bronchorrhea, and bronchospasm In individual cases, clinical differentiation may be difficult Further, features of poisoning may be partially obscured by trauma when chemicals are disseminated explosively; significant numbers of atraumatic casualties will be more easily recognized as chemical in nature Toxidromes—constellations of signs and symptoms suggestive of a specific class of poison—can be very useful in narrowing differential diagnoses, although patients may exhibit incomplete or atypical signs and symptoms such as with the cholinergic toxidrome (for nerve agents) Just as with biologic agents, it is convenient to categorize chemical weapons exposures as causing predominantly neurologic, respiratory, or dermatologic syndromes that can help the practitioner in identifying an offending agent ( Fig 132.3 ) There are several resources that will be helpful to ED physicians, including internet-accessible and downloadable algorithms and related tools (e.g., the CHEMM Intelligent Syndromes Tool, or CHEMM-IST, at http://chemm.nlm.nih.gov/chemmist.htm ), local medical toxicologists, regional poison control centers (1-800-222-1222), and public health authorities Triage Considerations: General Management, Decontamination, and Personal Protection Ideally, the general management of chemically contaminated victims begins with prehospital providers at the scene (“hot zone”), garbed in appropriate personal protective equipment (PPE), providing extrication, triage, medical stabilization, and immediate or spot decontamination such as the prompt removal of any suspicious liquid from a casualty Patients are then transferred to the “warm zone,” a receiving area for chemical casualties ( Fig 132.4 ) The Occupational Safety & Health Administration (OSHA) designates sites such as a hospital corridor as the “warm zone.” The warm zone may also be located outside as with a tent on hospital grounds ( Fig 132.5 ) The warm zone is separated from the “cold zone” (beginning no later than the entrance to the ED) by a “hot line,” or liquid-control zone, beyond which no liquid contamination is permitted to pass That is, patients should be thoroughly decontaminated before entering the cold zone Many patients, especially those who are self-referred, may arrive for ED care having not been decontaminated at the scene Unstable and contaminated patients present a particular challenge For such patients, it is useful to conceptualize the phases of emergent resuscitation in the warm zone as the ABCDDs: airway, breathing, circulation, immediate or spot decontamination, and drugs (including anticonvulsants and antidotes) It is often mistakenly assumed that