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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Organochlorine pesticides and risk of papillary thyroid cancer in U.S. military personnel: a nested case-control study

Background: The effects of organochlorine pesticide (OCP) exposure on the development of human papillary thyroid cancer (PTC) are not well understood. A nested case-control study was conducted with data from the U.S. Department of Defense Serum Repository (DoDSR) cohort between 2000 and 2013 to assess associations of individual OCPs serum concentrations with PTC risk. Methods: This study included 742 histologically confirmed PTC cases (341 females, 401 males) and 742 individually-matched controls with pre-diagnostic serum samples selected from the DoDSR. Associations between categories of lipid-corrected serum concentrations of seven OCPs and PTC risk were evaluated for classical PTC and follicular PTC using conditional logistic regression, adjusted for body mass index category and military branch to compute odds ratios (OR) and 95% confidence intervals (CIs). Effect modification by sex, birth cohort, and race was examined. Results: There was no evidence of associations between most of the OCPs and PTC, overall or stratified by histological subtype. Overall, there was no evidence of an association between hexachlorobenzene (HCB) and PTC, but stratified by histological subtype HCB was associated with significantly increased risk of classical PTC (third tertile above the limit of detection (LOD) vs. <LOD, OR = 1.61, 95% CI, 1.09, 2.38; p for trend = 0.05) and significantly decreased risk of follicular variant PTC (third tertile above the limit of detection (LOD) vs. <LOD, OR = 0.38, 95% CI, 0.16, 0.91; p for trend = 0.04). Further stratified by sex, risk of classical PTC was higher for females (third tertile above LOD vs. <LOD, OR = 2.23, 95% CI: 1.23, 4.06; p-trend = 0.02) than for males (OR = 1.22, 95%CI: 0.72–2.08; p-trend = 0.56), though the test for interaction by sex was not statistically significant (p-interaction = 0.30). Similarly, β-hexachlorocyclohexane (β-HCCH) was associated with a higher risk for classical PTC for women with concentrations ≥LOD versus <LOD (OR = 1.76, 95% CI: 1.07, 2.89), while the effects were null for men. There were no consistent trends when stratified by race or birth year. Conclusions: The U.S. Environmental Protection Agency has classified HCB and other OCPs we studied here as probable human carcinogens. Our findings of increased risks for classical PTC associated with increased concentrations of HCB and β-HCCH, which were stronger among females, should be replicated in future studies of other populations.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

CATMoS: Collaborative Acute Toxicity Modeling Suite

Background: Humans are exposed to tens of thousands of chemical substances that need to be assessed for their potential toxicity. Acute systemic toxicity testing serves as the basis for regulatory hazard classification, labeling, and risk management. However, it is cost- and time-prohibitive to evaluate all new and existing chemicals using traditional rodent acute toxicity tests. In silico models built using existing data facilitate rapid acute toxicity predictions without using animals. Objectives: The U.S. Interagency Coordinating Committee on the Validation of Alternative Methods Acute Toxicity Workgroup organized an international collaboration to develop in silico models for predicting acute oral toxicity based on five different endpoints: LD50 value, U.S. Environmental Protection Agency hazard categories, Globally Harmonized System for Classification and Labelling hazard categories, very toxic chemicals (LD50 =50 mg/kg), and non-toxic chemicals (LD50 >2000 mg/kg). Methods: An acute oral toxicity data inventory for 11,992 chemicals was compiled, split into training and evaluation sets, and made available to 35 participating international research groups that submitted a total of 139 predictive models. Predictions that fell within the applicability domains of the submitted models were evaluated using external validation sets. These were then combined into consensus models to leverage strengths of individual approaches. Results: The resulting consensus predictions, which leverage the collective strengths of each individual model, form the Collaborative Acute Toxicity Modeling Suite (CATMoS). CATMoS demonstrated high performance in terms of accuracy and robustness when compared to in vivo results. Discussion: CATMoS is being evaluated by regulatory agencies for its utility and applicability as a potential replacement for in vivo rat acute oral toxicity studies. CATMoS predictions for over 800,000 chemicals have been made available via the NTP’s Integrated Chemical Environment. The models are also implemented in a free, standalone open-source tool, OPERA, which allows predictions of new and untested chemicals to be made.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2025

bmdrc: Python package for quantifying phenotypes from chemical exposures with benchmark dose modeling

Though chemical exposures are known to potentially have negative impacts on health, including contributing to chronic diseases such as cancer, the quantitative contribution of risk is not fully understood for every chemical. A commonly used approach to quantify levels of risk is to measure the proportion of organisms (such as a total number of zebrafish on a plate or mice in a cage) with abnormal behavioral responses or morphology at increasing concentrations of chemical exposure. A particular challenge with processing the proportional data from these assays is the appropriate estimation of chemical concentration levels that result in malformations or acute toxicity, as these values typically vary between experimental measurements. The recommended approach by the Environmental Protection Agency (EPA) is to fit benchmark dose curves with specific filters and model fitting steps, which are crucial to properly processing the proportional data. Several tools exist for the fitting of benchmark dose response curves, but none are standalone Python libraries built to process both morphological and behavioral data as proportions with all the EPA recommended filters, filter parameters, models, and model parameters. Thus, here we present the benchmark dose response curve (bmdrc) Python library, which was built to closely follow these EPA guidelines with helpful visualizations of filters and fitted model curves, and reports for reproducibility purposes. bmdrc is open-source and has demonstrated utility as a support package to an existing web portal for information on chemicals (https://srp.pnnl.gov). Our package will support any toxicology analysis where the response is a proportional value at increasing levels of a concentration of a chemical or chemical mixture.

Superfund↗
DOE OSTI2018

Uncertainty quantification in ToxCast high throughput screening

High throughput screening (HTS) projects like the U.S. Environmental Protection Agency’s ToxCast program are required to address the large and rapidly increasing number of chemicals for which we have little to no toxicity measurements. Concentration-response parameters such as potency and efficacy are extracted from HTS data using nonlinear regression, and models and analyses built from these parameters are used to predict in vivo and in vitro toxicity of thousands of chemicals. How these predictions are impacted by uncertainties that stem from parameter estimation and propagated through the models and analyses has not been well explored. While data size and complexity makes uncertainty quantification computationally expensive for HTS datasets, continued advancements in computational resources have allowed these computational challenges to be met. This study uses nonparametric bootstrap resampling to calculate uncertainties in concentration-response parameters from a variety of HTS assays. Using the ToxCast estrogen receptor model for bioactivity as a case study, we highlight how these uncertainties can be propagated through models to quantify the uncertainty in model outputs. Uncertainty quantification in model outputs is used to identify potential false positives and false negatives and to determine the distribution of model values around semi-arbitrary activity cutoffs, increasing confidence in model predictions. At the individual chemical-assay level, curves with high variability are flagged for manual inspection or retesting, focusing subject-matter-expert time on results that need further input. This work improves the confidence of predictions made using HTS data, increasing the ability to use this data in risk assessment.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Concrete Testing Case for Closure of Handford’s 241-C Underground Storage Tanks

Sixty percent of the nation's highly toxic and radioactive mixed wastes are stored at Hanford in 177 deteriorating underground storage tanks. To close or remove these storage tanks from service and place them in a condition that is protective of human health and the environment, the tanks must be physically stabilized to prevent subsidence once wastes have been retrieved. Remaining residual liquid waste in the tanks that cannot be removed must be solidified and the solid wastes encapsulated to meet the Nuclear Regulatory Commission, Department of Energy, Environmental Protection Agency, and the State of Washington requirements. The Department of Energy has developed cementitious flowable concretes to restrict access and provide chemical stabilization for radionuclides. Formulation, laboratory, and field testing for application at Hanford began with flowable, self-leveling structural and non-structural fills. A slump flow equal to or greater than 610 mm, 0% bleed water, and 0.1% (by volume) shrinkage measurements were key parameters guiding reformulation efforts that resulted in highly flowable, self-consolidating concretes that met Hanford 241-C Tank closure short- and long-term regulatory and engineering performance requirements.

formula development↗
DOE OSTI2017

Fuel economy and emissions testing of an RCCI series hybrid vehicle

In the current work, a series hybrid vehicle has been constructed that utilises a dual-fuel, reactivity controlled compression ignition (RCCI) engine. Full vehicle testing was conducted on chassis dynamometers over the US Environmental Protection Agency Federal Test Procedure, Highway Fuel Economy Test and US06 using RCCI combustion with commercially available gasoline and ultra-low sulphur diesel. Fuel economy and emissions data were recorded over the specified test cycles. Testing revealed that engine-out emissions were similar to steady-state dynamometer engine testing. However, tailpipe-out emissions saw a reduction of HC and CO during the HWFET of 98.5%. Fuel economy was lower than expected due to the higher drivetrain losses of the series hybrid drivetrain. Finally, simulated changes to the drivetrain showed that it may be possible to increase fuel economy significantly, while meeting EPA emissions standards.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2024

Durability testing of actual Hanford waste glasses and their non-radioactive simulant glasses

The low-activity waste (LAW) fraction of Hanford tank waste will be converted to glass at the Waste Treatment and Immobilization Plant (WTP) and disposed on the Hanford site. The chemical durability of LAW glasses has been researched for decades to satisfy contract requirements. Most LAW glass durability data has been generated on non-radioactive simulant glasses fabricated via crucible melts. These non-radioactive glasses were chosen due to safety and cost reasons with confidence that radioactive waste glasses would exhibit similar behavior. To reduce the risk of significant differences in laboratory test response data between WTP melter waste glass and simulant glass, Product Consistency Tests (PCT, i.e., ASTM C1285-21) and Environmental Protection Agency (EPA) 1313 durability tests were performed on actual and simulant LAW glasses fabricated using laboratory-scaled melters. Actual and simulant glass durability test results are presented and statistically compared. Finally, differences in test responses were found to be within experimental uncertainty.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Improving cellulose attribution by selectively removing yeast glucans from grain fermentation intermediates

Abstract This article presents an industry-relevant method for quantifying cellulose in mixed substrate samples. We built upon the cellulosic glucan measurement proposed by Sluiter et al. (2021) to investigate significant cellulose loss under cold caustic conditions, which has hindered the establishment of an industrially relevant method. To overcome this issue, we used dimethyl sulfoxide (DMSO) as an alternative solvent, which avoids mercerization reactions (Budtova and Navard 2015) but may leave some resistant starch in the sample. Treatment via an enzyme mixture removed starch and conformed to US Environmental Protection Agency (EPA) guidance on cellulose measurement by establishing quantitative de-starching via nuclear magnetic resonance (EPA 2022). The selective removal of yeast beta-glucan was accomplished using a commercially available Zymolyase. Our results demonstrated excellent reproducibility, with coefficients of variance of 7.14% or less, when measuring cellulose in low cellulose content samples. The method was tested on relevant lab and plant samples, showing an average 0.9% ethanol derived from the conversion of cellulose when cellulase was added to the process and zero response when no cellulase was added. These findings indicate that a cellulose method using DMSO and pullulanase provides a complete and accurate view of cellulose content, composition, and conversion in industrial fermentation processes.

Sluiter, Justin [National Renewable Energy Laborat↗
DOE OSTI2012

Argonne National Laboratory Site Environmental Report for Calendar Year 2011

This report discusses the status and the accomplishments of the environmental protection program at Argonne National Laboratory for calendar year 2011. The status of Argonne environmental protection activities with respect to compliance with the various laws and regulations is discussed, along with environmental management, sustainability efforts, environmental corrective actions, and habitat restoration. To evaluate the effects of Argonne operations on the environment, samples of environmental media collected on the site, at the site boundary, and off the Argonne site were analyzed and compared with applicable guidelines and standards. A variety of radionuclides were measured in air, surface water, on-site groundwater, and bottom sediment samples. In addition, chemical constituents in surface water, groundwater, and Argonne effluent water were analyzed. External penetrating radiation doses were measured, and the potential for radiation exposure to off-site population groups was estimated. Results are interpreted in terms of the origin of the radioactive and chemical substances (i.e., natural, Argonne, and other) and are compared with applicable standards intended to protect human health and the environment. A U.S. Department of Energy (DOE) dose calculation methodology, based on International Commission on Radiological Protection (ICRP) recommendations and the U.S. Environmental Protection Agency’s (EPA) CAP-88 Version 3 computer code, was used in preparing this report.

Davis, Theresa M.↗
DOE OSTI2012

D NA R ecovery from A erosol F iltration and T ransport (DRAFT)

According to an article in Science Matters, the newsletter of the Environmental Protection Agency, the average adult breathes in over 3,000 gallons of air every day. For this reason, having good air quality is extremely important. Many allergen particles are present in the atmosphere that interfere with this quality. When HVAC systems are installed to direct airflow through buildings, many of these particles are transferred indoors. To ensure air quality within buildings, tracking the flow patterns of these particles as the air is dispersed through heating and cooling systems is vital. One method to monitor this is through the creation of aerosolized particles with a DNA barcode (about 100 base pairs) that can be released and recaptured.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Quantifying the Effects of Idle-Stop Systems on Fuel Economy in Light-Duty Passenger Vehicles

Vehicles equipped with idle-stop (IS) systems are capable of engine shut down when the vehicle is stopped and rapid engine re-start for the vehicle launch. This capability reduces fuel consumption and emissions during periods when the engine is not being utilized to provide propulsion or to power accessories. IS systems are a low-cost and fast-growing technology in the industry-wide pursuit of increased vehicle efficiency, possibly becoming standard features in European vehicles in the near future. In contrast, currently there are only three non-hybrid vehicle models for sale in North America with IS systems and these models are distinctly low-volume models. As part of the United States Department of Energy’s Advanced Vehicle Testing Activity, ECOtality North America has tested the real-world effect of IS systems on fuel consumption in three vehicle models imported from Europe. These vehicles were chosen to represent three types of systems: (1) spark ignition with 12-V belt alternator starter; (2) compression ignition with 12-V belt alternator starter; and (3) direct-injection spark ignition, with 12-V belt alternator starter/combustion restart. The vehicles have undergone both dynamometer and on-road testing; the test results show somewhat conflicting data. The laboratory data and the portion of the on-road data in which driving is conducted on a prescribed route with trained drivers produced significant fuel economy improvement. However, the fleet data do not corroborate improvement, even though the data show significant engine-off time. It is possible that the effects of the varying driving styles and routes in the fleet testing overshadowed the fuel economy improvements. More testing with the same driver over routes that are similar with the IS system-enabled and disabled is recommended. There is anecdotal evidence that current Environmental Protection Agency fuel economy test procedures do not capture the fuel economy gains that IS systems produce in real-world driving. The program test results provide information on the veracity of these claims.

25 ENERGY STORAGE↗
DOE OSTI2013

Statistical Analysis of Tank 5 Floor Sample Results (U)

Sampling has been completed for the characterization of the residual material on the floor of Tank 5 in the F-Area Tank Farm at the Savannah River Site (SRS), near Aiken, SC. The sampling was performed by Savannah River Remediation (SRR) LLC using a stratified random sampling plan with volume-proportional compositing. The plan consisted of partitioning the residual material on the floor of Tank 5 into three non-overlapping strata: two strata enclosed accumulations, and a third stratum consisted of a thin layer of material outside the regions of the two accumulations. Each of three composite samples was constructed from five primary sample locations of residual material on the floor of Tank 5. Three of the primary samples were obtained from the stratum containing the thin layer of material, and one primary sample was obtained from each of the two strata containing an accumulation. This report documents the statistical analyses of the analytical results for the composite samples. The objective of the analysis is to determine the mean concentrations and upper 95% confidence (UCL95) bounds for the mean concentrations for a set of analytes in the tank residuals. The statistical procedures employed in the analyses were consistent with the Environmental Protection Agency (EPA) technical guidance by Singh and others [2010]. Savannah River National Laboratory (SRNL) measured the sample bulk density, nonvolatile beta, gross alpha, and the radionuclide1, elemental, and chemical concentrations three times for each of the composite samples. The analyte concentration data were partitioned into three separate groups for further analysis: analytes with every measurement above their minimum detectable concentrations (MDCs), analytes with no measurements above their MDCs, and analytes with a mixture of some measurement results above and below their MDCs. The means, standard deviations, and UCL95s were computed for the analytes in the two groups that had at least some measurements above their MDCs. The identification of distributions and the selection of UCL95 procedures generally followed the protocol in Singh, Armbya, and Singh [2010]. When all of an analyte's measurements lie below their MDCs, only a summary of the MDCs can be provided. The measurement results reported by SRNL are listed, and the results of this analysis are reported. The data were generally found to follow a normal distribution, and to be homogenous across composite samples.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

RCRA Permit for a Hazardous Waste Management Facility Permit Number NEV HW0101 Annual Summary/Waste Minimization Report Calendar Year 2012, Nevada National Security Site, Nevada

This report summarizes the U.S. Environmental Protection Agency (EPA) identification number of each generator from which the Permittee received a waste stream, a description and quantity of each waste stream in tons and cubic feet received at the facility, the method of treatment, storage, and/or disposal for each waste stream, a description of the waste minimization efforts undertaken, a description of the changes in volume and toxicity of waste actually received, any unusual occurrences, and the results of tank integrity assessments. This Annual Summary/Waste Minimization Report is prepared in accordance with Section 2.13.3 of Permit Number NEV HW0101, issued 10/17/10.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Summary of Fast Pyrolysis and Upgrading GHG Analyses

The Energy Independence and Security Act (EISA) of 2007 established new renewable fuel categories and eligibility requirements (EPA 2010). A significant aspect of the National Renewable Fuel Standard 2 (RFS2) program is the requirement that the life cycle greenhouse gas (GHG) emissions of a qualifying renewable fuel be less than the life cycle GHG emissions of the 2005 baseline average gasoline or diesel fuel that it replaces. Four levels of reduction are required for the four renewable fuel standards. Table 1 lists these life cycle performance improvement thresholds. Table 1. Life Cycle GHG Thresholds Specified in EISA Fuel Type Percent Reduction from 2005 Baseline Renewable fuel 20% Advanced biofuel 50% Biomass-based diesel 50% Cellulosic biofuel 60% Notably, there is a specialized subset of advanced biofuels that are the cellulosic biofuels. The cellulosic biofuels are incentivized by the Cellulosic Biofuel Producer Tax Credit (26 USC 40) to stimulate market adoption of these fuels. EISA defines a cellulosic biofuel as follows (42 USC 7545(o)(1)(E)): The term “cellulosic biofuel” means renewable fuel derived from any cellulose, hemicellulose, or lignin that is derived from renewable biomass and that has lifecycle greenhouse gas emissions, as determined by the Administrator, that are at least 60 percent less than the baseline lifecycle greenhouse gas emissions. As indicated, the Environmental Protection Agency (EPA) has sole responsibility for conducting the life cycle analysis (LCA) and making the final determination of whether a given fuel qualifies under these biofuel definitions. However, there appears to be a need within the LCA community to discuss and eventually reach consensus on discerning a 50–59 % GHG reduction from a ≥ 60% GHG reduction for policy, market, and technology development. The level of specificity and agreement will require additional development of capabilities and time for the sustainability and analysis community, as illustrated by the rich dialogue and convergence around the energy content and GHG reduction of cellulosic ethanol (an example of these discussions can be found in Wang 2011). GHG analyses of fast pyrolysis technology routes are being developed and will require significant work to reach the levels of development and maturity of cellulosic ethanol models. This summary provides some of the first fast pyrolysis analyses and clarifies some of the reasons for differing results in an effort to begin the convergence on assumptions, discussion of quality of models, and harmonization.

Biofuel↗
DOE OSTI2013

Annual Energy Outlook 2013 With Projections to 2040

The Annual Energy Outlook 2013 (AEO2013), prepared by the U.S. Energy Information Administration (EIA), presents long-term projections of energy supply, demand, and prices through 2040, based on results from EIA’s National Energy Modeling System. The report begins with an “Executive summary” that highlights key aspects of the projections. It is followed by a “Legislation and regulations” section that discusses evolving legislative and regulatory issues, including a summary of recently enacted legislation and regulations, such as: Updated handling of the U.S. Environmental Protection Agency’s (EPA) National Emissions Standards for Hazardous Air Pollutants for industrial boilers and process heaters; New light-duty vehicle (LDV) greenhouse gas (GHG) and corporate average fuel economy (CAFE) standards for model years 2017 to 2025; Reinstatement of the Clean Air Interstate Rule (CAIR) after the court’s announcement of intent to vacate the Cross-State Air Pollution Rule (CSAPR); and Modeling of California’s Assembly Bill 32, the Global Warming Solutions Act (AB 32), which allows for representation of a cap-and-trade program developed as part of California’s GHG reduction goals for 2020. The “Issues in focus” section contains discussions of selected energy topics, including a discussion of the results in two cases that adopt different assumptions about the future course of existing policies, with one case assuming the elimination of sunset provisions in existing policies and the other case assuming the elimination of the sunset provisions and the extension of a selected group of existing public policies—CAFE standards, appliance standards, and production tax credits. Other discussions include: oil price and production trends in AEO2013; U.S. reliance on imported liquids under a range of cases; competition between coal and natural gas in electric power generation; high and low nuclear scenarios through 2040; and the impact of growth in natural gas liquids production. The “Market trends” section summarizes the projections for energy markets. The analysis in AEO2013 focuses primarily on a Reference case, Low and High Economic Growth cases, and Low and High Oil Price cases. Results from a number of other alternative cases also are presented, illustrating uncertainties associated with the Reference case projections for energy demand, supply, and prices. Complete tables for the five primary cases are provided in Appendixes A through C. Major results from many of the alternative cases are provided in Appendix D. Complete tables for all the alternative cases are available on EIA’s website in a table browser at http://www.eia.gov/oiaf/aeo/tablebrowser. AEO2013 projections are based generally on federal, state, and local laws and regulations in effect as of the end of September 2012. The potential impacts of pending or proposed legislation, regulations, and standards (and sections of existing legislation that require implementing regulations or funds that have not been appropriated) are not reflected in the projections. In certain situations, however, where it is clear that a law or regulation will take effect shortly after the Annual Energy Outlook (AEO) is completed, it may be considered in the projection.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2013

Idaho National Laboratory PCB Annual Document Log and Annual Records Report for Calendar Year 2012

The requirements for the reporting of polychlorinated biphenyl (PCB)-related activities are found in 40 Code of Federal Regulations (CFR) 761 Subpart J, "General Records and Reports." The PCB Annual Document Log is a detailed record of the PCB waste handling activities at the facility. The facility must prepare it each year by July 1 and maintain it at the facility for at least 3 years after the facility ceases using or storing PCBs and PCB items. While submittal of the PCB Annual Document Log to the U.S. Environmental Protection Agency (EPA) is not required by regulation, EPA has verbally requested in telephone conversations that this report be submitted to them on an annual basis.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2013

Quantifying VOC Emissions for the Strategic Petroleum Reserve

A very important aspect of the Department of Energy's (DOE's) Strategic Petroleum Reserve (SPR) program is regulatory compliance. One of the regulatory compliance issues deals with limiting the amount of volatile organic compounds (VOCs) that are emitted into the atmosphere from brine wastes when they are discharged to brine holding ponds. The US Environmental Protection Agency (USEPA) has set limits on the amount of VOCs that can be discharged to the atmosphere. Several attempts have been made to quantify the VOC emissions associated with the brine ponds going back to the late 1970 s. There are potential issues associated with each of these quantification efforts. Two efforts were made to quantify VOC emissions by analyzing VOC content of brine samples obtained from wells. Efforts to measure air concentrations were mentioned in historical reports but no data have been located to confirm these assertions. A modeling effort was also performed to quantify the VOC emissions. More recently in 2011- 2013, additional brine sampling has been performed to update the VOC emissions estimate. An analysis of the statistical confidence in these results is presented here. Arguably, there are uncertainties associated with each of these efforts. The analysis herein indicates that the upper confidence limit in VOC emissions based on recent brine sampling is very close to the 0.42 ton/MMB limit used historically on the project. Refining this estimate would require considerable investment in additional sampling, analysis, and monitoring. An analysis of the VOC emissions at each site suggests that additional discharges could be made and stay within current regulatory limits.

Knowlton, Robert G.↗
DOE OSTI2013

Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Isobutanol-blended Gasoline

The Energy Independence and Security Act (EISA) of 2007 is an omnibus energy policy law designed to move the United States toward greater energy security and independence. A key provision of EISA is the Renewable Fuel Standard (RFS), which requires the nation to use 36 billion gallons per year (BGPY) of renewable fuel in vehicles by 2022. Ethanol is the most widely used renewable fuel, and increasing the allowable ethanol content from 10% to 15% is expected to push renewable fuel consumption to as much as 21 BGPY. Therefore, a large portion of the 36 billion gallon requirement can be met by increasing the ethanol content in gasoline to 15%. However, raising the ethanol content to 15%, by itself, will still not fully meet the RSF requirement, and concerns have been raised that this increase in ethanol may not be entirely compatible with current and legacy materials used in standard gasoline fueling systems. In the summer of 2008, the U.S. Department of Energy (DOE) recognized the need to assess the impact of intermediate blends of ethanol on the fueling infrastructure, specifically those systems located at the fueling station. A short time later (March 2009), Growth Energy (a coalition of ethanol producers and supporters) requested a waiver from the U.S. Environmental Protection Agency (EPA) to allow the use of 15% ethanol in gasoline. In 1981 the EPA approved a waiver (known as the OCTAMIX waiver) that allowed other alcohol types (such as methanol) to be blended with gasoline as long as the resulting fuel blend was substantially similar to gasoline. Another requirement is that the fuel oxygen content cannot exceed 3.7 wt %. Currently, this requirement limits ethanol in gasoline to 10 vol %. The corresponding oxygen equivalent for isobutanol is 16 vol %; therefore, isobutanol offers a pathway towards meeting the RFS requirement by allowing greater biofuel usage than can be achieved by ethanol alone. In fact, the United States has already hit the “blend wall” for ethanol, the point at which virtually all gasoline sold is E10 and no remaining market is left for ethanol, meaning that the country cannot substantially increase ethanol usage unless the EPA allows for higher levels of ethanol or until E85 use is expanded significantly. Butamax Advanced Biofuels, LLC has developed proprietary technologies to convert corn into isobutanol. Much of the infrastructure already existing at ethanol plants can be readily converted to produce isobutanol instead. The focus of this investigation was to compare the compatibility of fueling infrastructure materials (such as elastomers, plastics, and metals) to test fuels representing E10 and E15 and their corresponding oxygen equivalents with isobutanol (iBu16 and iBu24). Butamax sponsored a research project at Oak Ridge National Laboratory (ORNL) to perform empirical studies using aggressive fuel formulations representing 16 and 24% isobutanol. The results contained within this report include a solubility analysis for each material type and fuel formulation and empirical results for elastomers, plastics, and metals. Data obtained from the preceding ethanol compatibility studies on these materials are included for additional interpretation and summary.

Kass, Michael D.↗