A review of the U.S. Environmental Protection Agency's Research Program on the prevention and control of hazardous material spills

This paper is a status report on a number of the projects in progress at the Industrial Waste Treatment Research Laboratory of the U.S. Environmental Protection Agency at Edison, New Jersey. The actual causes of numerous hazardous material spills have been documented and analyzed to assign priority to operational areas in which spill prevention and control procedures are urgently needed. Spill alert systems are ready for installation on marginally safe earthen holding pond dikes. Fail-safe systems are being evaluated to reduce spillage from overfilling and from transfer line rupture. The handling of spills in municipalities has been addressed with particular attention to the maintenance and utilization of secondary sewage treatment facilities during spill events.Among the physical and chemical treatment systems that have been or are being produced are trailer-mounted units for processing contaminated water. Also, special devices are being designed for the dispersion and recovery — where necessary — of adsorbents and counteractive chemical reagents for in situ treatment of polluted water bodies. Plastic foams have been developed to dike or confine spills and to plug leaks in ruptured containers. A pickup truck-mounted collection unit, consisting of a battery-powered pump and a self-deploying plastic storage bag, has been constructed and tested.Nearing final testing is a “Sea Curtain”, which extends from the bottom of a stream to the air above. The “Curtain” can be used to isolate a water column that is being contaminated by a soluble, sinking, or floating hazardous material discharged from shore or in stream. Gelling and solidification agents have been shown to be effective in immobilizing spilled hazardous materials. Systems are being built to reprocess treatment agents for reuse and to detoxify whatever agents or recovered materials cannot be salvaged. Field-use packets and other easy-to-deploy items are being developed to trace spills in water and to assess the effectiveness of cleanup. Procedures for enhanced, in-place, biological degradation of spilled hazardous materials are under test.The thrust of the Laboratory's program in these and in related projects is toward the demonstration of practical procedures, hardware, and suitably engineered systems for the prevention and control of spills of hazardous materials.     

Universal gelling agent for the control of hazardous liquid spills

Under contract to the U.S. Environmental Protection Agency, Calspan Corporation developed methods to treat, control and monitor spilled hazardous materials. One of the most successful spill countermeasures applied was a dry, finely-granulated blend which would, within seconds after contact with spilled liquids, begin their transformation into tough, immobile gels which could be easily controlled and removed. This blend is a “universal gelling agent” in the sense that it can immobilize essentially all hazardous liquid spills without foreknowledge of the liquid composition. The blend contains powdered polymeric components optimized separately for interaction with aqueous liquids, chlorinated organics, alcohols, and nonpolar hydrocarbons. It also contains a fumed silica fluidizer, which provides ease of field application and imparts longer term stiffening of all gels formed. The “universal gelling agent” has been demonstrated to be effective on a variety of medium scale (55-gallon drum) spills on both land and water. For special uses, such as organophosphorus pesticide spill control, the blend can be reformulated to include de-toxifying (oxidizing, hydrolytic) ingredients as well.     

A quantitative risk analysis approach to port hydrocarbon logistics

A method is presented that allows quantitative risk analysis to be performed on marine hydrocarbon terminals sited in ports. A significant gap was identified in the technical literature on QRA for the handling of hazardous materials in harbours published prior to this work. The analysis is extended to tanker navigation through port waters and loading and unloading facilities. The steps of the method are discussed, beginning with data collecting. As to accident scenario identification, an approach is proposed that takes into account minor and massive spills due to loading arm failures and tank rupture. Frequency estimation is thoroughly reviewed and a shortcut approach is proposed for frequency calculation. This allows for the two-fold possibility of a tanker colliding/grounding at/near the berth or while navigating to/from the berth. A number of probability data defining the possibility of a cargo spill after an external impact on a tanker are discussed. As to consequence and vulnerability estimates, a scheme is proposed for the use of ratios between the numbers of fatal victims, injured and evacuated people. Finally, an example application is given, based on a pilot study conducted in the Port of Barcelona, where the method was tested.     

A flame-retardant post-synthetically functionalized COF sponge as absorbent for spilled oil recovery

Journal of Materials Science - Frequent oil spills pose severe damages to the marine ecosystems and result in hazardous fires when the spilled oil is ignited. Developing high-performance,...     

Safety risk assessment and management—the ESA approach

The European Space Agency ESA aims at minimizing the safety risks of their space flight projects. Hazard and risk reduction is supported by hazard analysis and probabilistic risk assessment. In hazard analysis hazardous conditions and accident scenarios are identified. Risk assessment is the probabilistic evaluation of accident scenarios and is the basis for risk management. The risk assessment method involves the determination and propagation of event probability. Expert judgement is used in a structured way. In risk management the risk assessment results are used to prioritize and optimize risk reduction efforts and to support risk acceptance evaluations.     

Experimental study of the spill and vaporization of a volatile liquid

Pool and vapor cloud characteristics of an acetone spill issuing from the downstream wall of a flow obstruction oriented perpendicular to a uniform flow were investigated experimentally. Data indicate that the spill event was largely governed by the temperature of the surface in relation to the boiling point of the spilled liquid. The free stream velocity (ranging from 0.75 to 3.0m/s) also impacted the spreading of the spill. Planar laser-induced fluorescence (PLIF) was used to measure acetone vapor concentrations during the transient pool spreading and vaporization in a window 60cm long by 50cm high and located downstream of the 16cm high obstruction. The recirculation region induced by the flow obstruction caused upstream transport of the acetone vapor along the spill surface, after which it was convected vertically along the obstruction wall before being entrained into the flow and convected downstream. The recirculating flow caused regions of vapor within the flammability limits to be localized near the flow obstruction. These regions moved into and out of the measurement plane by large three-dimensional flow structures. The flammable region of the evolved vapor cloud was observed to grow well past the downstream edge of the measurement domain. With decreasing wind speeds, both the mass of acetone vapor within the flammability limits and the total spill event time increased significantly. The data presented herein provides a basis for validating future spill models of hazardous chemical releases, where complex turbulent flow modeling must be coupled with spill spreading and vaporization dynamics.     

Comparison of spectra using a Bayesian approach. An argument using oil spills as an example

The problem of assigning a probability of matching a number of spectra is addressed. The context is in environmental spills when an EPA needs to show that the material from a polluting spill (e.g., oil) is likely to have originated at a particular site (factory, refinery) or from a vehicle (road tanker or ship). Samples are taken from the spill, and candidate sources and are analyzed by spectroscopy (IR, fluorescence) or chromatography (GC or GC/MS). A matching algorithm is applied to pairs of spectra giving a single statistic (R). This can be a point-to-point match giving a correlation coefficient or a Euclidean distance or a derivative of these parameters. The distributions of R for same and different samples are established from existing data. For matching statistics with values in the range {0,1} corresponding to no match (0) to a perfect match (1) a beta distribution can be fitted to most data. The values of R from the match of the spectrum of a spilled oil and of each of a number of suspects are calculated and Bayes' theorem is applied to give a probability of matches between spill sample and each candidate and the probability of no match at all. The method is most effective when simple inspection of the matching parameters does not lead to an obvious conclusion; i.e., there is overlap of the distributions giving rise to dubiety of an assignment. The probability of finding a matching statistic if there were a match to the probability of finding it if there were no match, expressed as a ratio (called the likelihood ratio), is a sensitive and useful parameter to guide the analyst. It is proposed that this approach may be acceptable to a court of law and avoid challenges of apparently subjective opinion of an analyst. Examples of matching the fluorescence and infrared spectra of diesel oils are given.     

Weathering of a subarctic oil spill over 25 years: the Caribou-Poker Creeks Research Watershed experiment

A small experimental oil spill conducted in an open black spruce forest within the Caribou-Poker Creeks Research Watershed (CPCRW), 48 km north of Fairbanks, AK, in the winter of 1976 was designed to examine the effects of crude oil spills in permafrost terrain. No clean-up was attempted, and the site now provides an opportunity to follow the natural weathering of spilled oil under these conditions. In summer 2001, more than 25 years after the spill, we sampled soils from the spill plot and a nearby reference plot to determine how the oil had weathered, and to assess microbial populations and activity. All samples collected from the oiled plot contained substantial amounts of methylene chloride extractable oil, between 4% and 66% by weight. Using 17α(H)21β(H)hopane as a conserved internal marker within the oil, we determined that while some heavily oiled samples were almost unchanged since the spill, others had lost more than 80% of their initial hydrocarbon. Evaporation, biodegradation and photooxidation all seem to have played important roles in this process, but to varying degrees in different samples. Assays of culturable populations of total heterotrophs and crude oil emulsifiers, and mineralization potentials for hexadecane and phenanthrene, indicate that the microbial population in the oiled soils has remained acclimated to degrade hydrocarbons. We conclude that natural weathering processes will eventually lead to the removal of much of the hydrocarbon from these heavily oiled subarctic soils; however, the combination of low rates of nutrient turnover, a short thaw season, and high hydrocarbon concentrations will result in the persistence of oil residue for many more decades. Finding an environmentally appropriate cleanup technology for sites like this remains an important challenge for future research.     

State and national resources for community spill disaster preparedness in the united states

United States local contingency planning is considered from the special perspective of the resources available at the state and federal levels for hazardous materials accidents and emergency spills. The National Response Network for the United States is described in terms of the units and levels of government constituting that capability. Special features of local plans are discussed, and communications with state and federal response agencies are emphasized. State and federal resources for hazardous spill planning and response are described, particularly within the context of the regional and national response teams. The additional benefits of the agressive assistance of commercial and industrial assistance are discussed, and the additional benefits of local spill planning to the community are described. The article lists the regional U.S. Environmental Protection Agency contacts for spill response planning assistance.     

Extensions of the uncertainty quantification of common cause failure rates

Uncertainties in common cause event observation, documentation and interpretation are taken into account by conditional probabilities and generalized impact vector weights that separate single and double events of a specific multiplicity in a single observation. Distributions and moments of common cause failure (CCF) rates of a system are obtained in terms of the weights by using probability generating functions, combining assessment uncertainties and statistical uncertainties. These results are then used to generate effective plant-specific input data to general empirical Bayes estimation methods to combine data from many plants. The posterior output yields CCF probabilities for standby safety system fault tree analysis or probabilistic safety assessments of a target plant.     

Structural damage identification via time domain response and Markov Chain Monte Carlo method

The present work addresses the problem of structural damage identification built on the statistical inversion approach. Here, the damage state of the structure is continuously described by a cohesion parameter, which is spatially discretized by the finite element method. The inverse problem of damage identification is then posed as the determination of the posterior probability densities of the nodal cohesion parameters. The Markov Chain Monte Carlo method, implemented with the Metropolis–Hastings algorithm, is considered in order to approximate the posterior probabilities by drawing samples from the desired joint posterior probability density function. With this approach, prior information on the sought parameters can be used and the uncertainty concerning the known values of the material properties can be quantified in the estimation of the cohesion parameters. The assessment of the proposed approach has been performed by means of numerical simulations on a simply supported Euler–Bernoulli beam. The damage identification and assessment are performed considering time domain response data. Different damage scenarios and noise levels were addressed, demonstrating the feasibility of the proposed approach.     

Time-correlations in the dynamics of hazardous material pipelines incidents

This paper addresses the following question: Are the hazardous materials pipeline incidents non-randomly time distributed? Our analysis suggests that they are correlated, which means that a hazardous materials pipeline incident is not independent from the time elapsed since the previous event. That is, our statistical tests suggest that previous accident counts correlate with future counts. But, if we consider incidents with a large severity index (spills and property damage), the phenomenon is unpredictable, since it approaches a Poissonian process (random, independent and uncorrelated).     

Development of a terrestrial chemical spill management system

Adequately preparing for and responding to terrestrial (land-based) chemical spills are critical to the protection of human health and the environment. To facilitate analysis and support decision-making for such events, the authors have developed an environmental risk management system that characterizes the ability of a spilled chemical to immediately impact human health, groundwater, surface water, and soil resources, and incorporates these four risk areas into an overall measure of terrestrial chemical risk. This system incorporates a risk index model, leverages geographic information systems (GIS) technology, and contains a comprehensive chemical and environmental database to assess and delineate the immediate threat posed by a terrestrial chemical spill. It is designed to serve a variety of stakeholders, including managers and policy-makers, who would benefit from generating screening-level environmental risk assessments without requiring a technical background or collection of detailed environmental and chemical data. Areas of potential application include transportation routing, industrial zoning, environmental regulatory compliance and enforcement, spill response, and security planning.     

exLOPA for explosion risks assessment

The European Union regulations require safety and health protection of workers who are potentially at risk from explosive atmosphere areas. According to the requirements, the operators of installations where potentially explosive atmosphere can occur are obliged to produce an explosion protection document. The key objective of this document is the assessment of explosion risks. This paper is concerned with the so-called explosion layer of protection analysis (exLOPA), which allows for semi-quantitative explosion risk assessment for process plants where explosive atmospheres occur. The exLOPA is based on the original work of CCPS for LOPA but takes into account some typical factors appropriate for explosion, like the probability that an explosive atmosphere will occur, probability that sources of ignition will be present and become effective as well as the probability of failure on demand for appropriate explosion prevention and mitigation means.     

Lessons learned from hazardous chemical incidents--Louisiana Hazardous Substances Emergency Events Surveillance (HSEES) system

Since 2001, the Louisiana Department of Health and Hospitals (LDHH) has participated in the Hazardous Substances Emergency Events Surveillance (HSEES) system. In 2001, there were 815 events qualified for HSEES surveillance. Data for each event was gathered and analyzed. During these hazardous substances events, there were 1164 chemicals released resulting in injuries to 63 people, most with respiratory system irritation. Even though more people were injured in fixed-facility events, injuries were more likely to result from transportation-related events. The quantity and frequency of hazardous substance releases do not always positively correlate with the number of injuries sustained during those releases. A higher percentage of "Rail" transport events was observed in Louisiana when compared with other HSEES states. By collecting and analyzing more data and disseminating results to the public, it is expected that further adverse public health consequences from hazardous releases/spills in Louisiana can be reduced and/or minimized.     

密闭空间煤粉爆炸特性的实验研究

为了探明煤粉在密闭空间中的爆炸特性参数,利用20 L球形爆炸装置进行实验测试,实验研究了不同点火能量对煤粉爆炸行为的影响,对比CaCO_3和Al(OH)_3两种惰性介质的抑爆效果及惰性介质的抑爆效力随点火能量的变化规律进行了重点探讨。结果表明:随着点火能量的增加,爆炸压力随着煤粉浓度的增加呈现先上升后下降的趋势,在同一浓度下,粉尘最大爆炸压力和最大升压速率呈线性上升,在高浓度下,粉尘爆炸压力受点火能量的影响更显著;添加CaCO_3和Al(OH)_3能够降低煤粉的爆炸压力,相对于CaCO_3的物理抑爆而言,Al(OH)_3的物理-化学抑爆效果更佳;惰性介质抑爆效力随点火能量增加而下降,建议采用5~10 k J点火能量考察惰性介质对煤粉爆炸的抑制效力。     

Simulation of the cumulative effects of chemical spills using a spatial-temporal dynamics analysis algorithm

Accidents in urban areas involving chemical spills demands development of not only feasible emergency strategies, but also a consistent framework to protect the environment and prevent accidents. This can be possible only by a sound understanding of the environmental impact of spills and their potential long-term effects. Furthermore, the impact assessment of chemical spills can not be done disregarding the spatial-temporal pattern of previous exposures reciprocally influenced by both chemical and environmental properties. In this context, this paper presents an analysis framework to quantify the cumulative effects of chemical spills at any given point of a certain area based on a "present" history of exposure coupled with chemical and environmental properties to predict possible scenarios of future exposure and estimate in advance potential alarming levels of pollution. In the present circumstances when increasing knowledge is required for an accurate prediction of spill migration through unsaturated soil, this paper proposes an algorithm capable of incorporating models of increasing complexities to simulate the single-spill events once new advancements in the field are taken. The algorithm developed is illustrated using a simple model with homogenous and steady-state conditions to simulate the single-spill events. A hypothetical case study was constructed to illustrate the analysis steps and the benefits of the algorithm.     

Estimation of potential impacts and natural resource damages of oil

Methods were developed to estimate the potential impacts and natural resource damages resulting from oil spills using probabilistic modeling techniques. The oil fates model uses wind data, current data, and transport and weathering algorithms to calculate mass balance of fuel components in various environmental compartments (water surface, shoreline, water column, atmosphere, sediments, etc.), oil pathway over time (trajectory), surface distribution, shoreline oiling, and concentrations of the fuel components in water and sediments. Exposure of aquatic habitats and organisms to whole oil and toxic components is estimated in the biological model, followed by estimation of resulting acute mortality and ecological losses. Natural resource damages are based on estimated costs to restore equivalent resources and/or ecological services, using Habitat Equivalency Analysis (HEA) and Resource Equivalency Analysis (REA) methods. Oil spill modeling was performed for two spill sites in central San Francisco Bay, three spill sizes (20th, 50th, and 95th percentile volumes from tankers and larger freight vessels, based on an analysis of likely spill volumes given a spill has occurred) and four oil types (gasoline, diesel, heavy fuel oil, and crude oil). The scenarios were run in stochastic mode to determine the frequency distribution, mean and standard deviation of fates, impacts, and damages. This work is significant as it demonstrates a statistically quantifiable method for estimating potential impacts and financial consequences that may be used in ecological risk assessment and cost-benefit analyses. The statistically-defined spill volumes and consequences provide an objective measure of the magnitude, range and variability of impacts to wildlife, aquatic organisms and shorelines for potential spills of four oil/fuel types, each having distinct environmental fates and effects.     

Cost-effectiveness criteria for marine oil spill preventive measures

Oil tanker accidents resulting in large quantities of oil spills and severe pollution have occurred in the past, leading to major public attention and an international focus on finding solutions for minimising the risks related to such events. This paper proposes a novel approach for evaluating measures for prevention and control of marine oil spills, based on considerations of oil spill risk and cost effectiveness. A cost model that incorporates all costs of a shipping accident has been established and oil tanker spill accidents have been further elaborated as a special case of such accidents. Utilising this model, novel implementation criteria, in terms of the Cost of Averting a Tonne of oil Spilt (CATS), for risk control options aiming at mitigating the environmental risk of accidental oil spills, are proposed. The paper presents a review of previous studies on the costs associated with oil spills from shipping, which is a function of many factors such as location of spill, spill amount, type of oil, etc. However, ships are designed for global trade, transporting different oil qualities. Therefore, globally applicable criteria must average over most of these factors, and the spill amount is the remaining factor that will be used to measure cost effectiveness against. A weighted, global average cleanup cost of USD 16,000/tonne of oil spilt has been calculated, considering the distribution of oil tanker traffic densities. Finally, the criteria are compared with some existing regulations for oil spill prevention, response and compensation (OPA 90).     

Treatment of hazardous materials spills in flowing streams with floating mass transfer agents

Field studies were conducted in a Flowing Stream Test Facility to determine parameters governing application of floating media (in this case, commercially-available activated carbon) to flowing streams for the purpose of treating hazardous materials spills in situ. It was found that removal efficiency is highly dependent on prompt location of the contaminant plume, even dispersion of media over the water surface, and favorable environmental conditions. This technique is most effective for concentrated plumes in small streams, and removal efficiencies increase as the size of the spill increases. Removal efficiencies ranged from 50 to > 95%, depending upon the substance being used in the tests.Further investigation should focus on ballast and packaging techniques, methods for increasing efficiency of contact, prevention of carbon buildup along stream banks, and efficiency of spent carbon collection.