RoseyFields conducted a comprehensive environmental evaluation and cancer risk assessment focusing on toxic air emissions from a large-scale chemical manufacturing plant. The primary chemical of concern evaluated was ethylene oxide (EtO), a colorless gas and known human carcinogen utilized by the facility to produce other chemicals and consumer products. Because the facility self-reported massive quantities of emissions over several decades, and experienced additional unquantified releases due to fugitive leaks and operational mishaps, our team was tasked with quantifying the historical emissions profile and assessing the resulting long-term inhalation exposure pathway for the surrounding residential community.
To accurately characterize the environmental impact of these prolonged releases, our team reconstructed historical emission rates to account for both routine continuous operations and fugitive leaks. We performed advanced air dispersion modeling using the EPA-preferred AERMOD system to simulate the atmospheric transport and dispersion of these emissions. This rigorous technical analysis integrated localized surface and profile meteorological data, terrain elevations, and facility-specific point source parameters to accurately model the ambient air concentrations of the contaminant over a multi-decade period.
Utilizing the air dispersion model outputs, RoseyFields identified and characterized the potential exposure class by establishing multi-scale spatial receptor grids radiating outward from the facility. This methodology allowed us to capture both localized concentration peaks and broader community dispersion patterns caused by the facility’s stack emissions and fugitive leaks. We evaluated long-term residential inhalation exposure by calculating the excess lifetime cancer risk for community members situated within the modeled plume, comparing these ambient concentrations against established federal screening levels to assess the overall hazard to public health.
