital for granting access to the data used in this retrospective chart review. This study was reviewed and approved by the Institutional Review Board of Texas Tech University Health Sciences Center El Paso (IRB #250118).

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Citation

Mangadu, A., et al. (2026). Patterns of environmental exposure-related documentation in emergency department visits within El Paso, Texas: a 25-year retrospective review. Frontiers in Environmental Health, Volume 5. https://doi.org/
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5 - 2026

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© 2026 Mangadu, Asmis, Garza, Crawford, Guerrero and Monks.

License: https://creativecommons.org/licenses/by/4.0/

*Correspondence: Aparna Mangadu

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