A framework for integrating information resources for chemical emergency management and response

Abstract

Effective emergency management and response require appropriate utilization of various resources as an incident evolves. This manuscript describes the information resources used in chemical emergency management and operations and how their utility evolves from the initial response phase to recovery to event close out. The authors address chemical hazard guidance in the context of four different phases of emergency response: preparedness, emergency response (both initial and ongoing), recovery, and mitigation. Immediately following a chemical incident, during the initial response, responders often use readily available, broad-spectrum guidance to make rapid decisions in the face of uncertainties regarding potential exposure to physical and health hazards. Physical hazards are described as the hazards caused by chemicals that can cause harm with or without direct contact. Examples of physical hazards include explosives, flammables, and gases under pressure. This first line of resources may not be chemical-specific in nature, but it can provide guidance related to isolation distances, protective actions, and the most important physical and health threats. During the ongoing response phase, an array of resources can provide detailed information on physical and health hazards related to specific chemicals of concern. Consequently, risk management and mitigation actions evolve as well. When the incident stabilizes to a recovery phase, the types of information resources that facilitate safe and effective incident management evolve. Health and physical concerns transition from acute toxicity and immediate hazards to both immediate and latent health effects. Finally, the information inputs utilized during the preparedness phase include response evaluations of past events, emergency preparedness planning, and chemical-specific guidance about chemicals present. This manuscript details a framework for identifying the effective use of information resources at each phase and provides case study examples from chemical hazard emergencies.

Introduction

Federal and state Occupational Safety and Health Administration (OSHA)-mandated requirements for hazardous materials responders are found in 29 CFR 1910.120. OSHA characterizes responders to community-based hazardous materials emergencies into five levels: (1) First Responder—Awareness, (2) First Responder—Operational, (3) Technician, (4) Specialist, and (5) On-Scene Incident Commander. All levels need to be aware of and be able to identify any potential health and physical hazards. Responders benefit from effective health and safety information tools, because not all responders will have the necessary expertise to handle specialized events. The speed at which a responder can gather information from a resource is crucial in emergency response. Because multiple, sometimes unknown hazards can be present, effective responses to chemical hazard emergencies require specialized and comprehensive information. Conditions in such events are dynamic and change rapidly, presenting a need for ongoing assessment and frequent re-evaluation. This article outlines (1) elements of a process for systematic information resource selection and management, based on emergency management and response (EMR) phases; (2) features of resources that affect the identification and selection of appropriate information sources for controlling health and safety hazards of chemicals; (3) consideration for integrating physical and health hazard information to develop a cohesive risk management and mitigation approach; and (4) application of these concepts in emergency chemical incidents.

The need for strategic approaches to emergency management is demonstrated by the various efforts to develop resources that aid responders and incident command staff during emergency events. For instance, the National Incident Management System (NIMS) was developed by the Federal Emergency Management Agency (FEMA) as a comprehensive, national approach to risk management.^1-3

A variety of resources have been developed to aid in decision making during emergency events that involve potential exposure to hazardous chemicals. As a tool for weighing information utility, available resources can be characterized on the basis of how quickly they provide information, how specific they are in describing the hazards, and how prescriptive they are in terms of risk assessment, risk management, and risk mitigation procedures. For example, initial responders to chemical incidents often favor the Emergency Response Guidebook (ERG) of the US Department of Transportation (DOT) because it helps them make decisions quickly.^4,5 Within minutes of accessing the ERG, responders obtain information regarding protective actions, isolation distances, personal protective equipment (PPE), and the most significant acute risk and hazard information associated with the hazardous materials involved. The ERG offers broad-spectrum guidance on families of chemicals, whereas other resources might offer more comprehensive chemical-specific information.

Another example of a ready resource is the NIOSH Pocket Guide to Chemical Hazards⁶ that presents chemical-specific information such as physical properties, occupational exposure limits (OELs), chemical incompatibility and reactivity, exposure routes, and respiratory protection recommendations. The array of resources vary in the type of guidance and level of specificity regarding response and risk management and mitigation measures for a unique combination of hazards presented by a scenario of interest. Because emergency management evolves over time, the resources used to design risk management and mitigation strategies change as scenarios develop and as new information becomes available. Thus, an information management strategy is essential to ensure that the most appropriate resources are provided for decision making.

Purpose

An abundance of both broad-spectrum and chemical-specific information sources exist and can be important resources during an emergency. The purpose is to present a conceptual framework for the effective and timely utilization of such critical resources throughout the various stages of a chemical incident. This framework is intended to assist emergency management personnel in making rapid, life-saving decisions in a logical and intentional manner. The framework incorporates thoughtful consideration of the evolving nature of EMR to identify which resources are most appropriate based on the phase of the response. Furthermore, the evaluation, prioritization, and integration of the resulting information is described.

EMR phases

Emergency management is a dynamic process reflecting responses that evolve as new information becomes available. An emergency event may be characterized by activities related to each phase: preparedness, emergency response (initial and ongoing), recovery, and mitigation (Figure 1).

Figure 1.

Phases of emergency management.

Mitigation is described here and elsewhere in the literature as a phase for simplicity, but can also be viewed as an action that happens throughout the emergency response process. For example as described in the glossary for the FEMA’s Incident Command System,⁷ “Mitigation measures may be implemented prior to, during, or after an incident” and “Mitigation involves ongoing actions to reduce exposure to, probability of, or potential loss from hazards.” The phases are interconnected by information that flows from one step to the next to support the various risk management and mitigation actions that are deployed (Figure 2). In this context, we use the term risk mitigation (Figure 2) in the broader sense of taking actions at various phases to reduce risks, and note that there is some overlap with the concept of risk management. For example, National Fire Protection Association (NFPA) guidance referenced in the NIMS approach defines risk management as: “The process of planning, organizing, directing, and controlling the resources and activities of an organization in order to minimize detrimental effects on that organization.”⁸ Some use the term risk management, rather than mitigation to define nearer term action during the response phase. Since we are interested in the full range of actions at each phase, we use the phrase risk management and mitigation in this article.

Figure 2.

Flow of information before, during, and after an emergency incident. (Acronyms are defined in Table 1.)

With the occurrence of an incident, the initial response begins via emergency notification. The initial Emergency Response phase includes activities related to characterizing the scenario. Once the basics of the scenario are understood, risk management and mitigation activities are further implemented. With information from rapid EMR guidance resources (general or scenario-specific), response can be rapidly deployed as a result of preparedness activities relevant to the incident. The ongoing Emergency Response phase is characterized by additional chemical- and scenario-specific information related to the event that is accessed as time passes. This information is used to refine the initial risk management and mitigation response activities. As the incident stabilizes, the EMR transitions to a Recovery phase. The transition in information resources shifts from primary concern for emergency exposures to consideration of exposures and hazardand risk-characterization tools relevant to recovery and cleanup activities. At each transition among the response and recovery phases, new information on physical and health hazards becomes available and is integrated to improve the safety profile and efficacy of the risk management and mitigation activities. Data collected from the incident are analyzed to evaluate the response and become important information for the Preparedness phase, used to guide rapid responses in future similar scenarios. A hallmark of this iterative process is the effective use of information, as each phase in the process has unique information resource needs. Several recommended information resources used in each phase are provided in Table 1. Examples of actions that occur at each phase are found in the two case studies described in this manuscript.

Table 1.

Examples of common rapidly available emergency management resources

Resource	Source	Description	Primary emergency management phase(s)
Call-in resources
Canadian Transport Emergency Centre (CANUTEC)	Transportation of Dangerous Goods Directorate of Transport Canada	CANUTEC is a safety program established in 1979 to promote public health through the safe movement of goods throughout Canada. A free, 24-hour emergency telephone hotline is available for emergency events involving dangerous goods.	Initial response
Agency for Toxic Substances and Disease Registry (ATSDR) Information Center	ATSDR	ATSDR is a public health agency that makes recommendations to the Environmental Protection Agency (EPA) regarding hazardous materials and community health. The agency has an emergency response team on duty to provide technical assistance related to health issues caused by hazardous chemical releases. ATSDR also provides a resource list of databases and toll-free numbers to gather specific information regarding chemical hazard events.	Ongoing response
Centers for Disease Control and Prevention’s National Contact Center (CDC-INFO)	CDC	CDC-INFO is a resource used to provide timely, accurate, and science-based information on a variety of public health topics. CDC-INFO consists of several communication channels, including email, phone, and postal mail.	Ongoing response
Poison Help Line	American Association of Poison Control Centers (AAPCC)	The 55 poison control centers in the United States offer 24/7 medical advice related to the prevention and treatment of poison exposures.	Ongoing response
Chemical Transportation Emergency Center (CHEMTREC)	American Chemistry Council	CHEMTREC serves as a 24/7 database for emergency response information provided by members and other subscribers. It also has a large database of SDSs. CHEMTREC is linked to the largest network of chemical and hazardous material experts in the world, including chemical and response specialists, public emergency services, and private contractors.	Initial response, ongoing response
Rapid response resources and manuals
Emergency Response Guidebook (ERG)	Department of Transportation	The ERG, which is updated every 3–5 years by DOT, is considered the general guide to use for the first 30 minutes of an emergency response. A hard copy of the ERG is provided to every public emergency response vehicle nationwide. The ERG provides exposure levels, chemical information, and physicochemical properties.	Initial response, ongoing response
NFPA Fire Protection Guide to Hazardous Materials	National Fire Protection Association	This Guide includes four NFPA documents:  • NFPA 491: Guide for Hazardous Chemical Reactions9  • NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response10  • NFPA 49: Hazardous Chemicals Data11  • NFPA 325: Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids12	Initial response, ongoing response
NIOSH Pocket Guide to Chemical Hazards (NPG)	National Institute for Occupational Safety and Health	The NPG is intended as a source of general information on several hundred chemicals/classes that may be useful in an emergency response. It presents key information and data in abbreviated or tabular form. The NPG helps users recognize and control occupational chemical hazards.	Initial response, ongoing response
Safety Data Sheets (SDSs)	Provided by manufacturers	As required by OSHA’s Hazard Communication Standard (HCS), employers must ensure that SDSs are aligned with GHS and are readily accessible to employees. As of June 1, 2015, the HCS requires new SDSs to be in a uniform format and include information on all hazards regarding the chemical, OELs, first aid measures, fire-fighting measures, emergency procedures, appropriate PPE, proper methods of containment and cleanup, incompatibilities, physicochemical properties, chemical stability and possibility of hazardous reactions, and toxicological information.	Initial response, ongoing response
Online and downloadable information resources
Wireless Information System for Emergency Responders (WISER)	US National Library of Medicine (NLM)	WISER provides a wide range of information on hazardous substances, including substance identification support, physical characteristics, human health information, and containment and suppression guidance. WISER data come from the Hazardous Substances Data Bank (HSDB). All data are referenced and derived from a core set of books, government documents, technical reports, and selected primary journal literature.	Initial response, ongoing response
Chemical Hazards Emergency Medical Management (CHEMM)	US Department of Health & Human Services	CHEMM is a web-based resource that is also downloadable in advance. It may assist in planning for, responding to, recovering from, and mitigating the effects of mass-casualty incidents involving chemicals.	Ongoing response, recovery, preparedness
Computer-Aided Management of Emergency Operations (CAMEO)	EPA’s Office of Emergency Management (OEM) and the National Oceanic and Atmospheric Administration Office of Response and Restoration (NOAA)	CAMEO is a system of software applications used to plan for and respond to chemical emergencies. The CAMEO software suite consists of four core programs: CAMEOfm, CAMEO Chemicals, ALOHA, and MARPLOT. CAMEOfm is a database application that includes several modules to assist with data management requirements under the Emergency Planning and Community Right-to-Know Act (EPCRA). CAMEO Chemicals is a program that allows users to search for chemicals in the CAMEO chemical database, print customized reports with response recommendations, and find out how chemicals would react if they mixed. ALOHA is a modeling application that estimates threat zones associated with hazardous chemical releases, including toxic gas clouds, fires, and explosions. MARPLOT is a mapping program with which one can view and modify maps.	Ongoing response, preparedness
Emergency Response Safety and Health Database (ERSH-DB)	National Institute for Occupational Safety and Health	ERSH-DB contains information on chemical, biological, and radiological agents that could be encountered following a terrorist event.	Ongoing response, preparedness
In-depth internet resources
TOXNET	US National Library of Medicine	TOXNET is a resource used to gather in-depth toxicological information related to hazardous chemicals, environmental health, and toxic releases. TOXNET allows the user to quickly search multiple databases for comprehensive chemical-specific information.	Ongoing response, preparedness

Initial emergency response phase

The initial response phase of emergency management is often characterized by dealing with hazards in the face of uncertainty.¹³ The responder must first evaluate the incident, determine its cause and origin, and work to minimize the impact of the incident by employing procedures that will preserve life and property. Preparedness and pre-planning enable rapid response with use of information directly relevant to the scenario. In the absence of a ready plan for response, alternative sources of rapid guidance are needed to quickly engage in response activities.¹⁴ Risk management actions taken during initial response reflect the general guidance provided by these rapid resources. These actions include evacuation, search and rescue, fire extinguishment, containment of hazardous materials, implementation of protective actions, distribution of information to the public, and management of fatalities.⁵ One of the most commonly used rapid ERM resources is the ERG.¹⁵ The ERG is intended for use during and immediately following an emergency incident to quickly provide critical information during the initial response.

A limitation of rapid guidance is that information may not be specific to the unique hazards of every chemical and scenario. For example, the guide used for benzene in the ERG is Guide 130: Flammable Liquids (non-polar/water-immiscible/noxious), which includes broad-spectrum acute health information such as “May cause toxic effects if inhaled or absorbed through skin” and “Vapors may cause dizziness or suffocation.” The information presented is for a broad category of flammable liquids and does not contain specific health effects related to acute benzene exposure, such as acute anemia. Furthermore, because the focus of rapid EMR guidance is on short-term effects of chemical exposures, the information does not necessarily address latent health effects. ERG Guide 130 lacks information on latent health information specific to benzene, such as the ability of the chemical to damage bone marrow and cause leukemia in those chronically exposed. Rapid EMR guidance also does not include chemical-specific guidance on medical management for those exposed to toxic chemicals. The ERG does provide the Chemical Transportation Emergency Center (CHEMTREC) number and other chemical identifiers that help the user locate more specific information from other resources or from the manufacturer that can improve risk management and mitigation actions during an ongoing response.

In addition to paper-based resources, an increasing amount of resources are available online and on mobile devices because of technological advances. Rapid electronic resources such as the Wireless Information System for Emergency Responders (WISER) (see http://wiser.nlm.nih.gov/) and the Chemical Hazards Emergency Medical Management (CHEMM) information resource (see https://chemm.nlm.nih.gov/), among others are frequently used by responders, demonstrating a trend toward the availability of more comprehensive chemical-specific information in the earliest phases of emergency response.

Ongoing phase

The risk management and mitigation strategies for an incident evolve as the incident command system gains additional information. During the ongoing response, responders and support experts often actively gather chemical-specific information on physical and health hazards and recommended response strategies. The sources of such information are diverse in terms of accessibility and content (Table 1). Useful information can come from books and printed materials; electronic databases (offline and internet-based); telephone information services; and other documentation such as right-to-know-forms and manifests.¹⁶ Because the landscape of information is complex and the need for quick access to reliable information is still a priority in the ongoing response phase, an information resource management plan is recommended. This management plan needs to include an approach for ensuring that up to date resources are maintained—particularly as reliance on internet-based resources grows. Examples of rapidly accessible and chemical-specific resources that cover physical hazards, health hazards, and risk mitigation techniques include hazard labeling and classification systems, telephone information services, and electronic resources (online and downloaded).

In the United States, hazard classification systems have been developed for guidance on physical and health hazards for transportation (DOT), fire protection (NFPA), and worker safety (OSHA and the Hazardous Materials Identification System [HMIS]). Other systems used internationally are the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and the European Intermodal Container Hazard Classification System. GHS is an international system that uses hazard phrases and pictograms to identify chemical and physical hazards. These pictograms and hazard classifications are placed on packages containing the material and on the safety data sheets (SDSs). DOT and OSHA have been aligned to GHS to provide a harmonized system of labeling and hazard communication. In the transportation system, there is a Precedence of Hazards, where toxic or water reactive labels are always primary when multiple hazards are present. The purpose of the NFPA system is to provide a simple, readily recognized, easily understood system of markings that conveys a general idea of the hazards of a material and the severity of these hazards as they relate to emergency response. A numbering system from 0 to 4 is used to indicate the degree of hazard for toxicity, flammability, and reactivity, where 4 is the highest hazard and 0 indicates no significant hazard. The appropriate ratings are posted in areas where hazardous materials are handled or stored to help identify hazards in the event of a fire. The HMIS labels are similar to NFPA labels and are used as warnings on packaged chemicals and typically on the SDSs. Both NFPA and HMIS workplace labels are frequently observed in US workplaces. Both systems are geared toward simple, rapid recognition of chemical hazards, with the “NFPA hazard diamond” directed at emergency responders and the HMIS label targeted toward employees who work with chemicals. It is important to note that from the emergency response point of view, in the GHS rating system (DOT Hazardous Materials Regulation, OSHA Hazard Communication Standard [HCS]; see 29 Code of Federal Regulations [CFR] Part 1910.1200), number 1 is for the most severe hazard (ie, a smaller number means more hazardous). However, in HMIS/NFPA, number 0 is for a minimal hazard and number 4 is for the most severe hazard, which is the opposite of the GHS system. During an ongoing response, because multiple labeling systems might be encountered, knowing their definitions and distinctions is critical.

Labels noted on containers or vessels during an incident may be helpful for general hazard recognition and as categorical descriptors of degree of hazard. The ability to weigh relative levels of concern for different hazard categories distinguishes these systems from general risk-based guidance used in initial responses. However, the presence of a label such as the NFPA diamond still does not yield chemical-specific recommendations for health hazards (eg, the nature of toxic effects) or risk management mitigation actions (eg, specific chemical protective clothing selection guides or medical treatment protocols; storage and entry requirements). Hazard classification data can often be rapidly supplemented with information from emergency response contact services if the identity of the chemical is known from placard numbers, chemical inventories, SDSs, or transportation manifest documents. Telephone information services usually provide 24-hour access to information on hazardous materials; these include the CHEMTREC, Canadian Transport Emergency Centre (CANUTEC), National Response Center, Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention’s National Contact Center (CDC-INFO), and Poison Control Centers. Increasingly, electronic resources are serving as important tools for the response phase activity. Increased access, driven by technology, has improved the utility of such resources for information needs in a short period of time. These resources often provide more comprehensive and chemical-specific information on physical and chemical properties, flammability and reactivity, health hazards and exposure limits, and risk mitigation actions. Well-used free online tools include the Computer-Aided Management of Emergency Operations (CAMEO) software suite, WISER, and CHEMM. In general, such resources provide compilations of useful information, but decision support systems are needed to aid users in selecting the best information for their scenario.¹⁷ This consideration impacts most areas of the EMR activity, but the identification and selection of exposure guidelines described below highlight the considerations involved.

A suite of chemical-specific emergency exposure limit values for health hazards influences the evolution of the risk management and mitigation strategy. Early stages of this phase would be characterized by initial efforts to gather data on airborne concentrations of chemicals involved in the release. The use of such data requires an exposure guideline or benchmark as a comparator to estimate risks and thus determine risk management and mitigation needs. Such approaches based on scenario-specific data are more specific than the general recommendations available in rapid resources such as the ERG. Challenges faced by incident commanders in trying to refine activities on the basis of measured or modeled airborne exposure estimates relate to the availability of multiple exposure guidelines for a chemical or, conversely, the absence of a guide value for a chemical of concern. An important activity in the preparedness phase that can support exposure limit selection during the response phases is developing a documented search strategy to quickly identify key sources of exposure limits. There are many sources of exposure limits for emergency response scenarios.^18,19 The search strategy is most effective when coupled with an exposure limit selection process. In general, selection processes use an embedded hierarchy of sources or use decision processes with predetermined decision criteria. An example of the hierarchical approach is the selection of Protective Action Criteria (PAC) in the CAMEO Suite. Alternatively, a customized decision criteria approach might include considerations such as relevance of the exposure limit to the scenario of interest and reliability of the limit, based on current science.²⁰ Although alternative strategies for exposure limit selection are valid, what is critical is to implement an approach that is systematic and documented and kept up to date. Such an approach could include the combining of a geographic information system with CAMEO and other systems to develop a Spill Management Information System.²¹

Most chemicals have no authoritative exposure limits. Thus, to use measured airborne exposure data to refine risk management and mitigation activities, an exposure limit or surrogate benchmark would need to be derived. Full derivation of a new value is not likely to be feasible within the context of the timing for most ongoing response activities. However, as an alternative to general recommendations, techniques to derive provisional or screening level exposure limits can be accomplished in hours, rather than days or months. One such technique is the concept of hazard banding or occupational exposure banding. The banding approach involves the aligning of hazard and toxicity data for predetermined critical endpoints against cut points or selection criteria that form hazard or potency bands for each endpoint. The resulting matrix of endpoints and potency bands is used to identify the exposure limit range expected for the chemical, based on its hazard data. The National Institute for Occupational Safety and Health (NIOSH) has proposed a strategy for deriving such bands for traditional occupational exposures, and a refinement of the general process for exposures relevant to emergency response workers might also be appropriate.^22,23 A derivative of the banding techniques is the assignment of potency bands based on distributions of known chemicals, rather than chemical-specific hazard data. By assuming an untested chemical is as potent as the most potent range of the distribution of chemicals, a default exposure limit can be derived; this general approach is called the Threshold of Toxicological Concern (TTC).^24,25 However, recommended TTC values have not been formally published for emergency response purposes. A third alternative is to use correlation analysis based on known relationships between key toxicological endpoints that are available for many chemicals (eg, lethal dose estimates) and exposure limits for acute or longer-term scenarios. This approach is incorporated in the derivation of some temporary emergency exposure limits (TEELs).²⁶

Recovery phase

During the recovery phase, the active release of the chemical is stabilized or controlled. Thus, the emergency situation evolves to more closely resemble the characteristics of traditional workplace exposures. This reflects that (1) exposures will be more predictable, (2) the duration of exposure has the potential to be more protracted for ongoing recovery, and (3) countervailing risk trade-offs related to victim rescue or environmental and community protection that must be weighed during the active response become less prominent, allowing a focus on worker protection. Under such circumstances, physical and health hazard information has a different influence on risk management and mitigation decisions than during initial and ongoing response phases. The application of workplace health and safety guidelines may become appropriate as responders are exposed to lower concentrations of hazardous materials for a longer duration, consistent with regulations and related worker health guidelines for cleanup of chemical releases.

A variety of hazard classification and characterization tools support workers during such incidents that move beyond the DOT and NFPA systems. HMIS is commonly used in workplaces and enhances the NFPA approach by explicitly considering and listing a symbol for the potential for chronic effects. However, the increased reliance on GHS is significant because it has international applications and has recently been incorporated in US OSHA’s HCS (29 CFR Part 1910.1200). The use of systems such as GHS provides an advantage in identifying with more specificity than NFPA the nature of the physical and health effects associated with the specific chemicals involved.

For extended periods of chemical handling during the recovery phase (eg, days to weeks), health benchmarks used to assess chemical risk are likely to reflect traditional OELs or their surrogates. As noted for the emergency exposure limit values, a process is needed for identification and selection of the most appropriate values. Where OELs are not available, they can be adapted from general population guidelines or alternative screening-level OELs can be derived. One important tool for filling the gap if OELs are not available is the hazard banding or occupational exposure band (OEB) approach, as described previously and in the Discussion.

Preparedness phase

Successful response and recovery from a chemical emergency are facilitated by effective emergency preparedness. The proper level of preparedness is achieved through continuous planning, organizing, training, equipping, exercising, evaluating, and taking corrective action (Figure 3).¹ Ongoing preparedness efforts among all those involved in emergency response activities will help ensure coordination during a crisis and will facilitate an efficient and effective emergency response.

Figure 3.

Stages of preparedness phase.

OSHA has published guidance and various requirements related to preparedness, including general requirements related to training, fire prevention, emergency action plans, medical services, and first aid, as well as additional requirements for workplaces that handle specific chemicals or blood borne pathogens. This information is outlined in the OSHA publication Principal Emergency Response and Preparedness Requirements and Guidance.²⁷ For example, the OSHA standard for Process Safety Management of highly hazardous chemicals (29 CFR Part 1910.119) covers processes that involve highly hazardous chemicals or flammable liquids and gases of a certain quantity or that involve the manufacture of pyrotechnics or explosives.²⁷ Another important OSHA regulation is the Hazardous Waste Operations and Emergency Response standard (29 CFR Part 1910.120), which details requirements related to various cleanup operations when employees have been exposed to hazardous waste. OSHA also has additional standards related to specific substances and situations.

Other government entities have regulatory requirements and guidance related to preparedness. For instance, the Federal Railroad Administration has published a guide to creating an emergency preparedness plan for passenger railroads,²⁸ as required by 49 CFR 239.101. The NFPA has standards that address response planning, to be used by responder personnel in the case of a fire or other emergency event.²⁹ The Environmental Protection Agency (EPA) also provides preparedness information via the Emergency Planning and Community Right-to-Know Act (EPCRA), which aids state, tribal, and local governments in the development of response plans and the coordination of response activities.³⁰ Such information supports the roles of Local Emergency Planning Committees in tracking and management of hazardous chemical inventories. The NIMS approach also includes emphasis on such local coordination in effective response.

As with the other phases of emergency response, several key information inputs are necessary for successful preparedness planning. The conduct of evaluations of response plans and preparedness planning provides an opportunity to ensure that compilations of chemical hazard information resources are up to date. Response evaluations from previous incidents are important input for the emergency preparedness phase. Certain types of chemical emergencies must be reported to the Pipeline and Hazardous Materials Safety Administration, as required by HMR (49 CFR Parts 171–180). The US DOT provides guidance on preparing hazardous materials incident reports for this purpose. Information from previous incidents is used to design response plans for potential future incidents.

Case studies

The search for, evaluation of, and proper utilization of appropriate information resources during a chemical hazard response incident are essential in the successful management of the incident. The following case studies (Tables 2 and 3) demonstrate the application of these concepts as discussed in this article by noting where management of the incident is aligned with the information resources framework, highlighting deviations from the framework, and suggesting possible improvements that could have potentially improved the outcomes.

Table 2.

Case study #1

Case study #131
Incident description	• Health outcomes: Five workers died and three were severely injured in an explosion and fire at a polyvinyl chloride (PVC) manufacturing facility.  • Possible cause: An operator cleaning a reactor likely opened the bottom valve on an operating reactor, releasing highly flammable contents. After noticing vinyl chloride monomer (VCM) concentrations above the OSHA permissible exposure limit (PEL) (1 part per million, or ppm), the supervisor and two operators attempted to control the release.  • Timeline: The interval between the initial release and the first explosion was approximately 5 minutes. The facility burned for 2 days, producing smoke containing VCM that drifted over the local community.
Initial response phase	Scenario characterization  • VCM release identified Key information inputs  • Facility response plan guidance to don PPE, evacuate, initiate external emergency contact process  • ERG Guide 116, Gases: flammable (unstable)—evacuate 1 mile in all directions Mitigation actions  • Two operators attempted to manage release, not following pre-plan guidance to don PPE and evacuate.  • Emergency personnel evacuated residents, consistent with ERG 116.
Ongoing response phase	Update of scenario characterization  • Fire and explosion involved VCM vapor and PVC resins, and the smoke contained dioxin. Key information inputs  • Confirmatory air sampling and vapor plume modeling, that is, use of CAMEO suite of modeling tools  • Identification of appropriate levels of concern (LOCs)   ○ Physical hazards: Release is already on fire. Protective distances are developed on the basis of NFPA guidance for active fire. Evaluate potential for further explosion. In the active zone, the primary determination of mitigation actions is driven by flammability and explosion hazards.   ○ Health hazards: Implement protective-action criteria decision process, that is, use of acute exposure guideline level or ERPG or consideration of nonemergency guide values. For VCM, the default protective action criterion (PAC) Level 1 is 250 ppm in CAMEO. For dioxin, the PAC-1 is 0.00003 μg/m3. Mitigation action  • Consider updating evacuation distances identified in initial response.
Recovery phase	Update of scenario characterization  • After 2 days, fire is extinguished and active release has been mitigated.  • Primary concern is residual contamination on- and off-site. Key information inputs  • Additional sampling, including air, water, and soil  • Identification and selection of appropriate human health exposure limits   ○ Physical hazards: No longer a primary concern for this scenario, unless residual flammable liquids persist   ○ Health hazards: Control exposures according to OELs (OSHA PEL and ACGIH TLV = 1 ppm for vinyl chloride) for cleanup personnel. Use limits geared for general population, such as intermediate minimal risk levels (MRLs) (0.03 ppm for vinyl chloride) for community exposure. Vinyl chloride has acute and chronic effects such as cancer that need to be considered, on the basis of concentration and duration of exposure. Some off-site soil tests indicated dioxin was slightly above suggested background level (1.0 part per trillion, or ppt), but none were at or above the action level (1.0 part per billion, or ppb), which still is being monitored. Mitigation actions  • Apply hierarchy of controls (design tasks to reduce exposure and select appropriate PPE); implement decontamination procedures and medical surveillance plan.  • Verify community safety and resume normal activities.
Preparedness phase	Response evaluation  • A US Chemical Safety Board investigation was conducted: facility emergency procedures were not clear and a suitable emergency drill had not been conducted for more than 10 years. Development/updating of response plan  • Since primary chemicals of concern are known, the response plan should include pre-modeling of plumes based on potential emergency conditions and selection of guide values for each response phase.  • A full response pre-plan would have ensured that scenario-specific information was available immediately for the emergency response team.

Table 3.

Case study #2

Case study #232
Incident description	• Health outcomes: Three workers died and several others were injured in chemical releases, explosion, and fire at a facility that manufactures methane sulfonyl chloride and methane sulfonic acid.  • Possible cause: A pipe connected to the unloading line of a tank car fractured and separated, leading to methyl mercaptan release. The methyl mercaptan ignited and the fire damaged an adjacent tank car, causing the release of chlorine. Erosion-corrosion to the pipe was one cause of the incident. However, the direct cause is unknown.  • Timeline: The interval between the initial release and the explosion was approximately 24 minutes, and the facility burned for about 5.5 hours. The released chemicals and toxic combustion products drifted over the surrounding communities. About 2,000 residents were evacuated for approximately 10 hours.
Initial response phase	Scenario characterization  • Methyl mercaptan and chlorine release and fire identified Key information inputs  • Facility response plan guidance was followed to secure process, don PPE, try to control the incident, and start the initial external emergency contact process.  • For methyl mercaptan, ERG Guide 117, gases—toxic—flammable (extreme hazard), and Table 1—evacuate 1 mile in all directions, then protect persons downwind during night; the distance is 3,200 m.  • For chlorine, ERG Guide 124, gases—toxic and/or corrosive—oxidizing, and Tables 1 and 3—protect persons downwind during night; the distance is 7,100 m. Mitigation actions  • Process was secured in accordance with company emergency response procedures. Water was sprayed toward the tank car to knock down the fumes from tank.  • Other actions taken included wearing self-contained breathing apparatus (SCBA) during rescue.  • Emergency personnel evacuated residents on the basis of ERG recommendations.
Ongoing response phase	Update of scenario characterization  • The released chemicals and toxic combustion products drifted over the surrounding communities. Key information inputs  • Confirmatory air sampling and vapor plume modeling, that is, use of CAMEO suite of modeling tools  • Identification of appropriate LOCs   ○ Physical hazards: Release is already on fire. Protective distances were developed on the basis of NFPA guidance for active fire. Evaluate potential for further explosion. In the active zone, the primary determination of mitigation actions was driven by flammability and explosion hazards.   ○ Health hazards: Implement protective action criteria decision process, that is, use of acute exposure guideline level, ERPG, or consideration of nonemergency guide values. For methyl mercaptan, the PAC Level 1 is 0.005 ppm in CAMEO. For chlorine, the PAC Level 1 is 0.5 ppm in CAMEO. Mitigation action One hour after the fire, the Riverview fire chief advised the Grosse Ile Police Department to have the resident’s shelter in place. However, 20 minutes later, after re-evaluating the situation, the Riverview fire chief requested the evacuation of residents of parts of Riverview, Trenton, Grosse Ile, and Wyandotte.
Recovery phase	Update of scenario characterization  • After 5.5 hours, fire was extinguished. After 1.5 days, Fire Department active units were released. Only one engine and two firefighters were on-site. Primary concern was residual contamination on- and off-site.  • Fire Department personnel were on-site and monitoring the accident site for residue of hazardous materials up to 3 days after the incident. Key information inputs  • Additional sampling, including air, water, and soil  • Identification and selection of appropriate human health exposure limits   ○ Physical hazards: No longer a primary concern for this scenario, unless residual flammable gas/liquid persist   ○ Health hazards: Control exposures according to OELs (for methyl mercaptan and chlorine, OSHA PEL and ACGIH TLV are both 0.5 ppm) for cleanup personnel. Use limits geared for general population, such as intermediate MRLs (0.002 ppm for chlorine) or Texas Commission of Environmental Quality’s Toxicology Division Effects Screening Level (ESL) (0.03 ppb for methyl mercaptan) for community exposure.
Recovery phase	Mitigation actions: Appropriate actions include applying hierarchy of controls during cleanup (design tasks to reduce exposure and select appropriate PPE), implement decontamination procedures and medical surveillance plan, and verify community safety on the basis of exposure guidelines.
Preparedness phase	Conduct response evaluation  • A National Transportation Safety Board investigation was conducted. Only one of the six methyl mer- captan sensors worked. Explosion-proof emergency switches were not designed to close the valves on the methyl mercaptan tank cars. The methyl mercaptan tank car was not equipped with a remote or automatic mechanism to stop the flow of material during an emergency.  • On March 1, 2000, ATOFINA executed an emergency plan for the facility. Copies of the emergency plan were sent to fire departments of the surrounding communities, and periodic tours and training were provided.  • The communication between the plant nurse and local hospitals focused only on the treatment of employees injured because of work duty. Development/updating of response plan  • The plant gave presentations to the hospital to promote knowledge of chemical exposure, basic toxicology, decontamination, and basic hazardous materials. A hazardous materials room, where victims of hazardous materials accidents could be isolated, also was recommended.  • The plant had made changes to its procedures and equipment to address the identified problems. Since the accident, ATOFINA has implemented procedures that require operators to wear a SCBA when making cargo transfer connections to methyl mercaptan tank cars. ATOFINA has also changed its leak-testing procedures and now tests the tank car unloading apparatus by pressurizing it with nitrogen gas and using a soap solution to detect leaks before the unloading valve on the tank car is opened. In addition, all workers in the area of tank cars containing poison gases must now carry an escape hood with an emergency air supply.

Discussion

This article describes the information resources used in chemical emergency management and operations and how the utility of these resources evolves from the initial response phase to recovery to event close out. Emergency incidents vary greatly, and specialized risk management mitigation actions (eg, PPE and cleanup measures) are often required. Information is needed to make decisions in the response to chemical releases, and the resources should identify all physical and health hazards and risk management and mitigation procedures applicable to the event.

Because the information flow is complex, a systematic information management approach is needed that assures timely and accurate information is available to support risk management and mitigation strategies. The framework approach suggested in this article includes an assessment of data needs, an evaluation of key resources, and an approach to keep the information resources current. Such a system also needs to keep pace with the trends in information access and the likelihood for growing access to information. For example, several trends to include in a strategy are:

• More data access results in the need for improved data screening, filtering, and mining tools.

• Variability in user communities suggests tools should accommodate different end users, including techniques for improved data queries and data organization.

• The confusing landscape of information requires approaches to support decision making, including tools to increase utility of the information via pre-worked information hierarchies (eg, the US Department of Energy’s current data set of PAC, for chemicals with acute exposure guideline levels [AEGLs], Emergency Response Planning Guidelines (ERPGs), and/or TEELs³³) and decision logic that identifies hazards or select key information (eg, the CHEMM-Intelligent Syndromes Tool³⁴ and/or the Dermal Exposure Risk Management and Logic for Emergency Preparedness and Response (DERMaL eToolkit³⁵).

• Information access in emergency management and operations has a significant component of outreach (to inform users of data resource availability) and education (to ensure users can optimize their application of each information resource).

A second important consideration is the ability to fill gaps in needed data. There are over 89 million chemicals in the Chemical Abstracts Services Registry. An additional 15,000 new substances are added each day.³⁶ Most of these chemicals are not used actively in commerce. Although the exact number of chemicals in commerce is unknown, 143,835 chemical substances were pre-registered under the pre-registration requirement of the chemicals regulation of the European Union—the Registration, Evaluation, Authorization, and Restriction of Chemicals. According to the United Nations Environment Programme,³⁷ this is a reasonable guide to the approximate number of chemicals in commerce globally. However, very few chemicals have been assessed and assigned authoritative occupational or emergency exposure limits, such as OSHA PELs, NIOSH recommended exposure limits, American Industrial Hygiene Association workplace environmental exposure levels®, American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values® (TLVs), NIOSH immediately dangerous to life or health concentrations, and AEGLs. The introduction of new chemicals into commerce continues to outpace the development of exposure guidelines for these chemicals. With such a lack of guidance regarding acceptable exposure limits, a systematic approach is needed to obtain accurate chemical-specific information to address the myriad chemicals that could potentially be involved during an emergency response. This is of paramount importance not only for workplace exposures but also for first responders.

Furthermore, the systematic approach should account for the decision process being dynamic and evolving as the incident moves through the initial response, ongoing response, and recovery phases. One tool we have introduced in this article that is not traditionally applied in the EMR community is the NIOSH Occupational Exposure Banding process. The NIOSH process can be used to evaluate chemicals that have not been assigned authoritative OELs, in order to provide an estimated range of exposure levels. The output of this process is an OEB, which represents a range of inhalation-based concentrations expected to be protective of worker health. OEBs complement OELs and can be incorporated into a workplace health and safety program. While this approach is often used in workplace settings, it can also be applied as part of a risk management framework for first responders. The OEB concept supports response phases in the following ways:

• Assisting with planning via the ability to pre-populate levels of concern for many diverse scenarios amenable to chemicals with limited data.

• Assisting with the initial, ongoing response, and recovery phases, including accessibility for rapid development (hours, not days).

• Differentiating between temporal scenarios (acute vs chronic) and likely effects of concern.

The availability of numerous resources necessitates the integration of data to inform risk management and mitigation decisions. Given that many chemicals pose physical and health hazards, an effective risk management and mitigation strategy integrates both physical and health risks to support decision making during ongoing response. Numerous considerations support decisions with regard to physical and health risks. One important aspect of integration is the interplay between flammability, health, and reactivity, which is pertinent to risk management and mitigation strategies. These hazards are considered together to some extent in guidance such as the ERG. The following are several important considerations:

• Accommodating concern for all hazards present or requiring removal of one hazard before entering, where a single risk mitigation approach does not address all hazards,

• Applying a decision approach where risk mitigation actions are in conflict, to minimize overall impacts on health,

• Ensuring that the level of hazard is consistently weighed in the decision process, such as developing an approach to address a response for an event involving the spill of a chemical that has NFPA codes 4, 4, 4 vs 4, 2, and 1.

This manuscript describes several aspects of an information management strategy and the application of a framework approach to support identifying and using information during different aspects of EMR. Targeted research would provide an additional basis to develop new tools and decision making resources to facilitate the application of a systematic approach. For example, in developing the DERMaL e-Tool, NIOSH collected feedback via formal expert elicitation methods to improve the identification and weighting of relevant resources into a web-based tool that is now housed on the CHEMM resource via the National Library of Medicine. A similar data collection approach using focus groups, targeted surveys, or other mechanisms could serve as the basis of an EMR tool that covers broader needs in chemical risk management and mitigation as highlighted in this article.

The application of a systematic approach was described in this manuscript in the context of identifying exposure limits appropriate to a scenario and EMR phase or activity. Hierarchies for OEL and emergency response limits do exist and can be adopted and deployed during an EMR activity. However, the absence of published limits for most chemicals has been a significant driver for development of the occupational exposure banding concept. A banding approach has been developed by NIOSH that addresses inhalation route exposures for workers. Additional research is needed to develop and validate a similar scheme for providing inhalation exposure limit guidance for acute EMR phases as well as addressing dermal route exposures. New methods in these areas would increase the availability of quantitative and chemical-specific exposure limit guidance.

Conclusion

The framework presented in this manuscript outlines a strategic and efficient way to rapidly identify appropriate emergency management resources at each stage of a chemical incident. The framework emphasizes the need for efficient integration different information types as an incident evolves, such that the mitigations actions are continuously improving. Paper-based and downloaded content resources (eg, the ERG), electronic information sources and software tools (eg, WISER and the CAMEO suite), and telephone information services (eg, CHEMTREC and CDC-INFO) can each be used during a chemical incident. An understanding of when to consult each type of resource improves the efficiency of the response. In summary, the success of emergency management operations is greatly dependent upon the assessment of evolving conditions and concerns and a systematic approach to searching and accessing relevant and informative resources that can be applied in a timely manner.