We thank the Edmonton Fire-fighters’ Union for their interest and generous support of the development of this chapter. The “Edmonton Sun” and the “Edmonton Journal” graciously allowed their news photographs to be used in the articles on firefighting. Ms. Beverly Cann of the Manitoba Federation of Labour Occupational Health Centre contributed invaluable advice on the article on paramedical personnel and ambulance attendants.

Fire-brigade personnel may be engaged on a full-time, part-time, paid-on-call or unpaid, volunteer basis—or on a combination of these systems. The type of organization employed will, in most cases, depend on the size of the community, the value of the property to be protected, the types of fire risk and the number of calls typically answered. Cities of any appreciable size require regular fire brigades with full crews on duty equipped with the appropriate apparatus.

Smaller communities, residential districts and rural areas having few fire calls usually depend upon volunteer or paid-on-call fire-fighters for either full staffing of their firefighting apparatus or to assist a skeleton force of full-time regulars.

Although there are a great many efficient, well equipped volunteer fire departments, full-time, paid fire departments are essential in larger communities. A call or volunteer organization does not lend itself as readily to the continuous fire-prevention inspection work that is an essential activity of modern fire departments. Using volunteer and call systems, frequent alarms may call out workers who hold other jobs, causing a loss of time with seldom any direct benefit to employers. Where full-time fire-fighters are not employed, the volunteers must come to a central fire hall before response can be made to a call, causing a delay. Where there are only a few regulars, a supplementary group of well-trained call or volunteer fire-fighters should be provided. There should be a reserve arrangement that make assistance available for the response of neighbouring departments on a mutual-aid basis.

Firefighting is a highly unusual occupation, in that it is perceived of as dirty and dangerous but is indispensable and even prestigious. Fire-fighters enjoy public admiration for the essential work that they do. They are well aware of the hazards. Their work involves intermittent periods of exposure to extreme physical and psychological stress on the job. Fire-fighters are also exposed to serious chemical and physical hazards, to a degree unusual in the modern workforce.

Hazards

Occupational hazards experienced by fire-fighters may be categorized as physical (mostly unsafe conditions, thermal stress and ergonomic stress), chemical and psychological. The level of exposure to hazards that may be experienced by a fire-fighter in a given fire depends on what is burning, the combustion characteristics of the fire, the structure that is on fire, the presence of non-fuel chemicals, the measures taken to control the fire, the presence of victims that require rescue and the position or line of duty held by the fire-fighter while fighting the fire. The hazards and levels of exposure experienced by the first fire-fighter to enter a burning building are also different from those of the fire-fighters who enter later or who clean up after the flames are extinguished. There is usually rotation among the active firefighting jobs in each team or platoon, and a regular transfer of personnel between fire halls. Fire-fighters may also have special rank and duties. Captains accompany and direct the crews but are still actively involved in fighting the fire on site. Fire chiefs are the heads of the fire service and are called out only in the worst fires. Individual fire-fighters may still experience unusual exposures in particular incidents, of course.

Physical hazards

There are many physical dangers in firefighting that can lead to serious physical injury. Walls, ceilings and floors can collapse abruptly, trapping fire-fighters. Flashovers are explosive eruptions of flame in a confined space that occur as a result of the sudden ignition of flammable gas products driven out of burning or hot materials and combined with superheated air. Fire situations that lead to flashovers may engulf the fire-fighter or cut off escape routes. The extent and number of injuries can be minimized by intensive training, job experience, competency and good physical fitness. However, the nature of the job is such that fire-fighters may be placed in dangerous situations by miscalculation, circumstance or during rescues.

Some fire departments have compiled computerized databases on structures, materials and potential hazards likely to be encountered in the district. Quick access to these databases assists the crew in responding to known hazards and anticipating possibly dangerous situations.

Thermal hazards

Heat stress during firefighting may come from hot air, radiant heat, contact with hot surfaces or endogenous heat that is produced by the body during exercise but which cannot be cooled during the fire. Heat stress is compounded in firefighting by the insulating properties of the protective clothing and by physical exertion, which result in heat production within the body. Heat may result in local injury in the form of burns or generalized heat stress, with the risk of dehydration, heat stroke and cardiovascular collapse.

Hot air by itself is not usually a great hazard to the fire-fighter. Dry air does not have much capacity to retain heat. Steam or hot, wet air can cause serious burns because much more heat energy can be stored in water vapour than in dry air. Fortunately, steam burns are not common.

Radiant heat is often intense in a fire situation. Burns may occur from radiant heat alone. Fire-fighters may also show skin changes characteristic of prolonged exposure to heat.

Chemical hazards

Over 50% of fire-related fatalities are the result of exposure to smoke rather than burns. One of the major contributing factors to mortality and morbidity in fires is hypoxia because of oxygen depletion in the affected atmosphere, leading to loss of physical performance, confusion and inability to escape. The constituents of smoke, singly and in combination, are also toxic. Figure 1 shows a fire-fighter using self-contained breathing apparatus (SCBA) rescuing an unprotected fire-fighter who was trapped in a very smoky fire in a tire warehouse. (The fire-fighter being rescued ran out of air, took off his SCBA to breathe as best he could, and was fortunate enough to be rescued before it was too late.)

Figure 1.  Fire-fighter rescuing another fire-fighter who was trapped in the toxic smoke from a fire in a tire warehouse.

All smoke, including that from simple wood fires, is hazardous and potentially lethal with concentrated inhalation. Smoke is a variable combination of compounds. The toxicity of smoke depends primarily on the fuel, the heat of the fire and whether or how much oxygen is available for combustion. Fire-fighters on the scene of a fire are frequently exposed to carbon monoxide, hydrogen cyanide, nitrogen dioxide, sulphur dioxide, hydrogen chloride, aldehydes and organic compounds such as benzene. Different gas combinations present different degrees of hazard. Only carbon monoxide and hydrogen cyanide are commonly produced in lethal concentrations in building fires.

Carbon monoxide is the most common, characteristic and serious acute hazard of firefighting. Carboxyhaemoglobin accumulates rapidly in the blood with duration of exposure, as a result of the affinity of carbon monoxide for haemoglobin. High levels of carboxyhaemoglobin may result, particularly when heavy exertion increases minute ventilation and therefore delivery to the lung during unprotected firefighting. There is no apparent correlation between the intensity of smoke and the amount of carbon monoxide in the air. Fire-fighters should particularly avoid cigarette smoking during the clean-up phase, when burning material is smouldering and therefore burning incompletely, as this adds to the already elevated levels of carbon monoxide in the blood. Hydrogen cyanide is formed from the lower temperature combustion of nitrogen-rich materials, including natural fibres such as wool and silk, as well as common synthetics such as polyurethane and polyacrylonitrile.

Light-molecular-weight hydrocarbons, aldehydes (such as formaldehyde) and organic acids may be formed when hydrocarbon fuels burn at lower temperatures. The oxides of nitrogen are also formed in quantity when temperatures are high, as a consequence of the oxidation of atmospheric nitrogen, and in lower temperature fires where the fuel contains significant nitrogen. When the fuel contains chlorine, hydrogen chloride is formed. Polymeric plastic materials pose particular hazards. These synthetic materials were introduced into building construction and furnishings in the 1950s and thereafter. They combust into particularly hazardous products. Acrolein, formaldehyde and volatile fatty acids are common in smouldering fires of several polymers, including polyethylene and natural cellulose. Cyanide levels increase with temperature when polyurethane or polyacrylonitriles are burned; acrylonitrile, acetonitrile pyridine and benzonitrile occur in quantity above 800 but below 1,000 °C. Polyvinyl chloride has been proposed as a desirable polymer for furnishings because of its self-extinguishing characteristics due to the high chlorine content. Unfortunately, the material produces large quantities of hydrochloric acid and, sometimes, dioxins when fires are prolonged.

Synthetic materials are most dangerous during smouldering conditions, not in conditions of high heat. Concrete retains heat very efficiently and may act as a “sponge” for trapped gases that are then released from the porous material, releasing hydrogen chloride or other toxic fumes long after a fire has been extinguished.

Psychological hazards

A fire-fighter enters a situation that others are fleeing, walking into immediate personal danger greater than in almost any other civilian occupation. There is much that can go wrong in any fire, and the course of a serious fire is often unpredictable. Besides personal security, the fire-fighter must be concerned with the safety of others threatened by the fire. Rescuing victims is an especially stressful activity.

The professional life of a fire-fighter is more than an endless round of anxious waiting punctuated by stressful crises, however. Fire-fighters enjoy the many positive aspects of their work. Few occupations are so respected by the community. Job security is largely assured in urban fire departments once a fire-fighter is hired, and the pay usually compares well with other jobs. Fire-fighters also enjoy a strong sense of team membership and group bonding. These positive aspects of the job offset the stressful aspects and tend to protect the fire-fighter against the emotional consequences of repeated stress.

At the sound of an alarm, a fire-fighter experiences a degree of immediate anxiety because of the inherent unpredictability of the situation he or she is about to encounter. The psychological stress experienced at this moment is as great and perhaps greater than any of the stresses that follow during the course of responding to an alarm. Physiological and biochemical indicators of stress have shown that fire-fighters on duty have sustained psychological stress that reflects subjectively perceived patterns of psychological stress and activity levels at the station.

Health Risks

The acute hazards of firefighting include trauma, thermal injury and smoke inhalation. The chronic health effects that follow recurrent exposure have not been so clear until recently. This uncertainty has led to a patchwork of employment and workers’ compensation board policies. The occupational risks of fire-fighters have received a great deal of attention because of their known exposure to toxic agents. A large body of literature has developed on the mortality experience of fire-fighters. This literature has grown with the addition of several substantial studies in recent years, and a sufficient database is now available to describe certain patterns in the literature.

The critical compensation issue is whether a general presumption of risk can be made for all fire-fighters. This means that one must decide whether all fire-fighters can be assumed to have an elevated risk of a particular disease or injury because of their occupation. To satisfy the usual compensation standard of proof that the occupational cause must be more likely than not responsible for the outcome (giving the benefit of the doubt to the claimant), a general presumption of risk requires a demonstration that the risk associated with occupation must be at least as great as the risk in the general population. This can be demonstrated if the usual measure of risk in epidemiological studies is at least double the expected risk, making allowances for uncertainty in the estimate. Arguments against presumption in the specific, individual case under consideration are called “rebuttal criteria”, because they can be used to question, or rebut, the application of the presumption in an individual case.

There are a number of unusual epidemiological characteristics that influence the interpretation of studies of fire-fighters and their occupational mortality and morbidity. Fire-fighters do not show a strong “healthy worker effect” in most cohort mortality studies. This may suggest an excess mortality from some causes compared to the rest of the healthy, fit workforce. There are two types of healthy worker effect that may conceal excess mortality. One healthy worker effect operates at the time of hire, when new workers are screened for firefighting duty. Because of the strenuous fitness requirements for duty, this effect is very strong and might be expected to have an effect of reducing mortality from cardiovascular disease, especially in the early years following hire, when few deaths would be expected anyway. The second healthy worker effect occurs when workers become unfit following employment due to obvious or subclinical illness and are reassigned to other duties or are lost to follow-up. Their relative high contribution to total risk is lost by undercount. The magnitude of this effect is not known but there is a strong evidence that this effect occurs among fire-fighters. This effect would not be apparent for cancer because, unlike cardiovascular disease, the risk of cancer has little to do with fitness at the time of hire.

Lung Cancer

Lung cancer has been the most difficult cancer site to evaluate in epidemiological studies of fire-fighters. A major issue is whether the large-scale introduction of synthetic polymers into building materials and furnishings after about 1950 increased the risk of cancer among fire-fighters because of exposure to the combustion products. Despite the obvious exposure to carcinogens inhaled in smoke, it has been difficult to document an excess in mortality from lung cancer big enough and consistent enough to be compatible with occupational exposure.

There is evidence that work as a fire-fighter contributes to risk of lung cancer. This is seen mostly among fire-fighters who had the highest exposure and who worked the longest time. The added risk may be superimposed on a greater risk from smoking.

Evidence for an association between firefighting and lung cancer suggests that the association is weak and does not attain the attributable risk required to conclude that a given association is “more likely than not” due to occupation. Certain cases with unusual characteristics may warrant this conclusion, such as cancer in a relatively young non-smoking fire-fighter.

Cancer at Other Sites

Other cancer sites have been shown recently to be more consistently associated with firefighting than lung cancer.

The evidence is strong for an association with genito-urinary cancers, including kidney, ureter and bladder. Except for bladder, these are rather uncommon cancers, and the risk among fire-fighters appears to be high, close to or in excess of a doubled relative risk. One could therefore consider any such cancer to be work-related in a fire-fighter unless there is a convincing reason to suspect otherwise. Among the reasons one might doubt (or rebut) the conclusion in an individual case would be heavy cigarette smoking, prior exposure to occupational carcinogens, schistosomiasis (a parasitic infection—this applies to bladder only), analgesic abuse, cancer chemotherapy and urologic conditions that result in stasis and prolonged residence time of urine in the urinary tract. These are all logical rebuttal criteria.

Cancer of the brain and central nervous system has shown highly variable findings in the extant literature, but this is not surprising since the numbers of cases in all reports are relatively small. It is unlikely that this association will be clarified any time soon. It is therefore reasonable to accept a presumption of risk for fire-fighters on the basis of current evidence.

The increased relative risks for lymphatic and haematopoietic cancers appear to be unusually high. However, the small numbers of these relatively rare cancers make it difficult to evaluate the significance of the association in these studies. Because they are individually rare, epidemiologists group them together in order to make statistical generalizations. The interpretation is even more difficult because grouping these very different cancers together makes little sense medically.

Heart Disease

There is no conclusive evidence for an increased risk of death overall from heart disease. Although a single large study has shown an excess of 11%, and a smaller study confined to ischemic heart disease suggested a significant excess of 52%, most studies cannot conclude that there is a consistently increased population risk. Even if the higher estimates are correct, the relative risk estimates still fall far short of what would be required to make a presumption of risk in the individual case.

There is some evidence, primarily from clinical studies, to suggest a risk of sudden cardiac decompensation and risk of a heart attack with sudden maximal exertion and following exposure to carbon monoxide. This does not seem to translate into an excess risk of fatal heart attacks later in life, but if a fire-fighter did have a heart attack during or within a day after a fire it would be reasonable to call it work-related. Each case must therefore be interpreted with a knowledge of individual characteristics, but the evidence does not suggest a generally elevated risk for all fire-fighters.

Aortic Aneurysm

Few studies have accumulated sufficient deaths among fire-fighters from this cause to achieve statistical significance. Although one study conducted in Toronto in 1993 suggests an association with work as a fire-fighter, it should be considered an unproven hypothesis at present. Should it be ultimately confirmed, the magnitude of risk suggests that it would merit acceptance on a schedule of occupational diseases. Rebuttal criteria would logically include severe atherosclerosis, connective tissue disease and associated vasculitis and a history of thoracic trauma.

Lung Disease

Unusual exposures, such as intense exposure to the fumes of burning plastics, can certainly cause severe lung toxicity and even permanent disability. Ordinary firefighting may be associated with short-term changes similar to asthma, resolving over days. This does not appear to result in an increased lifetime risk of dying from chronic lung disease unless there has been an unusually intense exposure (the risk of dying from the consequences of smoke inhalation) or smoke with unusual characteristics (particularly involving burning polyvinyl chloride (PVC)).

Chronic obstructive pulmonary disease has been extensively studied among fire-fighters. The evidence does not support an association with firefighting, and therefore there can be no presumption. An exception may be in rare cases when a chronic lung disease follows an unusual or severe acute exposure and there is a compatible history of medical complications.

A general presumption of risk is not easily or defensibly justified in situations of weak associations or when diseases are common in the general population. A more productive approach may be to take the claims on a case-by-case basis, examining individual risk factors and overall risk profile. A general presumption of risk is more easily applied to unusual disorders with high relative risks, particularly when they are unique to or characteristic of certain occupations. Table 1 presents a summary of specific recommendations, with criteria that could be used to rebut, or question, presumption in the individual case.

Table 1. Summary of recommendations, with rebuttal criteria and special considerations, for compensation decisions.

A = epidemiological association but not sufficient for presumption of association with firefighting. NA = no consistent epidemiological evidence for association. NE = Not established. P = presumption of association with firefighting; risk exceeds doubling over general population. NP = no presumption; risk does not exceed doubling over general population. + = suggests increased risk due to firefighting. - = suggests increased risk due to exposures unrelated to firefighting. / = no likely contribution to risk.

Injuries

Injuries associated with firefighting are predictable: burns, falls and being struck by falling objects. Mortality from these causes is markedly increased among fire-fighters compared to other workers. Jobs in firefighting have a high risk of burns, especially, include those involving early entry and close-in firefighting, such as holding the nozzle. Burns are also more commonly associated with basement fires, recent injury before the incident and training outside the fire department of present employment. Falls tend to be associated with SCBA use and assignment to truck companies.

Ergonomics

Firefighting is a very strenuous occupation and is often performed under extreme environmental conditions. The demands of firefighting are sporadic and unpredictable, characterized by long periods of waiting between bouts of intense activity.

Fire-fighters maintain their level of exertion at a relatively constant, intense level once active firefighting begins. Any additional burden in the form of an encumbrance by protective equipment or victim rescue, however necessary for protection, reduces performance because fire-fighters are already exerting themselves to the maximum. The use of personal protection equipment has imposed new physiological demands on fire-fighters but has removed others by reducing exposure levels.

A great deal is known about the exertion characteristics of fire-fighters as a result of many careful studies on the ergonomics of firefighting. Fire-fighters adjust their levels of exertion in a characteristic pattern during simulated fire conditions, as reflected by heart rate. Initially, their heart rate increases rapidly to 70 to 80% of maximal within the first minute. As firefighting progresses, they maintain their heart rates at 85 to 100% maximal.

The energy requirements for firefighting are complicated by the severe conditions encountered in many inside fires. The metabolic demands of coping with retained body heat, heat from the fire and fluid loss through sweating add to the demands of physical exertion.

The most demanding activity known is building search and victim rescue by the “lead hand” (first fire-fighter to enter building), resulting in the highest average heart rate of 153 beats/minute and highest rise in rectal temperature of 1.3 °C. Serving as “secondary help” (entering a building at a later time to fight the fire or to conduct additional searches and rescues) is next most demanding, followed by exterior firefighting and serving as crew captain (directing the firefighting, usually at some distance from the fire). Other demanding tasks, in decreasing order of energy costs, are climbing ladders, dragging the fire hose, carrying a travelling ladder and raising a ladder.

During firefighting, core body temperature and heart rate follow a cycle over a period of minutes: they both increase slightly in response to work in preparation for entry, then both increase more as a result of environmental heat exposure and subsequently increase more steeply as a result of high work loads under conditions of heat stress. After 20 to 25 minutes, the usual length of time allowed for interior work by the SCBA used by fire-fighters, the physiological stress remains within limits tolerable by a healthy individual. However, in extended firefighting involving multiple re-entries, there is insufficient time between SCBA air bottle changes to cool off, leading to a cumulative rise in core temperature and an increasing risk of heat stress.

Personal Protection

Fire-fighters exert themselves to maximal levels while fighting fires. Under fire conditions, physical demands are complicated by the metabolic demands of coping with heat and loss of fluids. The combined effect of internally generated heat during work and of external heat from the fire may result in markedly increased body temperatures that climb to unusually high levels in an intense firefighting situation. Half-hour interval breaks to change SCBAs are not enough to arrest this climb in temperature, which can reach dangerous levels in prolonged firefighting. Although essential, personal protection, particularly SCBAs, imposes a considerable additional energy burden on the fire-fighter. The protective clothing also becomes much heavier when it gets wet.

The SCBA is an effective personal protection device that prevents exposure to the products of combustion when used properly. Unfortunately, it is often used only during the “knockdown” phase, when the fire is being actively fought, and not during the “overhaul” phase, when the fire is over but the debris is being examined and embers and smouldering flames are being extinguished.

Fire-fighters tend to judge the level of hazard they face by the intensity of smoke and decide whether to use an SCBA solely on the basis of what they see. This may be very misleading, after the flames are extinguished. While the fire scene may appear to be safe at this stage, it can still be dangerous.

The additional burden or energy cost of using personal protective equipment has been a major area of emphasis in occupational health research on firefighting. This undoubtedly reflects the degree to which firefighting is an extreme case of a matter of general interest, the implications for performance of using personal protection.

Although fire-fighters are obliged to use several forms of personal protection in their work, it is respiratory protection that is most problematic and which has received the most attention. A 20% decrement has been found in work performance imposed by carrying an SCBA, which is a substantial restraint under extreme and dangerous conditions. Investigations have identified several factors of importance in evaluating the physiological demands imposed by respirators in particular, among them the characteristics of the respirator, physiological characteristics of the user and the interactive effects with other personal protection and with environmental conditions.

The fire-fighter’s typical “turnout” gear may weigh 23 kg and imposes a high energy cost. Chemical protective clothing (17 kg), as used for clean-up of spills, is the next most demanding gear to wear, followed by the use of SCBA gear while wearing light clothing, which is only slightly more demanding than wearing light, flame-resistant clothing with a low-resistance mask. The firefighting apparatus has been associated with significantly greater retention of internally generated heat and rise in body temperature.

Fitness

Numerous studies have evaluated the physiological characteristics of fire-fighters, usually in the context of other studies to determine the response to firefighting-related demands.

Studies of the fitness of fire-fighters have shown fairly consistently that most fire-fighters are as or somewhat more fit than the general adult male population. They are not, however, necessarily fit to an athletically trained level. Fitness and health maintenance programmes have been developed for fire-fighters but have not been convincingly evaluated for their effectiveness.

The entrance of female applicants into firefighting has caused a re-evaluation of performance tests and studies comparing the sexes. In studies of trained individuals capable of achieving their potential maximum performance, rather than typical applicants, women demonstrated lower scores on average than men in all performance items, but a subgroup of women performed nearly as well in some tasks. The overall difference in performance was attributed primarily to lower absolute lean body weight, which correlated most strongly and consistently with performance differences. The most difficult tests for women were the stair-climbing exercises.

Back

Law enforcement is difficult, stressful, demanding work. There is evidence that much of the work is sedentary, but the small part of the work which is not sedentary is physically demanding. This is also the part of the work which is often the most critical. In this respect, police work has been likened to the work of a lifeguard at a swimming pool. Most of the time, the lifeguard is watching from the water’s edge, but when it is necessary to intervene the emotional and physical demands are extreme and there is usually no warning. Unlike the lifeguard, the police officer may be exposed to attack with a knife or a gun, and may be exposed to intentional violence from some members of the public. Routine activities include patrolling streets, subways, country roads, parks and many other areas. Patrols may be carried out on foot, in vehicles (such as automobiles, helicopters or snowmobiles) and sometimes on horseback. There is a need for constant vigilance and, in many parts of the world, there is the constant threat of violence. Police officers may be called upon to provide assistance to the public in cases of robbery, riot, assault or domestic disputes. They may be involved in crowd control, search and rescue, or assistance to the public in the event of natural disaster. There is an episodic need to chase criminals on foot or in a vehicle, to grapple with, tackle and control criminals and, occasionally, to resort to the use of a lethal weapon. Routine activities can escalate to life-threatening violence with little or no warning. Some police officers work undercover, sometimes for prolonged periods. Others, particularly forensic specialists, are exposed to toxic chemicals. Almost all are exposed to biohazard risk from blood and body fluids. Police officers usually work shifts. Often their shifts are extended by administrative work or court appearances. The actual physical demands of police work and the physical tasks of policing have been extensively studied and are remarkably similar in different police forces and different geographical locations. The question of whether any specific medical condition may be attributable to the occupation of policing is controversial.

Violence

Violence is, unfortunately, a reality of police work. In the United States the homicide rate for police is more than double that for the general population. Work-related violent assault is common among police officers. The particular activities that are likely to result in violent conflict have been the subject of much recent research. The notion that domestic dispute calls were particularly dangerous has been seriously questioned (Violanti, Vena and Marshall 1986). More recently, the activities most likely to result in the assault of a police officer were ranked as follows: First, arresting/controlling suspects; second, robbery in progress; and third, domestic dispute.

The type of violence to which police officers are exposed varies from one country to another. Firearms are more common in the United States than Britain or Western Europe. Countries where political unrest is recent may see police officers exposed to attack from large-calibre or automatic-fire weaponry of a military type. Knife wounds are encountered everywhere, but large-blade knives, particularly machetes, seem more common in tropical countries.

Police officers must maintain a high level of physical fitness. Police training must include training in the physical control of suspects where necessary, as well as training in the use of firearms and other types of tools such as CS gas, pepper spray or hand-held batons. Personal protective equipment such as the “bullet proof” vest is necessary in some communities. Similarly, a communication system that allows the police officer to summon assistance is often important. The most important training, however, must be in the prevention of violence. Current police theory underscores the idea of community policing, with the police officer an integral part of the community. It is to be hoped that as this approach replaces the philosophy of armed military incursion into the community, the need for weaponry and for armour will be reduced.

The sequelae of violence need not be physical. Violent encounters are exceedingly stressful. This stress is particularly likely if the incident has resulted in serious injury, bloodshed or death. Particularly important is the assessment for post-traumatic stress disorder (PTSD) after such incidents.

Emotional and Psychological Stress

It is apparent that police work is stressful. For many police officers the excess of paperwork, as opposed to active law enforcement, is seen as a major stressor. The combination of shiftwork and the uncertainty about what may happen during the shift provides a powerfully stressful situation. In times of fiscal restraint, these stressors are often dramatically amplified by inadequate staffing and inadequate equipment. Situations where there is a potential for violence are stressful in themselves; the stress is dramatically increased where staffing is such that there is inadequate back-up, or when the police officer is seriously overworked.

In addition, the high stress levels which may result from police work have been blamed for marital difficulties, alcohol abuse and suicides among police officers. Much of the data supporting such associations are variable from one geographic region to another. Nevertheless, these problems may well result from the occupation of police work in some cases.

The need for constant vigilance for evidence of stress-related problems or post-traumatic stress disorder cannot be overemphasized. Stress-related disease may manifest as behavioural problems, marital or family problems or, sometimes, as alcohol or substance abuse.

Atherosclerotic Heart Disease

There have been numerous studies suggesting that atherosclerotic disease is more common among police officers (Vena et al. 1986; Sparrow, Thomas and Weiss 1983); there are also studies suggesting that this is not the case. It has been suggested that the increase in the prevalence of heart disease among police officers was almost entirely due to the increased risk of acute myocardial infarction.

This is intuitively satisfying since it is well known that sudden exertion, in the face of underlying heart disease, is an important risk factor for sudden death. The functional job analysis for a general-duty constable clearly indicates that a police officer may be expected, in the course of duty, to go from the sedentary state to maximal exertion with little or no warning and with no preparation. Indeed, much police work is sedentary, but, when required, the police officer is expected to run and chase, to grapple and tackle, and to forcibly subdue a suspect. It is therefore not unexpected that even if the rate of underlying coronary disease is not much different among police officers than the rest of the population, the risk of suffering an acute myocardial infarction, because of the nature of the work, may well be higher (Franke and Anderson 1994).

The demographics of the police population must be considered when assessing the risks for heart disease. Heart disease is most commonly found among middle-aged men, and this group makes up a very large proportion of police officers. Women, who have a significantly lower rate of heart disease during their premenopausal years, are significantly under-represented in the demographics of most police forces.

If one is to effectively reduce the risk of cardiac disease in police officers, the regular assessment of the police officer, by a physician knowledgeable about police work and the potential cardiac risks that are associated with police work, is essential (Brown and Trottier 1995). The periodic health assessment must include health education and counselling about cardiac risk factors. There is good evidence that work-based health promotion programmes have a salutary effect on employee health and that the modification of cardiac risk factors reduces the risks of cardiac death. Smoking cessation programmes, nutritional advice, hypertension awareness and cholesterol monitoring and modification are all appropriate activities that will help modify risk factors for cardiac disease among police officers. Regular exercise may be particularly important in police work. The generation of a work environment that educates the worker about positive nutritional and lifestyle choices and that encourages such choices is likely to be beneficial.

Lung Disease in Police Work

The evidence suggests that the prevalence of lung disease in police work is lower than in the general population. There is, however, evidence of an increased rate of cancer of the respiratory system. The majority of police officers are not routinely exposed to inhaled toxins at a rate any greater than other residents of the communities they police. There are exceptions to this general rule, however, the most notable exception being police officers working in forensic identification. There is good evidence that these individuals may suffer from an increased prevalence of respiratory symptoms and, possibly, occupational asthma (Souter, van Netten and Brands 1992; Trottier, Brown and Wells 1994). Cyanoacrylate, used in uncovering latent fingerprints, is a known respiratory sensitizer. In addition to this, there are a large number of chemical carcinogens routinely used in this type of work. For these reasons it is recommended that police officers who work in forensic identification, particularly those who do fingerprint work, should undergo annual chest x ray and spirometry. Similarly, periodic health assessment of these officers must include a careful assessment of the respiratory system.

Even though the practice of smoking cigarettes is becoming less common, a significant number of police officers continue to smoke. This may be the reason why some studies have shown an increased risk of lung and laryngeal cancers among police officers. Smoking is, of course, a major risk factor for cardiac disease. It is also the leading cause of lung cancer. When a police officer gets lung cancer the question frequently asked is whether the cancer is due to occupational exposure, in particular to the carcinogens known to be present in fingerprint powders. If the police officer smokes, it will be impossible to confidently assign blame to any occupational exposure. In summary, respiratory disease is not normally an occupational hazard of police work except for forensic identification workers.

Cancer

There is some evidence that police officers suffer a somewhat higher risk of cancer than expected in the general population. In particular, the risk of digestive tract cancers such as cancer of the oesophagus, cancer of the stomach and cancer of the large bowel is reported to be elevated among police officers. There may be an increased risk of cancer of the lung and larynx. The risk of cancer among police officers working in forensic identification and forensic laboratory work has been briefly discussed above. The controversial issue of testicular cancer associated with the use of police “radar” to detect speeders must also be addressed.

The data suggesting an increase in the risk of cancer of the digestive tract among police officers is scant, but it is a question that must be seriously examined. In the case of lung and oesophageal cancer, it is difficult to see how the activities of police work would be expected to increase the risk. Smoking, of course, is known to increase the risk of both lung and oesophageal cancer, and significant numbers of police officers are known to continue to smoke cigarettes. Another substance known to increase the risk of oesophageal cancer is alcohol, particularly whisky. Police work is known to be exceedingly stressful, and there have been some studies that suggest police officers may sometimes use alcohol to relieve the tension and stress of their work.

The same research that demonstrated an increased risk of cancers of the digestive tract also demonstrated a peculiar increase in the incidence of cancers of the lymphatic and haemopoietic systems in some police officers. The increased risk was restricted to one group and the overall risk was not elevated. Given this very peculiar distribution, and the small numbers, this finding may well turn out to be a statistical aberration.

The risk of cancer among police officers involved in forensic identification work and forensic laboratory work has been discussed. The expected toxicities of chronic low-level exposure to various chemicals are determined by the level of exposure and the use of personal protective equipment. Based on these exposures a periodic health examination has been developed, performed annually and tailored to risks specific for these exposures.

Recent work has suggested a possible increase in the risk of skin cancer, including melanoma, among police officers. Whether this is due to the amount of sun exposure experienced by some police officers who work out of doors is purely speculative.

The question of cancer resulting from exposure to microwaves from “police radar” units has created much controversy. There is certainly some evidence that there may be clustering of certain kinds of cancers among police officers exposed (Davis and Mostofi 1993). The particular concern is about exposure from hand-held units. Alternatively, recent work with large populations refutes any risk of carcinogenicity from exposure to these units. Testicular cancer, in particular, has been reported to be associated with such exposure. The circumstance said to pose the greatest risk is that where the hand-held unit is turned on and resting on the lap of the police officer. This could result in considerable cumulative exposure of the testes over the long term. Whether such exposure causes cancer remains unproven. In the meantime it is recommended that police radar units be mounted outside the police car, be directed away from the police officer, not be used inside the car, be turned off when not in use and be tested regularly for microwave leakage. In addition the periodic examination of police officers should include careful palpation of the testes.

Back Pain

Low-back pain is a major cause of absenteeism throughout the Western world. It is a condition most common among middle-aged males. The factors which predispose to chronic low-back pain are multiple and some, such as the correlation to smoking, seem intuitively difficult to comprehend.

With respect to the occupation of driving, there is ample evidence that individuals who drive for a living are at a dramatically increased risk of low-back pain. This observation includes police officers for whom driving plays a significant part in their daily work. The majority of police cars continue to be equipped with the seats that were installed at the time of their manufacture. Various back supports and prosthetic devices are available which may improve the support of the lumbar spine, but the problem remains.

There is evidence that physical confrontation may play a role in the development of back pain. Motor vehicle accidents, particularly in police vehicles, may play a part. Some police equipment, such as thick leather belts festooned with heavy equipment, may also play a role.

It is important to remember that stress may precipitate or exacerbate back pain and that back pain, as a reason for sick-leave, may be perceived by some police officers as more acceptable than the need to recover from emotional trauma.

There is no doubt that specific exercises designed to maintain flexibility and strengthen the muscles of the back can significantly improve function and symptoms. Numerous classification systems of back pain have been promulgated. These different patterns of pain have distinct approaches of active intervention through specific muscle strengthening programmes. It is important that specific symptom patterns be sought out among police officers and that appropriate intervention and treatment be initiated. This requires periodic assessment by physicians knowledgeable in this clinical syndrome and capable of early effective intervention. It is equally important that a good level of overall fitness be maintained in order to avoid disability from this common chronic, costly syndrome.

Biohazard Risks

There are reports of police officers said to have contracted AIDS from their work. In May 1993 the US Federal Bureau of Investigations reported that there had been seven cases of police officers contacting AIDS through their work over 10 years (Bigbee 1993). Let us begin by noting that this is a surprisingly small number of cases over a 10-year period in the entire United States. Let us next observe that there was some controversy about whether these cases were all to be considered job-related. Nevertheless, it is clearly possible to become infected with HIV as a result of police work.

Since there is no cure for AIDS, and no vaccine that prevents the disease, the best defence a police officer has against this infection is prevention. Latex gloves should be worn, whenever possible, any time that contact with blood or blood-contaminated evidence is foreseen. This is especially important if there are any skin breaks on the hands.

Any open sores or cuts that a police officer has sustained must be kept covered with an occlusive dressing while on duty. Needles should be handled with extreme care, and needles or syringes must be transported in a sharps container that can effectively prevent the needle from penetrating through the container. Sharp edges must be avoided and sharp exhibits handled with extreme care, particularly when contaminated with fresh blood. Where possible, such exhibits should be picked up with instruments rather than by hand.

Latex gloves and a barrier mask should be used if resuscitation attempts are undertaken, and latex gloves must always be worn when rendering first aid. It is important to bear in mind, however, that the risk of becoming infected with HIV from resuscitation procedures is very remote.

There are also some traditional techniques in policing that must be avoided. “Pat down” searches are dangerous to the police officer. There are numerous cases of police officers suffering needle stick injuries from this type of procedure. Also dangerous is searching containers, bags or even pockets by rummaging through them. All containers must be emptied into a flat surface and their contents examined in plain view. Similarly sweep searches under car seats and between seats and backs of couches and chairs must not be performed. It is preferable to dismantle furniture rather than have police officers putting their hands blindly in places where needles and syringes may be hidden. Latex gloves do not protect from needlestick injury.

Eye protection and face masks may be appropriate in circumstances where spatter of body fluid such as saliva or blood can reasonably be foreseen. There must be a system in place for the safe disposal of personal protective equipment. There must be a facility for police officers to wash their hands. Given the fact that few patrol cars have running water and sinks, prepackaged washing solutions for cleaning skin should be provided. Lastly, the question of what should be done for a police officer who, in spite of all the best precautions, suffers a percutaneous exposure to HIV should be asked. After appropriate wound care the first step is to try to determine whether the source of the exposure is truly HIV positive. This is not always possible. Secondly, it is imperative that the police officer be educated about the true risks of infection. Many non-medical personnel assume that the risk is much higher than it really is. Thirdly, the police officer must be informed of the need to retest for at least six months and possibly nine months in order to ensure that the officer has not been infected. Steps must be taken to prevent potential infection of the officer’s sexual partner(s) for at least six months. Lastly, the question of post-exposure prophylaxis must be discussed. There is increasing evidence that prophylaxis with antiviral drugs may be helpful in reducing the risk of seroconversion after percutaneous exposure. These are discussed elsewhere in the Encyclopaedia. In addition, the area of prophylaxis is under intense research scrutiny so that current references must be consulted to assure the most appropriate approach.

There are numerous case reports of occupationally acquired hepatitis among law enforcement personnel. The quantitative risk is not dramatically high when compared to other occupations. Nevertheless it is a real risk and must be seen as a possible occupational disease. The preventive approach to HIV infection that was outlined above applies equally well to the blood-borne disease hepatitis B. Given the fact that hepatitis B is so much more contagious than AIDS, and more likely to cause disease or death in the short term, this disease ought to be an even more compelling reason for following universal precautions.

There is an effective vaccine against hepatitis B. All police officers regardless of whether they are involved in forensics or general-duty policing, should be vaccinated against hepatitis B. Other conditions, including hepatitis C, tuberculosis and airborne pathogens, may also be encountered by police officers.

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Growing security needs as a result of generally rising criminal activity, the opening of the borders to the East and within the European Union, as well as the accession of the former German Democratic Republic, have led to a disproportionate growth in the number of commercial guard and security companies as well as the number of employees of these companies in Germany.

At the start of 1995 the number of employees in the more than 1,200 guard and security companies stood at over 155,000. The mid-sized companies have mostly 20 to 200 employees. There are also companies, however, with fewer than 10 employees and others with several thousand. Company mergers are increasingly common.

The Administration Trade Organization is responsible for legal accident insurance for these companies and their employees.

Accident Prevention Regulations

Background of the accident prevention regulations and their scope of application

With the rising occurrence of accidents, the “Guard and Security Services” (VBG 68) Accident Prevention Regulation that had been in force since May 1964 in guard and security work became outdated. It has therefore been reworked and completely redrafted, with the participation of representatives of the affected employers, employees, accident insurance companies, manufacturers’ and trade organizations as well as representatives of the Federal Minister of Labour and Social Questions, the state industrial oversight authorities, the Federal Minister of Defence, the Federal Crime Office, the state police authorities, other institutions and a specialized committee. This committee is an organ of the central office of the Safety and Health Trade Organization of the industrial trade organizations, under the responsibility of the Administration Trade Organization.

The newly drafted accident regulation went into effect 1 October 1990, after several years of consultations. The regulation is the legal standard for all employers and employees in guard and security companies. It lays out duties and lines of authority upon which newly drafted governmental ordinances specific to each specialty are based.

Guard and security work to protect persons and valuables includes:

• private guard duty, such as gate-keepers and park watchmen

• security at construction sites and rail yards

• guarding private property, including factory guards

• guarding military installations and atomic power plants

• ranger and patrol duty on various properties

• security service for performances, trade fairs and expositions

• crowd control

• courier service

• investigative services

• money and valuables transport

• personal protection

• staffing alarm centres

• responding to alarms.

General responsibilities of the employer

The employer or his or her agent may employ only persons who are currently qualified and adequately instructed for the desired guard and security activity. These qualifications are set out in writing.

The conduct of the personnel, including notification of deficiencies and particular dangers, must be regulated with detailed service instructions.

If particular dangers result from guard and security work, adequate supervision of the personnel must be ensured.

Guard and security tasks should be taken on only when avoidable dangers in the working area have been eliminated or secured. To this end, the scope and course of the security, including known side activities, must be set out in writing.

The employer or his or her agent, independent of the client’s duties, must ensure that the property to be secured has been inspected for dangers. Records of these inspections must be kept. These inspections must take place on a regular basis and also immediately when the occasion warrants.

The employer or his or her agent must require of the client that avoidable dangers be eliminated or dangerous locations be secured. Until these security measures are implemented, regulations should be formulated that guarantee the safety of the guard and security personnel in another manner. Inadequately secured danger zones should be excluded from surveillance.

The guard and security personnel must be instructed on the property to be secured and its specific dangers during the time period when the guard and safety activity will take place.

The guard and security personnel must be supplied with all necessary facilities, equipment and resources, especially appropriate footwear, effective flashlights in darkness, as well as personal protective gear in good condition, as needed. The personnel must be adequately instructed in the use of such resources. Equipment and other resources that are worn must not unduly restrict freedom of movement, especially of the hands.

General duties of the employee

Employees must abide by all occupational safety measures and follow the service instructions. They should not accede to any directives from the client that contravene the safety instructions.

Deficiencies and dangers that are discovered, as well as corrective measures taken, must be reported to the employer or his or her agent.

The employees must use the equipment and resources provided appropriately. They may not use or enter installations if not authorized.

Employees must not use alcoholic beverages or other intoxicants while on duty. This also applies for an appropriate time period before work: the employee must start work sober.

Employees who must wear glasses to correct their vision during guard or security work must secure these against loss or bring a replacement pair. This also applies to contact lenses.

Use of dogs

In general, only dogs tested and approved by appropriately certified and competent dog handlers are to be used for guard and security work. Untested dogs should be used only for warning tasks when they are clearly under the control of their handler, but not for additional security tasks. Dogs that have vicious tendencies or that are no longer sufficiently competent must not be used.

Excessive demands should not be put on the dogs. Adequate education and training based on the results of research on animal behaviour must be provided. Proper limits for period of service, minimum rest times and total daily service times need to be set.

The competence of the dog handler must be regularly certified. If the handler is no longer adequately qualified, authorization to handle dogs should be withdrawn.

Regulations must be formulated to guarantee smooth and safe handling of dogs, contact with the dog, the taking over and turning over of the dog, leashing and unleashing, a uniform set of commands used by different handlers, the handling of the leash and conduct when third persons are encountered.

Minimal requirements are prescribed for dog kennels concerning condition and equipping as well as setting access authorization.

When transporting dogs, a separation between transport area and passenger area must be maintained. Car trunks are not suitable under any circumstances. Separate facilities for each dog must be provided.

Use of firearms

Employees must use firearms only on express instructions of the employer or his or her agent, in accordance with all legal requirements and only when the employee is appropriately reliable, suited and trained.

Those carrying firearms must regularly participate in target practice at authorized firing ranges and prove their skill and knowledge. Corresponding records must be kept. If an employee no longer fulfils the requirements, firearms must be withdrawn.

Only officially tested and approved firearms are to be used. The firearms should be tested by experts periodically, and also whenever an inadequacy is suspected; they must be repaired by trained and officially approved persons.

Guards and security personnel must not have or use blank- or gas-firing weapons. In confrontations with armed perpetrators, these weapons provide a false sense of security that leads to extreme danger without adequate possibility of self-defence.

Strict regulations guarantee the flawless and safe use, carrying, transfer, loading and unloading, and storage of firearms and ammunition.

Transporting money and valuables

Due to the high risk of robbery, at least two couriers must be employed for transporting money in publicly accessible areas. One of these must be exclusively occupied with security. This applies also to the couriers’ movements between money transport vehicles and the locations where the money is picked up or delivered.

Exceptions are permitted only if: (1) the money transport is not recognizable by outsiders as a transport of money either from the clothing or equipment of the personnel, or from the vehicle used, the route taken or the course of the transport; (2) the incentive for robbery is significantly reduced by technical equipment that must be clearly recognizable by outsiders; or (3) only coin is being transported, and this is clearly recognizable by outsiders from the conduct and course of the transport.

Technical equipment that considerably reduces the incentive for robbery includes, for example, devices that either constantly or during the entire transport are firmly attached to the money transport container and that, in the case of a forced conveyance or snatching during delivery, automatically either immediately or after a timed delay set off an optical alarm by means of a release of coloured smoke. Additional devices such as simultaneous acoustic alarms are advisable.

The design, form, size and weight of money transport containers must be adequately manageable for carrying. They must not be attached to the courier, as this poses an increased risk.

Money transport with vehicles should in general be carried out only in vehicles specially secured for this purpose. These vehicles are adequately secured when their construction and equipment meet the requirements of Accident Prevention Regulation “Vehicles” (VBG 12) and especially the “Safety Rules for Money Transport Vehicles” (ZH1/209).

Money transport in unsecured vehicles is permissible only when exclusively coin, clearly recognizable as such, is being transported, or it is completely unrecognizable as a transport of money. In this case neither the clothing nor equipment of the personnel, nor the construction, equipping or markings of the vehicle used should indicate that money is being transported.

Transport times and routes as well as loading and unloading locations needs to be varied. Money transport vehicles must also be constantly occupied by at least one person behind barred doors during loading and unloading in public areas.

Alarm centres and vaults

Alarm centres and vaults must be adequately secured against assault. The minimal requirements are the Accident Prevention Regulation “Tellers’ windows” (VBG 120), which governs securing and equipping credit and money-changing institutions that deal with cash.

Final Considerations

There are practical limits in all attempts to improve occupational safety. This is especially clear in guard and security work. Whereas in other areas, structural measures and improvements lead to success, these play only a secondary role in guard and security work. Significant improvements in this area ultimately can be achieved only by changing the company organizational structure and human conduct. The newly drafted Accident Prevention Regulation “Guard and Security Services” (VBG 68), which may seem exaggerated and too detailed on superficial viewing, nevertheless takes this basic knowledge into very particular consideration.

Thus it is not surprising that since regulations have taken effect, the reportable accidents and occupational diseases in commercial guard and security companies have declined by about 20%, despite the generally increasing crime rate. Some companies which have especially conscientiously implemented the Accident Prevention Regulation, and additionally have voluntarily applied supplementary security measures based on a criteria catalogue that is available, were able to register decreases in occurrences of accidents and occupational diseases of up to 50%. This was especially true in the use of dogs.

Furthermore, the totality of the measures taken led to a reduction in the mandatory premiums for legal accident insurance for commercial guard and security companies, despite rising costs.

Overall it is clear that secure conduct can be achieved in the long run only with precise norms and organizational regulations, as well as through constant training and checking.

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Nations maintain military forces to deter aggression, discourage conflict and, should the need arise, to be prepared to fight and win their wars. Military forces are also used in non-combat roles that are referred to as “peacetime engagements” or “operations other than war”. These include: humanitarian missions such as emergency disaster assistance; peacemaking and peacekeeping operations; counter-drug and counter-terrorism work; and security assistance.

Men and women of the armed forces work under the sea, on surface ships, above the earth, on all kinds of terrain, in extremes of temperature and at high elevations. Many military jobs relate to maintaining the skills needed to operate equipment unique to the military (like submarines, fighter aircraft and tanks) in action against an armed enemy. The military also has a large number of uniformed people who perform maintenance, repair, administrative, medical and other functions to support those who fight battles.

All military people maintain proficiency in basic military skills, such as marksmanship, and a high level of physical fitness so that they may react appropriately if they become involved in warfare. Exercise programmes are used extensively to develop and maintain strength and aerobic fitness. If used in excess or poorly managed, these programmes may cause excessive injuries.

In addition to their job exposures, uniformed people are often at enhanced risk of acquiring infectious diseases. Basic training camp environments and close living spaces, as found on ships, may contribute to outbreaks of acute respiratory and other infectious diseases. Noise is a universal problem. Also, service in many parts of the world brings with it exposure to contaminated food and water, and to disease vectors carrying protozoan, viral and bacterial agents.

The armed forces rely on many civilian employees to do research and development and provide maintenance, administrative and other support services. Some civilians are paid by the military; others work for companies under contract to the military. In the past, civilian workers did not routinely accompany members of the armed forces into hostile areas. Recently, civilians have been performing many support functions in close proximity to deployed military forces, and may face similar occupational and environmental exposures.

The Fixed Workplace

In many fixed military facilities (such as repair depots, administrative offices and hospitals) uniformed members and civilians perform operations that are similar to those found in non-military workplaces. These include painting; degreasing; welding; grinding; chipping; electroplating; handling hydraulic fluids, fuels and cleaning agents; using microcomputers; and managing patients with infectious diseases. However, performing industrial operations in confined spaces in ships and submarines, or inside armoured vehicles, increases the risk of overexposure to toxicants. Additionally, some work must be done by divers at various depths.

In some fixed facilities, militarily unique items are developed, manufactured, serviced or stored. These items may include: nerve and mustard agent munitions; military explosives, propellants and special fuels, such as hydroxylammonium nitrate; laser range finders and target designators; microwave radiation sources in radar and communications equipment; and ionizing radiation from munitions, armour and nuclear power plants. Composite materials are not militarily unique but are common in military equipment. Where older military equipment is used, workers may be exposed to polychlorinated biphenyls in electrical systems, asbestos in the lagging around steam pipes and lead-based paints.

The Militarily Unique Workplace

People in the armed forces are always on duty, but commanders try to maintain acceptable work-rest cycles. However, battles are not fought on prearranged schedules, and military forces train as they expect to fight. During intense training, fatigue and sleep deprivation are common. The situation is worsened by quickly transporting military forces across time zones and having them perform their jobs immediately upon arrival. In all military operations, and particularly large operations that cover wide areas and involve air, land and sea forces from different countries, there is considerable pressure to maintain effective coordination and communication among the various elements to reduce the risk of accidents, such as placing weapons fire upon a friendly target. Stress is increased if operations result in long family separations, or if the possibility of hostile action exists.

Naval Vessels

On naval vessels, the tight spaces, multiple doors and ladders and narrow passageways close to operating equipment are hazardous. The confined spaces also restrict movement during work and contribute to ergonomic injuries (see figure 1). In submarines, air quality is a major concern that requires constant monitoring and the restriction of unnecessary contaminants. In all military environments where exposure to nuclear power plants, nuclear weapons or other radioactive material may occur, exposures are assessed, controls are implemented and monitoring is conducted as appropriate.

Figure 1.  On aircraft carriers, naval flight deck personnel must work in extremely close proximity to operating fixed-wing jets and helicopters, and their associated safety hazards, exhaust combustion products and noise.

US Army

Aircraft

Flight operations in the aerospace environment involve a variety of fixed-wing and rotary-wing (helicopter) aircraft. Military air crews experience exposures that are different from those in the civilian environment. Many military aircraft are unique in their design, flight characteristics and mission performance. Air crew members are frequently at risk of exposure to excessive accelerative forces (centrifugal and gravitational), decompression sickness, circadian desynchrony resulting from long missions or night operations and spatial disorientation. Vibration originating from the aircraft and/or atmospheric turbulence may affect vision, result in motion sickness, produce fatigue and contribute to the development of disorders of the lumbar spine, particularly in helicopter pilots. Exposure to products of combustion from engine exhaust, overheating or burning of aircraft components may pose a toxic hazard if the aircraft is damaged during combat operations. Fatigue is a major concern when flight operations occur over extended periods of time, or involve long distances. Spatial disorientation and illusionary sensations of aircraft attitude and motion can be causes of mishaps, particularly when flights occur at high speeds in close proximity to the ground. Ground crews may be under considerable time pressure to perform maintenance and resupply (often with aircraft engines running) under difficult working conditions.

Helicopters are used extensively in the military as low-altitude weapons systems and observation platforms, and as medical evacuation and utility vehicles. These rotary-wing aircraft are associated with unique physical hazards, mission profiles and physiological implications for air crews. Helicopters have the ability to fly forward, sideward and rearward, but are inherently unstable flight platforms. Consequently, helicopter air crews must maintain constant concentration and have exceptional vision and muscle coordination to operate flight control systems and avoid collisions with terrain and other obstructions during low-level flight.

Fatigue is a serious concern for crew members involved in extended flights, large numbers of short missions and/or low-level, nap-of-the-earth (NOE) flights in which pilots fly as close to terrain contours as the speed and performance contours will allow. Low-level flights at night are particularly challenging. Night vision goggles are commonly used by helicopter pilots in military aviation and law enforcement; however, their use may restrict depth perception, field of view and colour differentiation. Engines, transmissions and rotors of helicopters produce unique vibration spectra which can adversely affect visual acuity and contribute to muscle strain and fatigue. These aircraft components also produce intense noise levels which can disrupt cockpit communications and contribute to hearing loss. Shrouds enclosing noisy components, acoustic blankets as insulation in cockpit/cabin areas and hearing protective devices are used to reduce the risk of hearing loss. Heat stress may be a special problem for helicopter air crews given the lower altitudes at which helicopters operate. Helicopter crashes tend to involve vertical impacts with the ground, often at relatively low forward speeds (in contrast to the longitudinal pattern of fixed-wing aircraft). Compression fractures of the spine and basilar skull fractures are common injuries in crash victims. Design features employed to prevent and control injuries include protective helmets, crash-worthy fuel systems, strengthened cockpit areas to prevent intrusion of the rotor system or transmission, and special seats and restraint systems utilizing shock-absorbing devices.

Ground Forces

Ground troops fire rifles, large guns and rockets, and ride in vehicles over rough terrain. At times they work under the cover of smokes produced from fog oil, diesel fuel or other chemicals (see figure 2). Exposures to noise, blast overpressure from large guns, vibration and propellant combustion products are common. Ballistic eye injuries occur but can be prevented by protective eyewear. The possibility of adverse health effects is increased when rockets and large guns are fired in enclosed areas, as in buildings. Armoured vehicle crew compartments are closed spaces where carbon monoxide concentrations may reach thousands of parts per million after weapons firing, and require effective ventilation systems. Heat stress in some vehicles may necessitate the use of cooling vests. Troops may also experience heat stress from wearing special clothing, hoods and masks to protect against chemical and biological agent attacks. These personal protective measures may contribute to accidents because of interference with vision and mobility. In field medical facilities, infection control practices and containment of waste anaesthetic gases may present unique challenges.

Figure 2.  This mechanized smoke generator produces a curtain of fog oil smoke through heat evaporation; fog oil may cause a slipping hazard.

US Army

Military personnel face injury and illness from a variety of weapons. The more conventional weapons produce casualties using projectiles and fragments, blast effects (which may result in lung contusion trauma) and flame and incendiary devices, such as those containing napalm and phosphorus. Eye injuries from lasers may occur accidentally or when lasers are used as offensive weapons. Other weapons systems employ biological material, such as anthrax spores, or chemicals like anticholinesterase agents.

Extensive use of mines has caused concern because of the casualties that have occurred in civilian non-combatants. Narrowly defined, a mine is an explosive ordinance designed to be buried in the ground. In reality, a mine is any hidden explosive that lies in wait and may be detonated by enemy forces, friendly forces, non-combatants or animals. Mines may be employed against matériel or people. Anti-matériel mines are directed at military vehicles and may contain about 5 to 10 kg of explosive, but require 135 kg or more of compressive force to be activated. Antipersonnel mines are designed to maim rather than to kill. Less than 0.2 kg of explosive buried in the ground can blow off a foot. The dirt particles surrounding a mine become missiles that grossly contaminate wounds. The radius in which a mine can produce casualties was expanded with the development of the “pop-up mine”. In these mines a small explosive charge sends a canister about a metre into the air. The canister immediately detonates, spraying fragments to a distance of 35 m. Modern mine designs, like the “Claymore”, can be detonated electrically, by timed fuse or by a trip wire, and can send hundreds of steel spheres, each weighing 0.75 g, over a 60° arc for distances up to 250 m. Within 50 m, gross mutilation and lethal injuries are common.

A range of chemical agents have been employed in warfare. Herbicides (e.g., 2,4-D n-butyl ester mixed with 2,4,5-T n-butyl ester, also known as Agent Orange) were used in Vietnam to control terrain. Some chemicals (e.g., tear gas) have been used as incapacitating agents to produce transient physical or mental effects, or both. Other chemicals are extremely toxic and capable of producing serious injury or death. This category includes the anticholinesterase agents (e.g., Tabun and Sarin), the vesicants or blister agents (e.g., mustard and arsenicals), the lung-damaging or “choking” agents (e.g., phosgene and chlorine) and the blood agents that block the oxidative processes (e.g., hydrogen cyanide and cyanogen chloride).

In addition to armed conflict, other potential sources of exposure to chemical agents include: terrorist activities; storage sites for old military chemical stocks, where leaking containers may occur; sites where military chemical stocks are being destroyed through incineration or other means; and the accidental unearthing of old, forgotten chemical disposal sites.

The Medical Care System

Medical care for the armed forces and civilian workers is focused on prevention. Often, medical personnel study military vehicles and equipment during development to identify potential health hazards to users and maintainers so that these can be controlled. Training and user manuals and educational programmes address protection against hazards. Medical care includes initial medical screening, periodic medical assessment, health education and promotion, and disability evaluations, in addition to primary care and emergency services. Medical personnel also participate in accident investigations. When people deploy to areas presenting new health risks, medical risk assessments are used to identify threats and interventions like vaccines, prophylactic drugs, personnel protective measures and educational programmes.

Medical personnel who provide preventive and primary care to members of the armed forces must be knowledgeable about the characteristics of weapons used in training and on the battlefield to: predict and prepare for the casualties that may occur; take preventive actions that may reduce morbidity and/or mortality; and provide appropriate treatment when casualties do occur. Personal protective equipment is important in defending against chemical and biological agents and eye injuries from missiles and lasers. Other measures to be considered are vaccines and chemoprophylactic drugs for biological agents, and drug pre-treatment and antidotes for chemical agents. Training medical personnel in the early detection and management of illnesses and injuries caused by weapons is critical. Early recognition can result in rapid initiation of appropriate therapy and possibly a reduction in future morbidity and mortality. Also, military surgical staffs are better prepared to take care of their patients and themselves if they are knowledgeable about the wounds they are treating. For example: wounds made by high-velocity rifles often do not require extensive debridement for soft-tissue destruction; wounds made by fragmentation bullets may require extensive exploration; and wounds may contain unexploded munitions.

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