Environmental Forensic Investigation of Industrial Plastic Fire Emissions, Air Dispersion Modeling, and Community Exposure Assessment
Project Overview
This environmental forensic investigation evaluated the environmental impacts associated with a large industrial plastics fire and the subsequent release of combustion byproducts into surrounding residential communities. The investigation integrated environmental engineering, atmospheric science, air dispersion modeling, environmental monitoring, and exposure assessment to reconstruct historical air pollutant concentrations and evaluate the movement of smoke, particulate matter, and combustion gases following the fire. Historical records, regulatory documents, air monitoring data, engineering analyses, and scientific literature were collectively reviewed to develop a scientifically defensible understanding of contaminant transport and potential community exposure.
Unlike routine industrial emissions, large uncontrolled fires generate rapidly changing emission rates and complex mixtures of combustion products that vary according to fuel composition, fire intensity, meteorological conditions, and suppression activities. Evaluating these incidents requires integration of multiple independent technical disciplines, including combustion science, atmospheric transport, environmental chemistry, exposure assessment, and environmental forensics. By combining these methods, investigators reconstructed historical environmental conditions despite the limited availability of direct measurements during portions of the incident.
The investigation also compared modeled concentrations with air monitoring data collected by multiple organizations, reviewed resident observations regarding smoke, ash, odors, and health effects, and evaluated regulatory documentation describing the incident. Integrating these independent datasets provided multiple lines of evidence supporting reconstruction of community exposures while reducing uncertainty associated with retrospective environmental investigations.
Chemicals of Concern
The primary contaminants evaluated during the investigation were fine particulate matter (PM₂.₅), coarse particulate matter (PM₁₀), nitrogen oxides (NOₓ), and other combustion-related air pollutants generated during the burning of polyethylene plastics and associated combustible materials. Fine particulate matter represented the principal contaminant of concern because it can remain suspended in the atmosphere for extended periods, travel significant distances from the fire, penetrate deeply into the respiratory system, and serve as a transport medium for other combustion-derived contaminants.
Nitrogen oxides were also evaluated because they are commonly generated during high-temperature combustion and contribute to respiratory irritation, ozone formation, and secondary particulate formation. Additional combustion products considered during the investigation included volatile organic compounds (VOCs), combustion gases, soot, ash, and odor-causing compounds associated with incomplete combustion. These contaminants collectively influence both air quality and community exposure during large industrial fire events.
The investigation further considered the physical behavior of smoke plumes generated during combustion. Smoke consists of a complex mixture of gases and particulate matter that changes continuously throughout a fire as combustion efficiency, fuel characteristics, and suppression activities evolve. Understanding this changing composition is essential for accurately reconstructing historical exposure conditions and evaluating contaminant transport.
Published scientific literature describing combustion emissions, particulate transport, atmospheric chemistry, and inhalation exposure was reviewed to provide context for interpreting monitoring data and atmospheric modeling results.
Methods
The investigation employed a multidisciplinary environmental forensic methodology integrating historical document review, engineering analyses, air dispersion modeling, environmental monitoring, geographic information systems (GIS), and exposure assessment. Historical records describing the fire timeline, fire suppression activities, facility operations, regulatory investigations, meteorological conditions, and environmental monitoring were reviewed to reconstruct conditions throughout the incident. Available engineering documentation describing burned materials and combustion characteristics was also incorporated into emissions reconstruction.
Atmospheric transport of combustion emissions was evaluated using AERMOD, the regulatory air dispersion model recommended by the U.S. Environmental Protection Agency for estimating pollutant transport from stationary and area sources. Source terms were developed using engineering calculations describing combustion emissions together with information regarding burned material quantities, combustion duration, meteorological conditions, and particle deposition characteristics. Multiple receptor grids, terrain information, and meteorological datasets were incorporated to characterize pollutant concentrations throughout surrounding residential areas.
Air monitoring information collected by federal, state, and independent monitoring programs was evaluated alongside modeled concentrations. Monitoring included particulate measurements, nitrogen oxide concentrations, continuous ambient monitoring stations, and supplemental field sampling. Comparing measured air quality data with modeled concentrations provided an independent means of evaluating model performance and refining interpretation of atmospheric transport.
The investigation also reviewed geographic distributions of smoke, ash deposition, and modeled particulate concentrations using GIS mapping techniques and concentration contour analyses. Hourly concentration animations and deposition mapping were used to visualize changing plume behavior throughout the duration of the incident and to evaluate how meteorological conditions influenced contaminant movement across surrounding communities.
Community observations provided additional information regarding environmental conditions experienced during and immediately following the fire. Resident declarations describing smoke density, ash deposition, persistent odors, visibility impairment, and acute symptoms were reviewed alongside atmospheric modeling results. While qualitative observations are not substitutes for quantitative environmental measurements, they provide useful contextual information that can be compared with modeled plume movement and environmental monitoring data.
Scientific literature addressing combustion chemistry, atmospheric transport, particulate deposition, odor transport, and inhalation exposure was incorporated throughout the investigation to support interpretation of environmental monitoring results and reconstructed exposure conditions.
Results
The investigation demonstrated that combustion emissions generated during the industrial plastics fire dispersed over surrounding residential communities under changing meteorological conditions throughout the incident. Air dispersion modeling illustrated the temporal and spatial variability of smoke plumes, with pollutant concentrations shifting as wind direction, atmospheric stability, and combustion conditions evolved. Hourly concentration mapping and animation provided a detailed representation of plume movement and potential exposure throughout the duration of the event.
Comparison of modeled concentrations with available monitoring information demonstrated reasonable agreement between predicted plume movement and measured air quality conditions. Independent monitoring programs documented elevated particulate matter and combustion-related pollutants during portions of the incident, supporting conclusions regarding off-site transport of smoke and combustion products. Integration of measured monitoring data with atmospheric modeling substantially strengthened the environmental forensic reconstruction by providing independent verification of predicted transport patterns.
Evaluation of resident observations further supported interpretation of modeled plume behavior. Numerous individuals described dense smoke, visible ash deposition, persistent burning plastic odors, soot accumulation on vehicles and buildings, and acute respiratory and sensory irritation during and immediately following the fire. Reported observations of smoke movement, particulate deposition, and odor persistence were generally consistent with the spatial and temporal patterns identified through atmospheric modeling.
The investigation also highlighted the importance of particulate matter as both a regulated air pollutant and a transport medium for combustion-derived contaminants. Fine particles remained airborne for extended periods before depositing throughout surrounding neighborhoods, while larger particles contributed more rapidly to localized ash deposition. This distinction illustrates how particle size influences both inhalation exposure and environmental contamination following large combustion events.
Another significant finding involved the importance of combining multiple independent datasets during retrospective environmental investigations. Air dispersion modeling alone provides estimates of contaminant transport, whereas environmental monitoring documents actual pollutant concentrations and community observations provide contextual information regarding environmental conditions experienced during the event. Together, these independent sources of information provide a more comprehensive understanding of historical exposures than any single method considered independently.
More broadly, the investigation demonstrates that large industrial fires produce dynamic atmospheric conditions requiring sophisticated environmental forensic techniques to reconstruct historical emissions accurately. Combining engineering analyses, environmental chemistry, atmospheric science, and exposure assessment allows investigators to evaluate complex incidents in a scientifically rigorous manner while accounting for uncertainties inherent in emergency response situations.
Conclusions
This investigation demonstrates how environmental forensic science can be applied to reconstruct community exposure following a large industrial fire through integration of engineering analyses, atmospheric dispersion modeling, environmental monitoring, regulatory information, and scientific literature. By combining multiple independent technical disciplines, investigators developed a scientifically defensible reconstruction of contaminant transport and environmental conditions throughout the incident.
The project also highlights the importance of evaluating combustion-generated particulate matter within the broader context of atmospheric transport, deposition, combustion chemistry, and exposure science. Fine particulate matter not only contributes directly to inhalation exposure but also serves as an important transport mechanism for combustion-derived contaminants, emphasizing the need for comprehensive evaluation following large industrial fire events.
Finally, this investigation illustrates the value of multidisciplinary environmental forensic investigations for evaluating complex environmental incidents. Integrating air dispersion modeling, environmental chemistry, environmental monitoring, geographic information systems, exposure science, and historical reconstruction provides a technically robust framework for understanding contaminant migration, evaluating community exposures, and supporting scientifically defensible environmental conclusions.
This investigation was conducted under the direction of Dr. Paul Rosenfeld, an environmental scientist and President of RoseyFields LLC with more than 30 years of experience in environmental consulting, environmental forensics, and exposure assessment. Dr. Rosenfeld specializes in evaluating complex environmental contamination involving industrial fires, hazardous waste facilities, air emissions, contaminant fate and transport, atmospheric dispersion modeling, risk assessment, and historical exposure reconstruction.
Through RoseyFields LLC, Dr. Rosenfeld provides environmental forensic investigations, expert witness services, regulatory evaluations, and technical consulting for complex environmental matters throughout the United States. His multidisciplinary approach integrates engineering, environmental chemistry, toxicology, atmospheric science, and environmental modeling to develop scientifically defensible conclusions regarding contaminant sources, migration pathways, and potential human and ecological exposures.
References
Agency for Toxic Substances and Disease Registry. (2022). Toxicological profile for particulate matter. U.S. Department of Health and Human Services.
Jenkins, B. M., Jones, A. D., Turn, S. Q., & Williams, R. B. (1996). Emission factors for polycyclic aromatic hydrocarbons from biomass burning. Environmental Science & Technology, 30(8), 2462–2469.
National Research Council. (2011). Guide for air quality and fire emissions assessment. National Academies Press.
U.S. Environmental Protection Agency. (2020). AP-42: Compilation of Air Pollutant Emission Factors.
U.S. Environmental Protection Agency. (2023). AERMOD implementation guide.
U.S. Environmental Protection Agency. (2024). Integrated Science Assessment (ISA) for Particulate Matter.
World Health Organization. (2021). WHO global air quality guidelines: Particulate matter (PM₂.₅ and PM₁₀), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide.