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Till J.E.,Risk Assessment Corporation | Grogan H.A.,Cascade Scientific Inc. | Mohler H.J.,Bridger Scientific Inc. | Rocco J.R.,Sage Risk Solutions LLC | And 2 more authors.
Health Physics | Year: 2012

This paper describes a methodology called Risk Analysis, Communication, Evaluation, and Reduction (RACER©) that converts environmental data directly to human health risk to enhance decision making and communication. The methodology was developed and implemented following the Cerro Grande fire in New Mexico that burned approximately 7,500 acres of Los Alamos National Laboratory in May 2000. The absence of a coordinated and comprehensive approach to managing and understanding environmental data was a major weakness in the responding agencies' ability to make and communicate decisions. RACER consists of three basic elements: managing information, converting information to knowledge, and communicating knowledge to decision makers and stakeholders. Data are maintained in a web-accessible database that accepts data as they are validated and uploaded. The user can select data for evaluation and convert them to knowledge using human health risk as a benchmark for ranking radionuclides, chemicals, pathways, or other criteria needed to make decisions. Knowledge about risk is communicated using graphic and tabular formats. The process is transparent, flexible, and rapid, which enhances credibility and trust among decision makers and stakeholders. The fundamental principles used in RACER can be applied anywhere radionuclides or chemicals are present in the environment. Copyright © 2012 Health Physics Society. Source

Till J.E.,Risk Assessment Corporation | Aanenson J.W.,Freeman Inc. | Grogan H.A.,Cascade Scientific Inc. | Mohler H.J.,Bridger Scientific Inc. | Voilleque P.G.,MJP Risk Assessment Inc.
Radiation Research | Year: 2014

Methods were developed to calculate individual estimates of exposure and dose with associated uncertainties for a sub-cohort (1,857) of 115,329 military veterans who participated in at least one of seven series of atmospheric nuclear weapons tests or the TRINITY shot carried out by the United States. The tests were conducted at the Pacific Proving Grounds and the Nevada Test Site. Dose estimates to specific organs will be used in an epidemiological study to investigate leukemia and male breast cancer. Previous doses had been estimated for the purpose of compensation and were generally high-sided to favor the veteran's claim for compensation in accordance with public law. Recent efforts by the U.S. Department of Defense (DOD) to digitize the historical records supporting the veterans' compensation assessments make it possible to calculate doses and associated uncertainties. Our approach builds upon available film badge dosimetry and other measurement data recorded at the time of the tests and incorporates detailed scenarios of exposure for each veteran based on personal, unit, and other available historical records. Film badge results were available for approximately 25% of the individuals, and these results assisted greatly in reconstructing doses to unbadged persons and in developing distributions of dose among military units. This article presents the methodology developed to estimate doses for selected cancer cases and a 1% random sample of the total cohort of veterans under study. © 2014 by Radiation Research Society. Source

This article examines the question, "Is risk assessment fuzzy, or is it a quantitative science?" In the context of this paper, risk assessment is defined as the estimation of health risk to people from exposure to radioactive materials and chemicals when they are released to the environment by a source. Today we employ risk assessment to investigate past, present, and future exposures, and the outcomes of the analysis are used for determining compliance with regulations, emergency response, facility design, and health impacts to populations from historical exposures (dose reconstruction). Risk assessment has become an essential component of government policy and decision-making, and it is clear it will be used increasingly in the future. It has undergone a dramatic evolution since the early 1970s both as a scientific methodology and also in how it is used. The key to understanding risk assessment is to explain the basic components and unique disciplines that meld it together. Each element requires skills in fundamental sciences such as engineering, physics, mathematics, and physiology in order to produce information required for the next step. As each step is developed, a clear interdependence emerges, resulting in a science that is quantitative and reliable and provides a tool for many purposes. In the end, however, it is how we communicate the results that becomes the most important component. © 2014 Health Physics Society. Source

Mohler H.J.,Bridger Scientific Inc. | Grogan H.A.,Cascade Scientific Inc. | Rocco J.R.,Sage Risk Solutions LLC | Kiefer R.F.,1217 Bandana Boulevard North | Till J.E.,Risk Assessment Corporation
Health Physics | Year: 2012

To facilitate access to and use of environmental measurement data, Risk Assessment Corporation has developed a data management system as part of its Risk Analysis, Communication, Evaluation, and Reduction process. The concepts of data consistency are not new, but many data management applications are developed around managing the entire data life cycle, rather than on using the data to reach meaningful conclusions. The RACER process is specifically focused on the efficient use of available data to promote sound decision making. The RACER data management system provides a means of understanding trends in data, comparing data to frequently referenced comparison values, and organizing environmental measurement data for use by other components of the RACER process that evaluate human health impacts. Data transfers to the system can be automated to occur frequently for facilities collecting large volumes of data to achieve a dynamic point of access to measurement data that reflects the most recently available information. Because the RACER process is designed around the most common uses of data, its utility spans a broad range of potential applications, from routine monitoring and reporting to emergency response decision making based on potential human health impacts. Because it is portable and flexible, the elements of the system can be used in any situation where there is a need to efficiently access and interpret environmental measurement data. Its output and functions are equally relevant for small datasets with hundreds of measurements or large and complex datasets with millions of measurements. Copyright © by the Health Physics Society. Source

Till J.E.,Risk Assessment Corporation | Rood A.S.,K and W Inc. | Garzon C.D.,U.S. Department of Energy | Lagdon Jr. R.H.,U.S. Department of Energy
Health Physics | Year: 2014

The suitability of a new facility in terms of potential impacts from routine and accidental releases is typically evaluated using conservative models and assumptions to assure dose standards are not exceeded. However, overly conservative dose estimates that exceed target doses can result in unnecessary and costly facility design changes. This paper examines one such case involving the U.S. Department of Energy's pretreatment facility of the Waste Treatment and Immobilization Plant (WTP). The MELCOR Accident Consequence Code System Version 2 (MACCS2) was run using conservative parameter values in prescribed guidance to demonstrate that the dose from a postulated airborne release would not exceed the guideline dose of 0.25 Sv. External review of default model parameters identified the deposition velocity of 1.0 cm s-as being non-conservative. The deposition velocity calculated using resistance models was in the range of 0.1 to 0.3 cm s-. A value of 0.1 cm s- would result in the dose guideline being exceeded. To test the overall conservatism of the MACCS2 transport model, the 95th percentile hourly average dispersion factor based on one year of meteorological data was compared to dispersion factors generated from two state-of-the-art Lagrangian puff models. The 95th percentile dispersion factor from MACCS2 was a factor of 3 to 6 higher compared to those of the Lagrangian puff models at a distance of 9.3 km and a deposition velocity of 0.1 cm s-. Thus, the inherent conservatism in MACCS2 more than compensated for the high deposition velocity used in the assessment. Applications of models like MACCS2 with a conservative set of parameters are essentially screening calculations, and failure to meet dose criteria should not trigger facility design changes but prompt a more in-depth analysis using probabilistic methods with a defined margin of safety in the target dose. A sample application of the probabilistic approach is provided. Copyright © 2014 Health Physics Society. Source

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