Medical Aspects of Chemical Warfare (2008) - The Black Vault

Medical Aspects of Chemical Warfareas the American Southwest may be very comfortablein protective clothing during winter but unable totolerate the same level of protection in the heat ofsummer. Therefore, it is very important to observework–rest cycles.Preplacement examination has two major functions:(1) to determine an individual’s fitness for duty, includinghis or her ability to work while wearing PPE;and (2) to provide baseline medical surveillance forcomparison with future medical data. 10 Chemical agentworkers must be evaluated to ensure that they are notpredisposed to physical, mental, or emotional impairmentthat may result in an increased vulnerability tochemical warfare agent exposure. This examination isperformed at no cost to the applicant. Abnormalitiesidentified during the course of the preplacement examination,however, need to be followed up by the applicant,at his or her expense, with a private physician.The first step in acquiring necessary informationfrom a prospective worker is an occupational andmedical history questionnaire. The medical officeris required to conduct a thorough review to identifypast illnesses and diseases that may prevent satisfactoryjob performance. It is particularly important toinquire about skin, lung, cardiovascular, and psychiatricdisease to evaluate the ability of an individual towork in protective ensemble. Questions concerningshortness of breath or labored breathing on exertion,asthma or other respiratory symptoms, chest pain, highblood pressure, and heat intolerance provide helpfulinformation, as do questions about hypersensitivityto rubber products and cold-induced bronchospasms.The medical officer should also take a brief psychiatrichistory to determine the individual’s ability to beencapsulated in PPE; questions about panic attacks,syncopal episodes, or hyperventilation can supplyvaluable information.A potential employee’s physical examination shouldfollow the medical history questionnaire. It should becomprehensive and focus on the skin and the cardiovascular,pulmonary, and musculoskeletal systems.Obesity, lack of physical strength, and poor muscletone are indicators of increased susceptibility to heatinjury, a condition that is amplified by working inchemical protective clothing. Factors that restrict thewearing of protective clothing include (a) the inabilityto obtain a seal with the protective mask, (b) an allergyto protective clothing and equipment, (c) any medicalcondition that precludes correct wear of protectiveclothing, and (d) poor visual acuity that requires theuse of glasses unless mask optical inserts are used.Facial hair, scarring, dentures, and arthritic hands orfingers can affect a worker’s ability to wear a respiratorand protective clothing. Acne scarring and pseudofolliculitisbarbae are common facial skin conditions thatmay interfere with proper mask seal. Mask fit testingshould be used to augment fitness determination inthese cases.Baseline data acquired during the preplacementscreening can be used following an exposure event todetermine the extent of the exposure. This data canalso be used to verify the engineering controls in effect,and it may be used to determine if the worker hasbeen adversely affected by exposure. Red blood cellcholinesterase (RBC-ChE) baseline levels are essentialfor workers assigned to areas in which nerve agent munitionsare stored. Workers are categorized by the areathey are assigned to and how frequently they are in achemical environment, and the frequency of follow-upexaminations is determined by this category. Thesecategories are in a state of flux; the current regulatoryguidance is discussed in the following section. As ofthe date of this writing, RBC-ChE baseline levels mustbe determined every 3 years by a two-draw series, withthe draws taking place within 10 days of each other.This test may be performed at the installation level or atthe cholinesterase reference laboratory of the US ArmyCenter for Health Promotion and Preventive Medicine.This reference laboratory serves as a central repositoryof RBC-ChE baseline values and provides enhancedquality control and record management. RBC-ChEmeasurement is necessary throughout a worker’semployment to monitor for nerve agent exposure.The surety officer, safety officer, and IMA are jointlyresponsible for determining who will be monitoredand how often. Certifying officials and other supervisorsare responsible for supplying information aboutthe worker’s duties, and an accurate job descriptionis essential.Periodic Medical ExaminationsPeriodic medical examinations should be used inconjunction with preplacement screening examinations.10 Comparing the data obtained through periodicmonitoring with the baseline data is essentialfor identifying early signs of occupationally induceddiseases. The periodic medical examination is intendedto identify any conditions for which early interventioncan be beneficial.The frequency and extent of the periodic medicalexamination should be determined by the toxicity ofthe potential or actual exposures, frequency and durationof the contact, and the information obtained in thepreplacement history and physical examination. Thedata obtained from these periodic examinations canguide the future frequency of physical examinationsor tests. Data consistently within acceptable limits for600