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U.S. military and allied contingency operations are increasingly occurring in locations with limited, unstable or compromised fresh water supplies. Non-potable graywater reuse is currently under assessment as a viable means to increase mission sustainability while significantly reducing the resources, logistics and attack vulnerabilities posed by transport of fresh water. Development of health-based (non-potable) exposure guidelines for the potential microbial components of graywater would provide a logical and consistent human-health basis for water reuse strategies. Such health-based strategies will support not only improved water security for contingency operations, but also sustainable military operations. Dose-response assessment of Vibrio cholerae based on adult human oral exposure data were coupled with operational water exposure scenario parameters common to numerous military activities, and then used to derive health risk-based water concentrations. The microbial risk assessment approach utilized oral human exposure V. cholerae dose studies in open literature. Selected studies focused on gastrointestinal illness associated with experimental infection by specific V. cholerae serogroups most often associated with epidemics and pandemics (O1 and O139). Nonlinear dose-response model analyses estimated V. cholerae effective doses (EDs) aligned with gastrointestinal illness severity categories characterized by diarrheal purge volume. The EDs and water exposure assumptions were used to derive Risk-Based Water Concentrations (CFU/100 mL) for mission-critical illness severity levels over a range of water use activities common to military operations. Human dose-response studies, data and analyses indicate that ingestion exposures at the estimated ED1 (50 CFU) are unlikely to be associated with diarrheal illness while ingestion exposures at the lower limit (200 CFU) of the estimated ED10 are not expected to result in a level of diarrheal illness associated with degraded individual capability. The current analysis indicates that the estimated ED20 (approximately 1000 CFU) represents initiation of a more advanced stage of diarrheal illness associated with clinical care.

Objective: To provide specific guidance and resources for systematic and orderly decontamination of human remains resulting from a chemical terrorist attack or accidental chemical release. Design: A detailed review and health-based decision criteria protocol is summarized. Protocol basis and logic are derived from analyses of compoundspecific toxicological data and chemical/physical characteristics. Setting: Guidance is suitable for civilian or military settings where human remains potentially contaminated with hazardous chemicals may be present, such as sites of transportation accidents, terrorist operations, or medical examiner processing points. Patients and participants: Guidance is developed from data-characterizing controlled experiments with laboratory animals, fabrics, and materiel. Main outcome measure(s): Logic and specific procedures for decontamination and management of remains, protection of mortuary affairs personnel, and decision criteria to determine when remains are sufficiently decontaminated are presented. Results: Established procedures as well as existing materiel and available equipment for decontamination and verification provide reasonable means to mitigate chemical hazards from chemically exposed remains. Unique scenarios such as those involving supralethal concentrations of certain liquid chemical warfare agents may prove difficult to decontaminate but can be resolved in a timely manner by application of the characterized systematic approaches. Decision criteria and protocols to “clear” decontaminated remains for transport and processing are also provided. Conclusions: Once appropriate decontamination and verification have been accomplished, normal procedures for management of remains and release can be followed.

In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility reuse and re-entry could require hours to multiple days. While restoration timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical terrorist release. What follows is the first of a two-part analysis identifying key considerations, critical information, and decision criteria to facilitate post-attack and post-decontamination consequence management activities. A conceptual site model and human health-based exposure guidelines are developed and reported as an aid to site-specific pre-planning in the current absence of U.S. state or Federal values designated as compound-specific remediation or re-entry concentrations, and to safely expedite facility recovery to full operational status. Chemicals of concern include chemical warfare nerve and vesicant agents and the toxic industrial compounds phosgene, hydrogen cyanide, and cyanogen chloride. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination.

The decontamination of chemical warfare agents (CWA) from structures, environmental media, and even personnel has become an area of particular interest in recent years due to increased homeland security concerns. In addition to terrorist attacks, scenarios such as accidental releases of CWA from U.S. stockpile sites or from historic, buried munitions are also subjects for response planning. To facilitate rapid identification of practical and effective decontamination approaches, this paper reviews pathways of CWA degradation by natural means as well as those resulting from deliberately applied solutions and technologies; these pathways and technologies are compared and contrasted. We then review various technologies, both traditional and recent, with some emphasis on decontamination materials used for surfaces that are difficult to clean. Discussion is limited to the major threat CWA, namely sulfur mustard (HD, bis(2-chloroethyl)sulfide), VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate), and the G-series nerve agents. The principal G-agents are GA (tabun, ethyl N,N-dimethylphosphoramidocyanidate), GB (sarin, isopropyl methylphosphonofluoridate), and GD (soman, pinacolyl methylphosphonofluoridate). The chemical decontamination pathways of each agent are outlined, with some discussion of intermediate and final degradation product toxicity. In all cases, and regardless of the CWA degradation pathway chosen for decontamination, it will be necessary to collect and analyze pertinent environmentalmore » samples during the treatment phase to confirm attainment of clearance levels.« less

/ The US Army manages an extensive program of environmental restoration that is carried out primarily under authority of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which establishes response authority for cleanup of inactive waste sites. The Resource Conservation and Recovery Act (RCRA) regulates the management and cleanup of hazardous materials at active hazardous waste facilities. Based on the definitions found in these acts, and corresponding promulgated regulations, environmental media contaminated with chemical warfare materiel (CWM) can be regulated as CERCLA "pollutants or contaminants" but do not appear to be regulated either as CERCLA hazardous substances or RCRA hazardous wastes.In those states that have not included CWM as hazardous materials in their RCRA programs, the RCRA requirements for management of hazardous waste would not strictly apply to any of the CWM. The Army has historically implemented procedures requiring that chemical warfare agents be managed as RCRA hazardous waste regardless of the concentration, physical form, or configuration of the agent. Such application of strict hazardous waste requirements to management of potentially nonhazardous CWM can result in remedial costs well out of proportion to potential human health and environmental benefits. Recent development of chronic toxicity values for the CWM has opened the door for development of cleanup and waste management standards for waste streams or media containing small residual amounts of CWM. Implementation of this health-based approach to management of CWM remediation wastes may, in part, help to reduce potentially unnecessary hazardous waste management costs for the nonhazardous CWM.

During the process of deriving oral Reference Dose (RfDs) values for chemical warfare agents, several issues arose regarding the identification of adverse effect levels and the application of uncertainty factors. For those agents that function as cholinesterase inhibitors (e.g., agents VX, GA, GB, and GD), these issues included the following: (1) Is the endpoint of blood cholinesterase inhibition an indicator of toxicity or a biomarker of exposure? (2) Can an experimental animal species be more sensitive than humans, thereby eliminating the need for an animal-to-human uncertainty factor? (3) Can the uncertainty factor that is used to extrapolate from a lowest-observed adverse-effect-level (LOAEL) to a no-observed-adverse-effect-level (NOAEL) be less than the default value of 10? (4) Can an oral RfD be derived from non-oral toxicity data? (5) Can an uncertainty factor of less than 10 be used to extrapolate from subchronic to chronic exposure (e.g., is the critical effect adequately described by the subchro...

Although not widely known, a robust set of peer-reviewed public health and occupational exposure levels presently exist for key chemical warfare agents (CWAs) and certain acutely toxic industrial chemicals (TICs) identified as terrorist attack threats. Familiarity with these CWA and TIC exposure levels and their historic applications has facilitated emergency management decision-making by public and environmental health decision-makers. Specifically, multiple air, soil, and water exposure levels for CWAs and TICs summarized here have been extensively peer-reviewed and published; many have been recognized and are in use by federal and state health agencies as criteria for hazard zone prediction and assessment, occupational safety, and “how clean is clean enough” decisions. The key, however, is to know which criteria are most appropriate for specific decisions.While public safety is critical, high levels of concern often associated with perceived or actual proximity to extremely toxic chemical agents could result in overly cautious decisions that generate excessive delays, expenditure of scarce resources, and technological difficulties. Rapid selection of the most appropriate chemical exposure criteria is recommended to avoid such problems and expedite all phases of chemical incident response and recovery.

Analytical methods for the detection of two chemical warfare agent simulants, diisopropyl methylphosphonate and chloroethylethylsulfide, in beef tissue and milk have been demonstrated to be effective to levels as low as 50–100 parts-per-billion. These methods are based upon thermal desorption into an ion trap mass spectrometer. Selective detection of the target compounds is achieved by isobutane chemical ionization in combination with collision-induced dissociation, which yields characteristic fragment ions. Rapid sample clean-up steps were also devised to reduce interferences from the sample matrix. The low detection limits achieved with this method suggest that it may be possible to take small tissue samples from livestock by needle biopsy, without requiring animal sacrifice for the analysis. In addition, because the new methods may be performed more quickly than conventional methods requiring substantial sample preparation and analysis time, more samples could be analyzed.

A measurement protocol is documented and data presented to characterize the permeation of chemical warfare agent simulants through the porous con- struction materials brick, cinder block, gypsum wall board, and wood. These data will be used to develop guidelines for access (‘reentry’) to potentially contaminated properties if nerve or vesicant agents are released during any phase of the US Department of the Army's Chemical Stock- pile Disposal Program. A novel permeation cell design allowed sampling of air volumes adjacent to the spiked face, breakthrough face and lateral face of each test medium at two temperatures. Simulant movement through wood is nearly always in the direction of the wood grain. Two-dimensional breakthrough was observed in brick and gypsum wall board. The sulfur mustard simulant broke through all test media in less than 60 min; nerve agent simulant breakthrough required several hours. Surface decontamination of wood with high test hypochlorite is 95% effective.

The initial development is reported for a novel countercurrent filtration/dialysis and solid phase extractant system for the rapid isolation of low molecular weight target compounds from biological media. Except for piperazine (a highly water-soluble drug), recoveries of 50–85% were achieved for chemical warfare agent simulants and anthelmintic drugs extracted from meat, grain, or milk. The results suggest the potential for broad applications to complex samples such as environmental media and physiological specimens which traditionally require extensive fractionation prior to analysis. Research sponsored by U.S. Department of Energy, Office of Energy Research, under contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc., U.S. Food and Drug Administration and U.S. Department of the Army.

Effective procedures associated with storage and disposal of chemical warfare (CW) agents are important for the protection of civilian populations from inadvertent release of these agents. Emergency groups as well as citizens in surrounding communities need to know the relative effectiveness of various chemical protective clothing (CPC) ensembles in the unlikely event of such releases. A method has been developed for studying permeation of chemical warfare agent simulants through CPC materials. The experimental results characterize some commercially available CPC materials. Thirteen different CPC materials having widely differing compositions were chosen to study the permeation of four different liquid CW simulants (dimethyl methyl phosphonate, diisopropyl methyl phosphonate, malathion, and dibutyl sulfide) through these CPC materials at 25 °C. This permeation study involved a newly developed analytical technique employing room temperature fluorescence quenching of an indicator compound, phenanthrene, on filter paper. Various experimental factors such as breakthrough time, rate of permeation and uptake were investigated. On the basis of breakthrough time, the 13 CPC materials could be divided into three groups: most resistant, moderately resistant, and least resistant. Materials in the most resistant category exhibited no permeation by any of the simulants for at least 24 hours. Breakthrough occurred in the least resistant materials in generally less than an hour, and sometimes as soon as a few minutes.

In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility re-use and re-entry could require hours to multiple days. While timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical release. What follows is the second of a two-part analysis identifying key considerations, critical information and decision criteria to facilitate post-attack and post-decontamination consequence management activities. Decision criteria analysis presented here provides first-time, open-literature documentation of multi-pathway, health-based remediation exposure guidelines for selected toxic industrial compounds, chemical warfare agents, and agent degradation products for pre-planning application in anticipation of a chemical terrorist attack. Guideline values are provided for inhalation and direct ocular vapor exposure routes as well as percutaneous vapor, surface contact, and ingestion. Target populations include various employees as well as transit passengers. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination.

In the event of an unplanned release of a chemical warfare agent during any stage of the Chemical Stockpile Disposal Program, the potential exists for off-post contamination of drinking water, forage crops, grains, garden produce, and livestock. The more persistent agents, such as the organophosphate nerve agent VX, pose the greatest human health concern for reentry. A relative potency approach comparing the toxicity of VX to organophosphate insecticide analogues is developed and used to estimate allowable residues for VX in agricultural products and reentry intervals for public access to contaminated areas. Analysis of mammalian LD50 data by all exposure routes indicates that VX is 10(3) to 10(4) times more toxic than most commercially available organophosphate insecticides. Thus, allowable residues of VX could be considered at concentration levels 10(3) to 10(4) lower than those established for certain insecticides by the U.S. EPA. Evaluation of reentry intervals developed for these organophosphate analogues indicate that, if environmental monitoring cannot reliably demonstrate acceptable levels of VX, restricted access to suspect or contaminated areas may be on the order of weeks to months following agent release. Planning for relocation, mass care centers, and quarantine should take this time period into account.

The current analysis characterizes chemical protective clothing (CPC) that would be available to civilian emergency personnel responding to possible ne

A protocol Is described to determine whole-blood cholinesterase activity using an automated highspeed centrifugal analyzer. Throughput rate was increased 10-fold (from 6 to 60 samples/h), and precision, as measured by a reduction In Intra-allquot variation, was significantly Improved (from 4.7 to 3.0%) by using an automated system rather than a manual system. Similar cholinesterase activity was determined for samples analyzed by both the automated and manual protocols, and Interlaboratory comparison Indicated no change In accuracy. The lower limit of detection was estimated to be 0.10 μmol/mL/mln. The 10-fold Increase In throughput facilitates use of the automated protocol when many analyses must be performed in a limited time.

The vesicant agents of the unitary chemical munitions stockpile include various formulations of sulfur mustard [bis-(2-chloroethyl) sulfide; agents H, HD, and HT] and small quantities of the organic arsenical Lewisite [dichloro(2-chlorovinyl) arsine; agent L]. These agents can be dispersed in liquid, aerosol, or vapor form and are capable of producing severe chemical burns upon direct contact with tissue. Moist tissues such as the eyes, respiratory tract, and axillary areas are particularly affected. Available data summarizing acute dose response in humans and laboratory animals are summarized. Vesicant agents are also capable of generating delayed effects such as chronic bronchitis, carcinogenesis, or keratitis/keratopathy of the eye under appropriate conditions of exposure and dose. These effects may not become manifest until years following exposure. Risk analysis derived from carcinogenesis data indicates that sulfur mustard possesses a carcinogenic potency similar to that of benzo[a]pyrene. Because mustard agents are alkylating compounds, they destroy individual cells by reaction with cellular proteins, enzymes, RNA, and DNA. Once begun, tissue reaction is irreversible. Mustard agents are mutagenic; data for cellular and laboratory animal assays are presented. Reproductive effects have not been demonstrated in the offspring of laboratory rats. Acute Lewisite exposure has been implicated in cases of Bowen's disease, an intraepidermal squamous cell carcinoma. Lewisite is not known to generate reproductive or teratogenic effects.

This report evaluates whether new information and updated scientific models require that changes be made to previously published health-based environmental soil screening levels (HBESLs) and associated environmental fate/breakdown information for chemical warfare agents (USACHPPM 1999). Specifically, the present evaluation describes and compares changes that have been made since 1999 to U.S. Environmental Protection Agency (EPA) risk assessment models, EPA exposure assumptions, as well as to specific chemical warfare agent parameters (e.g., toxicity values). Comparison was made between screening value estimates recalculated with current assumptions and earlier health-based environmental screening levels presented in 1999. The chemical warfare agents evaluated include the G-series and VX nerve agents and the vesicants sulfur mustard (agent HD) and Lewisite (agent L). In addition, key degradation products of these agents were also evaluated. Study findings indicate that the combined effect of updates and/or changes to EPA risk models, EPA default exposure parameters, and certain chemical warfare agent toxicity criteria does not result in significant alteration to the USACHPPM (1999) health-based environmental screening level estimates for the G-series and VX nerve agents or the vesicant agents HD and L. Given that EPA's final position on separate Tier 1 screening levels for indoor and outdoor worker screening assessmentsmore » has not yet been released as of May 2007, the study authors find that the 1999 screening level estimates (see Table ES.1) are still appropriate and protective for screening residential as well as nonresidential sites. As such, risk management decisions made on the basis of USACHPPM (1999) recommendations do not require reconsideration. While the 1999 HBESL values are appropriate for continued use as general screening criteria, the updated '2007' estimates (presented below) that follow the new EPA protocols currently under development are also protective. When EPA finalizes and documents a position on the matter of indoor and outdoor worker screening assessments, site-specific risk assessments should make use of modified models and criteria. Screening values such as those presented in this report may be used to assess soil or other porous media to determine whether chemical warfare agent contamination is present as part of initial site investigations (whether due to intentional or accidental releases) and to determine whether weather/decontamination has adequately mitigated the presence of agent residual to below levels of concern. However, despite the availability of scientifically supported health-based criteria, there are significant resources needs that should be considered during sample planning. In particular, few analytical laboratories are likely to be able to meet these screening levels. Analyses will take time and usually have limited confidence at these concentrations. Therefore, and particularly for the more volatile agents, soil/destructive samples of porous media should be limited and instead enhanced with headspace monitoring and presence-absence wipe sampling.« less

Chemical Warfare Agents, Second Edition has been totally revised since the successful first edition and expanded to about three times the length, with many new chapters and much more in-depth consideration of all the topics. The chapters have been written by distinguished international experts in various aspects of chemical warfare agents and edited by an experienced team to produce a clear review of the field. The book now contains a wealth of material on the mechanisms of action of the major chemical warfare agents, including the nerve agent cyclosarin, formally considered to be of secondary importance, as well as ricin and abrin. Chemical Warfare Agents, Second Edition discusses the physico-chemical properties of chemical warfare agents, their dispersion and fate in the environment, their toxicology and management of their effects on humans, decontamination and protective equipment. New chapters cover the experience gained after the use of sarin to attack travelers on the Tokyo subway and how to deal with the outcome of the deployment of riot control agents such as CS gas. This book provides a comprehensive review of chemical warfare agents, assessing all available evidence regarding the medical, technical and legal aspects of their use. It is an invaluable referencemore » work for physicians, public health planners, regulators and any other professionals involved in this field.« less

Acute exposure guideline levels (AEGLs) have been developed for the chemical warfare agents GB, GA, GD, GF, VX, and sulfur mustard. These AEGLs were approved by the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances after Federal Register publication and comment, and judged as scientifically valid by the National Research Council Committee on Toxicology Subcommittee on AEGLs. AEGLs represent general public exposure limits for durations ranging from 10 min to 8 h, and for three levels of severity (AEGL-1, AEGL-2, AEGL-3). Mild effects are possible at concentrations greater than AEGL-1, while life-threatening effects are expected at concentrations greater than AEGL-3. AEGLs can be applied to various civilian and national defense purposes, including evacuation and shelter-in-place protocols, reentry levels, protective clothing specifications, and analytical monitoring requirements. This report documents development and derivation of AEGL values for six key chemical warfare agents, and makes recommendations for their application to various potential exposure scenarios.

Publisher Summary Chemical warfare nerve agents are potent anticholinesterase compounds deliberately formulated to induce debilitating effects or death during wartime hostilities. Because of their steep dose response, these agents have been used by military authorities of several nations to develop munitions, and have been deployed by certain domestic terrorists. A key need for both community emergency preparedness and installation restoration is the availability of health-based exposure guidelines derived in a transparent manner by contemporary methods of data analysis. The chapter summarizes guidelines for acute vapor and chronic ingestion exposure to the nerve agents, GA (tabun), GB (satin), GD (soman), GF (cyclosarin), and VX. The toxicological analysis and logic incorporated into the estimation of reference dose (RfDe), and AEGL values for these nerve agents employ standard protocols to govern management of Superfund sites, and extremely hazardous substances unintentionally released during industrial accidents or chemical spills. In addition, both parameters are considered critical to maintaining compliance with international treaty obligations governing the stockpile and destruction of chemical weapons. The nerve agent RfDe and AEGL values, are now available for application to civilian and military defense purposes, such as shelter-in-place and evacuation protocols, recovery and remediation levels, analytical monitoring requirements, and protective clothing specifications. These guidelines are intended to preserve public health by not only characterizing potentially harmful exposure levels, but also identifying levels at which minimal or no toxic effects are expected. The toxicological analyses, protocol, and logic incorporated into nerve agent chronic RfDe and AEGL guideline development are documented, and their recent use by civilian and military authorities is summarized.

A 1998 paper published in Reviews in Environmental Contamination and Toxicology (Opresko et al. 1998) documented the development of oral reference doses (RfDs) for several groups of chemical warfare agents; i.e., sulfur mustard agents, nitrogen mustard agents, organophosphate nerve agents, the arsenical lewisite, and cyanogen chloride. The development of these reference doses was initiated by the U.S. Army Environmental Center (USAEC) to support its continuing task of remediating sites potentially contaminated by past releases of hazardous substances. This action was taken under general provisions of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). The USAEC, which functions as the program manager for the Army’s Installation Restoration Program (IRP), determined that responsible and efficient cleanup of both active installations and formerly used defense sites (FUDS) contaminated with chemical warfare agent residues required key toxicological parameters for performing IRP site health risk assessments.

The FY 1993 Defense Authorization Act [Public Law (PL) 102–484, Sect. 176] directed the U.S. Department of the Army (DA) 1 to examine the scale of effort and consider plans needed to safely dispose of nonstockpile chemical materiel (NSCM), previously identified as an area of national concern in House Appropriations Report 101–822 from the FY 1991 Defense Appropriations Act. Non-stockpile chemical materiel is defined in the Appropriations Report as “… lethal wastes from past disposal efforts, unserviceable munitions, chemically contaminated containers, chemical production facilities, subsequently located chemical munitions, sites known to contain significant concentrations of buried chemical weapons and waste, and binary weapons and components.” Items considered NSCM are further characterized as chemical materiel outside of the U.S. retaliatory stockpile of lethal chemical agents and munitions (described more fully in Carnes and Watson 1989; DA 1988).

In the event of an unplanned release of chemical warfare agent during any phase of the Chemical Stockpile Disposal Program (CSDP), a (small) potential exists for contamination of buildings and materials used in their construction. Guidelines for unrestricted access to potentially agent-contaminated private and public property are presently undefined due to uncertainties regarding the adequacy of decontaminating porous surfaces such as wood, masonry and gypsum wall board. Persistent agents such as VX or mustard are particularly problematic. The report which follows documents a measurement protocol developed in a scoping investigation characterizing the permeation of chemical warfare agent simulants [diisopropylmethyl phosphonate (DIMP) for warfare agent GB, dimethylmethyl phosphonate (DMMP) for warfare agent VX and chlorethylethyl sulfide (CEES) for warfare agent sulfur mustard] through several, common porous, construction materials. The ``porous media`` selected for examination were wood, brick, cinder block, and gypsum wall board. Simulants were tested rather than actual warfare agents because of their low toxicity, commercial availability, and the lack of surety capability at Oak Ridge National Laboratory (ORNL). The present work is considered a protocol for confirmation testing with ``live`` agents.

Four arsenicals including organic and inorganic forms of both the trivalent and pentavalent states were tested for their potential environmental effect on a nontarget animal species. Cacodylic acid, cacodylic acid plus sodium cacodylate, arsenic trioxide, and arsenic pentoxide were evaluated in terms of formulation, exposure time, and tissue arsenic concentrations on the survival of an exposed population of meadow katydids. Tissue concentrations of elemental arsenic were higher for organic forms than for inorganic forms at similar exposure dosages. Life expectancies were reduced to less than 10 percent of unexposed populations by levels above 5 ..mu..g As/g dry weight in dosing formulations. While As concentrations in katydid tissues did not exceed those in the dosing formulations, they did exceed tissue concentrations found in unexposed populations by as much as three orders of magnitude. These results illustrate the impact of herbicidal arsenic formulations on a nontarget animal species.

An evaluation of potential occupational and public health aspects of geopressure, hydrothermal, hot dry rock, silviculture, crop and animal residues, fermentable plant products, municipal waste, and plantation energy technologies has been performed. Future development of these energy options in the United States will contain hazards that could easily be eliminated by safer equipment design and common-sense attention to operation and maintenance. Occupational exposure to hydrogen sulfide gas occurs near all geothermal sites and wherever organic matter decomposes anaerobically. Respiratory damage has occurred to laborers in geothermal fields, while farm workers have been fatally overcome when employed near agitating liquid manure systems. However, the most frequent and severe of reported injuries to geothermal workers is dermal exposure to caustic sludges produced by H2S abatement systems. Principal health and safety considerations of biomass pathways are directly related to the diffuse nature of solar energy fixation by photosynthesis and subsequent transfer to animal food chains. Since the potential fuel is in an unconcentrated form, cultivation, harvest, and transport are necessarily laborintensive. Thus, a significant potential for occupational injuries and fatalities exists. Of all biomass systems evaluated, direct burning of solid fuels presents the greatest public health risk. Data are presented to characterize the population at risk and the frequency and severity of injuries.

This paper reviews both innovative fossil energy sources (tar sands, oil shale, and unconventional natural gas), and more established technologies that are being considered as suppliers of gaseous and liquid fuels (that is, coal gasification and liquefaction). Potential health and safety issues related to the technologies are discussed, although the absence of commercial-scale facilities in the United States restricts the discussion to health effects information derived from related processes. The available epidemiological and carcinogenic studies give cause for concern. The study of the health and environmental impacts of the emerging fossil fuel technologies will be important for quantification of adverse effects and rectification of problems before commitment to large-scale commercialization occurs.

A relative potency method for assessing potential human health effects from exposures to relatively untested chemicals is presented and documented. The need for such a method in evaluating the carcinogenic potential of the chemical warfare agent sulfur mustard (agent HD) from a limited data base is specifically addressed. The best-estimate potency factor for sulfur mustard relative to benzo[a]pyrene is 1.3, with an interquartile range of 0.6 to 2.9. The method is applied to (1) the estimated fence-boundary air concentrations of mustard during operation of a proposed agent incinerator at Aberdeen Proving Ground (APG), Maryland, and (2) the current approved general population exposure level of 1 X 10(-4) mg HD/m3 and the occupational exposure level of 3 X 10(-3) mg HD/m3. Maximum estimates of excess lifetime cancer risk for individuals at sites along the APG boundary range between 3 X 10(-8) and 1 X 10(-7). Lifetime cancer risk estimates less than or equal to 10(-6) are not now regulated by the U.S. Environmental Protection Agency or the Food and Drug Administration. Maximum estimates of excess lifetime cancer risk assuming daily exposure to the approved standards during the proposed 5 years of incinerator operation are on the order of 10(-5) for the general public and 10(-4) for the worker population. These values are considered upper limit estimates.

No energy technology is risk free when all aspects of its utilization are taken into account. Every energy technology has some attendant direct and indirect health and safety concerns. Solar technologies examined in this paper are wind, ocean thermal energy gradients, passive, photovoltaic, satellite power systems, low- and high-temperature collectors, and central power stations, as well as tidal power. For many of these technologies, insufficient historical data are available from which to assess the health risks and environmental impacts. However, their similarities to other projects make certain predictions possible. For example, anticipated problems in worker safety in constructing ocean thermal energy conversion systems will be similar to those associated with other large-scale construction projects, like deep-sea oil drilling platforms. Occupational hazards associated with photovoltaic plant operation would be those associated with normal electricity generation, although for workers involved in the actual production of photovoltaic materials, there is some concern for the toxic effects of the materials used, including silicon, cadmium, and gallium arsenide.