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Compliance with air quality regulations increasingly requires performing risk assessments to estimate potential human health consequences from exposure to air pollutants. EES staff has assisted clients with air toxics risk assessments in the context of New Source Review permitting, state and local air toxics regulations, like the California Air Toxics "Hot Spots" and Information Act (AB2588) and Safe Drinking Water and Toxics Enforcement Act (Proposition 65) and Superfund and RCRA projects.
In addition, Title III of the 1990 Clean Air Act Amendments introduced a new requirement to evaluate the "residual risk" associated with hazardous air pollutant emissions after implementation of maximum achievable control technology (MACT). Typically, the air toxics health risk assessment for a given activity considers exposure of neighboring populations to potentially hazardous compounds by way of multiple environmental pathways (e.g., inhalation, dermal absorption, ingestion). These analyses are designed to determine the pathways responsible for the largest exposures at sensitive receptor locations and, if necessary, to identify viable mitigation measures to reduce health risks to acceptable levels. Representative examples of EES's experience in this technical area are listed to the right.
Air Toxics Health Risk Assessments
ARCO Products Company EES staff helped to prepare air toxics health risk assessments for six ARCO facilities as required by the California Air Toxics "Hot Spots" Information and Assessment Act of 1987. These facilities included an offshore oil and gas platform (Holly) and associated support boats, three onshore production leases (Dos Pueblos, Ellwood Beach, Ojai), an oil and gas processing plant (Ellwood), and a bulk gasoline terminal (San Diego). For each of these assessments, EES staff prepared site specific emissions and meteorological data sets, performed dispersion modeling, and applied a risk quantification model to estimate total community health risks associated with toxic emissions from the subject facilities. Detailed reports documenting the input data, assumptions, analytical methods, and results were prepared for each health risk assessment.
Air Toxics Health Risk Assessments
National Refractories and Minerals Corporation EES staff has provided full service air toxics consulting support for AB 2588 compliance at NRM's two facilities in Monterey County. These are: a dolomite quarry with crushing and calcining operations at Natividad; and magnesia and refractory brick production at Moss Landing. EES staff has prepared air toxics emissions inventory plans and air toxics emissions inventory reports for both facilities and obtained approvals for these documents from the Monterey Bay Unified Air Pollution Control District (MBUAPCD). Extensive source testing to quantify air toxics emissions from NRM sources was required by MBUAPCD. EES staff assisted NRM in devising a test program that made use of pooled data, so that only a fraction of the many individual sources were tested. Additionally, EES staff prepared the required air toxics health risk assessments (ATHRAs) for the Natividad and Moss Landing facilities. Protocols consistent with MBUAPCD guidelines for AB 2588 ATHRAs were presented to the district and subsequently approved. A key component of this effort was the identification and location of sensitive receptors (i.e., hospitals, schools, child and adult day care centers, elderly residential areas, and group homes) within a 5 km radius of the facility. Subsequently, the cancer and non cancer health risk was determined for AB 2588 substances emitted by each facility. The concentration and corresponding health risk of emitted substances at 820 receptors located adjacent to the Moss Landing facility property boundary was of particular importance. This condition was based on the fact (1) that sensitive receptors existed and (2) that an adjacent industrial firm was known to emit identical substances. As a result of this health risk assessment, it was determined that sensitive receptors were not exposed to toxic chemicals in concentrations that warranted risk reduction or pollutant source emission control actions.
Old Vehicle Cleanup Partnership
Bureau of Automotive Repair EES staff developed and managed the implementation of the Old Vehicle Cleanup Partnership Program under a contract with the Santa Barbara County Air Pollution Control District (APCD). The goal of the program was to reduce air pollutant emissions caused by high polluting vehicles in the county. EES staff developed a project implementation plan, monitored project cash flow, prepared project management plan, and participated in negotiating contract terms and conditions to reduce risk and increase profitability. In addition, EES staff involved in facility site acquisition; construction management; and preparation of progress reports detailing the overall project performance, budget, and schedule status. EES staff also coordinated public participation, developing program pamphlets, and conducting training workshops for participating businesses. Under this program vehicles were inspected, tested, and screened for participation in the program.
EIR and Health Risk Assessment
Hazardous Waste Disposal Facility EES engineers helped the County of Imperial to prepare a comprehensive environmental impact report (EIR) for a proposed expansion of an existing waste disposal facility near Westmorland, California. The existing facility consists of landfills for geothermal and other nonhazardous wastes; the proposed project would entail the addition of new facilities for the treatment and disposal of both hazardous and nonhazardous wastes. Originally, a health risk assessment was conducted by another consulting firm under contract to the county and incorporated into the EIR prepared by EES. Because of serious problems with the air toxics element of the health risk assessment that were identified by the reviewing agencies (CARB, DOHS, and Imperial County Department of Health Services), EES staff was requested to re do the ATHRA following the CAPCOA guidelines for AB 2588. The EES staff analysis was accepted without further revisions by the reviewing agencies and the EIR was subsequently certified. A variety of air toxics sources were addressed for the expanded waste disposal facility: (1) fugitive dust generated by the handling of dry materials in the waste stabilization process units and landfill operations; (2) fugitive organic vapors collected from liquid waste storage and processing facilities; (3) combustion or organic vapors in a new steam generator; and (4) potential accidental releases from transportation and process upset conditions. Owing to the diversity of the types of wastes that will be received at the facility, a wide range of specific organic and inorganic toxic contaminants were addressed.
Air Toxics Health Risk Assessment
for a Major West Coast Shipyard National Steel and Shipbuilding Company EES engineers provided comprehensive air toxics consulting services pursuant to California AB2588, including preparation of an air toxics emissions inventory plan, air toxics emissions inventory report and air toxics health risk assessment for this major San Diego shipbuilding and ship repair facility. Project activities included extensive researching of the technical literature to determine the most realistic available emissions factors for relevant facility processes, in particular factors for lead, hexavalent chromium and nickel from welding operations and oil combustion. The exposure of nearby residents to these emissions was evaluated by means of dispersion modeling, as were potential health risks, using approved risk assessment software. EES staff also assisted in developing analyses for review by the California Attorney General pursuant to Proposition 65 requirements for the facility.
Health Risk Assessment
Vulcan Materials, Calmat Division EES staff managed the preparation of a Health Risk Assessment (HRA) conducted for an aggregate handling facility addressing the requirements of the State of California, Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65). Responsibilities involved close coordination with the client's legal team to establish best technical and legal strategy, emissions quantification, risk analysis, and environmental impact from the aggregate operations. |
Overview
Air Toxics Health Risk Assessments EIR and Health Risk Assessment Air Toxics Health Risk Assessment for a Major Health Risk Assessment |