CONTENTS

Chapter Editor                                                                                       Gunnar Nordberg

• General Profile

• Acknowledgements

• Aluminium

• Antimony

• Arsenic

• Barium

• Bismuth

• Cadmium

• Chromium

• Copper

• Iron

• Gallium

• Germanium

• Indium

• Iridium

• Lead

• Magnesium

• Manganese

• Metal Carbonyls (especially Nickel Carbonyl)

• Mercury

• Molybdenum

• Nickel

• Niobium

• Osmium

• Palladium

• Platinum

• Rhenium

• Rhodium

• Ruthenium

• Selenium

• Silver

• Tantalum

• Tellurium

• Thallium

• Tin

• Titanium

• Tungsten

• Vanadium

• Zinc

• Zirconium and Hafnium

Back

In the following article, the term cardiovascular diseases (CVDs) refers to organic and functional disorders of the heart and circulatory system, including the resultant damage to other organ systems, which are classified under numbers 390 to 459 in the 9th revision of the International Classification of Diseases (ICD) (World Health Organization (WHO) 1975). Based essentially on international statistics assembled by the WHO and data collected in Germany, the article discusses the prevalence of CVDs, new disease rates, and frequency of deaths, morbidity and disability.

Definition and Prevalence in the Working-Age Population

Coronary artery disease (ICD 410-414) resulting in ischaemia of the myocardium is probably the most significant CVD in the working population, particularly in industrialized countries. This condition results from a constriction in the vascular system that supplies the heart muscle, a problem caused primarily by arteriosclerosis. It affects 0.9 to 1.5% of working-age men and 0.5 to 1.0% of women.

Inflammatory diseases (ICD 420-423) may involve the endocardium, the heart valves, the pericardium and/or the heart muscle (myocardium) itself. They are less common in industrialized countries, where their frequency is well below 0.01% of the adult population, but are seen more frequently in developing countries, perhaps reflecting the greater prevalence of nutritional disorders and infectious diseases.

Heart rhythm disorders (ICD 427) are relatively rare, although much media attention has been given to recent instances of disability and sudden death among prominent professional athletes. Although they can have a significant impact on the ability to work, they are often asymptomatic and transitory.

The myocardiopathies (ICD 424) are conditions which involve enlargement or thickening of the heart musculation, effectively narrowing the vessels and weakening the heart. They have attracted more attention in recent years, largely because of improved methods of diagnosis, although their pathogenesis is often obscure. They have been attributed to infections, metabolic diseases, immunologic disorders, inflammatory diseases involving the capillaries and, of particular importance in this volume, to toxic exposures in the workplace. They are divided into three types:

• dilative—the most common form (5 to 15 cases per 100,000 people), which is associated with the functional weakening of the heart
• hypertrophic—thickening and enlargement of the myocardium resulting in relative insufficiency of the coronary arteries
• restrictive—a rare type in which myocardial contractions are limited.

Hypertension (ICD 401-405) (increased systolic and/or diastolic blood pressure) is the most common circulatory disease, being found among 15 to 20% of working people in industrialized countries. It is discussed in greater detail below.

Atherosclerotic changes in the major blood vessels (ICD 440), often associated with hypertension, cause disease in the organs they serve. Foremost among these is cerebrovascular disease (ICD 430-438), which may result in a stroke due to infarction and/or haemorrhage. This occurs in 0.3 to 1.0% of working people, most commonly among those aged 40 and older.

Atherosclerotic diseases, including coronary artery disease, stroke and hypertension, by far the most common cardiovascular diseases in the working population, are multifactorial in origin and have their onset early in life. They are of importance in the workplace because:

• so large a proportion of the workforce has an asymptomatic or unrecognized form of cardiovascular disease
• the development of that disease may be aggravated or acute symptomatic events precipitated by working conditions and job demands
• the acute onset of a symptomatic phase of the cardiovascular disease is often attributed to the job and/or the workplace environment
• most individuals with an established cardiovascular disease are capable of working productively, albeit, sometimes, only after effective rehabilitation and job retraining
• the workplace is a uniquely propitious arena for primary and secondary preventive programmes.

Functional circulatory disorders in the extremities (ICD 443) include Raynaud’s disease, short-term pallor of the fingers, and are relatively rare. Some occupational conditions, such as frostbite, long-term exposure to vinyl chloride and hand-arm exposure to vibration can induce these disorders.

Varicosities in the leg veins (ICD 454), often improperly dismissed as a cosmetic problem, are frequent among women, especially during pregnancy. While a hereditary tendency to weakness of the vein walls may be a factor, they are usually associated with long periods of standing in one position without movement, during which the static pressure within the veins is increased. The resultant discomfort and leg oedema often dictate change or modification of the job.

Annual incidence rates

Among the CVDs, hypertension has the highest annual new case rate among working people aged 35 to 64. New cases develop in approximately 1% of that population every year. Next in frequency are coronary heart disease (8 to 92 new cases of acute heart attack per 10,000 men per year, and 3 to 16 new cases per 10,000 women per year) and stroke (12 to 30 cases per 10,000 men per year, and 6 to 30 cases per 10,000 women per year). As demonstrated by global data collected by the WHO-Monica project (WHO-MONICA 1994; WHO-MONICA 1988), the lowest new incidence rates for heart attack were found among men in China and women in Spain, while the highest rates were found among both men and women in Scotland. The significance of these data is that in the population of working age, 40 to 60% of heart attack victims and 30 to 40% of stroke victims do not survive their initial episodes.

Mortality

Within the primary working ages of 15 to 64, only 8 to 18% of deaths from CVDs occur prior to age 45. Most occur after age 45, with the annual rate increasing with age. The rates, which have been changing, vary considerably from country to country (WHO 1994b).

Table 3.1 [CAR01TE] shows the death rates for men and for women aged 45 to 54 and 55 to 64 for some countries. Note that the death rates for men are consistently higher than those for women of corresponding ages. Table 3.2 [CAR02TE] compares the death rates for various CVDs among people aged 55 to 64 in five countries.

Work Disability and Early Retirement

Diagnosis-related statistics on time lost from work represent an important perspective on the impact of morbidity on the working population, even though the diagnostic designations are usually less precise than in cases of early retirement because of disability. The case rates, usually expressed in cases per 10,000 employees, provide an index of the frequency of the disease categories, while the average number of days lost per case indicates the relative seriousness of particular diseases. Thus, according to statistics on 10 million workers in western Germany compiled by the Allgemeinen Ortskrankenkasse, CVDs accounted for 7.7% of the total disability in 1991-92, although the number of cases for that period was only 4.6% of the total (table 3.3 [CAR03TE]). In some countries, where early retirement is provided when work ability is reduced due to illness, the pattern of disability mirrors the rates for different categories of CVD.

Aetiological Factors

Head trauma consists of skull injury, focal brain injury and diffuse brain tissue injury (Gennarelli and Kotapa 1992). In work-related head trauma falls account for the majority of the causes (Kraus and Fife 1985). Other job-related causes include being struck by equipment, machinery or related items, and by on-road motor vehicles. The rates of work-related brain injury are markedly higher among young workers than older ones (Kraus and Fife 1985).

Occupations at Risk

Workers involved in mining, construction, driving motor vehicles and agriculture are at higher risk. Head trauma is common in sportsmen such as boxers and soccer players.

Neuropathophysiology

Skull fracture can occur with or without damage to the brain. All forms of brain injury, whether resulting from penetrating or closed head trauma, can lead to the development of swelling of the cerebral tissue. Vasogenic and cytogenic pathophysiologic processes active at the cellular level result in cerebral oedema, increased intracranial pressure and cerebral ischaemia.

Focal brain injuries (epidural, subdural or intracranial haematomas) may cause not only local brain damage, but a mass effect within the cranium, leading to midline shift, herniation and ultimately brain stem (mid-brain, pons and medulla oblongata) compression, causing, first a declining level of consciousness, then respiratory arrest and death (Gennarelli and Kotapa 1992).

Diffuse brain injuries represent shearing trauma to innumerable axons of the brain, and may be manifested as anything from subtle cognitive dysfunction to severe disability.

Epidemiological Data

There are few reliable statistics on the incidence of head injury from work-related activities.

In the United States, estimates of the incidence of head injury indicate that at least 2 million people incur such injuries each year, with nearly 500,000 resultant hospital admissions (Gennarelli and Kotapa 1992). Approximately half of these patients were involved in motor accidents.

A study of brain injury in residents of San Diego County, California in 1981 showed that the overall work-related injury rate for males was 19.8 per 100,000 workers (45.9 per 100 million work hours). The incidence rates of work-related brain injuries for male civilian and military personnel were 15.2 and 37.0 per 100,000 workers, respectively. In addition, the annual incidence of such injuries was 9.9 per 100 million work hours for males in the work force (18.5 per 100 million hours for military personnel and 7.6 per 100 million hours for civilians) (Kraus and Fife 1985). In the same study, about 54% of the civilian work-related brain injuries resulted from falls, and 8% involved on-road motor vehicle accidents (Kraus and Fife 1985).

Signs and Symptoms

The signs and symptoms vary among different forms of head trauma (table 1) (Gennarelli and Kotapa 1992) and different locations of traumatic brain lesion (Gennarelli and Kotapa 1992; Gorden 1991). On some occasions, multiple forms of head trauma may occur in the same patient.

Table 1. Classification of traumatic head injuries.

Skull injuries

Fractures of cerebral vault, either linear or depressed, can be detected by radiological examinations, in which the location and depth of the fracture are clinically most important.

Fractures of the skull base, in which the fractures are usually not visible on conventional skull radiographs, can best be found by computed tomography (CT scan). It can also be diagnosed by clinical findings such as the leakage of cerebropinal fluid from the nose (CSF rhinorrhea) or ear (CSF otorrhea), or subcutaneous bleeding at the periorbital or mastoid areas, though these may take 24 hours to appear.

Focal brain tissue injuries (Gennarelli and Kotapa 1992;Gorden 1991)

Haematoma:

Epidural haematoma is usually due to arterial bleeding and may be associated with a skull fracture. The bleeding is seen distinctly as a biconvex density on the CT scan. It is characterized clinically by transient loss of consciousness immediately after injury, followed by a lucid period. Consciousness may deteriorate rapidly due to increasing intracranial pressure.

Subdural haematoma is the result of venous bleeding beneath the dura. Subdural haemorrhage may be classified as acute, subacute or chronic, based on the time course of the development of symptoms. Symptoms result from direct pressure to the cortex under the bleed. The CT scan of the head often shows a crescent-shaped deficit.

Intracerebral haematoma results from bleeding within the parenchyma of the cerebral hemispheres. It may occur at the time of trauma or may appear a few days later (Cooper 1992). Symptoms are usually dramatic and include an acutely depressed level of consciousness and signs of increased intracranial pressure, such as headache, vomiting, convulsions and coma. Subarachnoid haemorrhage may occur spontaneously as the result of a ruptured berry aneurysm, or it may be caused by head trauma.

In patients with any form of haematoma, deterioration of consciousness, ipsilateral dilated pupil and contralateral haemiparesis suggests an expanding haematoma and the need for immediate neurosurgical evaluation. Brain stem compression accounts for approximately 66% of deaths from head injuries (Gennarelli and Kotapa 1992).

Cerebral contusion:

This presents as temporary loss of consciousness or neurologic deficits. Memory loss may be retrograde—loss of memory a time period before the injury, or antegrade—loss of current memory. CT scans shows multiple small isolated haemorrhages in the cerebral cortex. Patients are at higher risk of subsequent intracranial bleeding.

Diffuse brain tissue injuries (Gennarelli and Kotapa 1992;Gorden 1991)

Concussion:

Mild concussion is defined as a rapidly resolving (less than 24 hours) interruption of function (such as memory), secondary to trauma. This includes symptoms as subtle as memory loss and as obvious as unconsciousness.

Classic cerebral concussion manifests as slowly resolving, temporary, reversible neurologic dysfunction such as memory loss, often accompanied by a significant loss of consciousness (more than 5 minutes, less than 6 hours). The CT scan is normal.

Diffuse axonal injury: 

This results in a prolonged comatose state (more than 6 hours). In the milder form, the coma is of 6 to 24 hours duration, and may be associated with long-standing or permanent neurologic or cognitive deficits. A coma of moderate form lasts for more than 24 hours and is associated with a mortality of 20%. The severe form shows brain stem dysfunction with the coma lasting for more than 24 hours or even months, because of the involvement of the reticular activating system.

Diagnosis and Differential Diagnosis

Apart from the history and serial neurologic examinations and a standard  assessment  tool  such  as  the  Glasgow  Coma  Scale (table 2), the radiological examinations are helpful in making a definitive diagnosis. A CT scan of the head is the most important diagnostic test to be performed in patients with neurologic findings after head trauma (Gennarelli and Kotapa 1992; Gorden 1991; Johnson and Lee 1992), and allows rapid and accurate assessment of surgical and nonsurgical lesions in the critically injured patients (Johnson and Lee 1992). Magnetic resonance (MR) imaging is complementary to the evaluation of cerebral head trauma. Many lesions are identified by MR imaging such as cortical contusions, small subdural haematomas and diffuse axonal injuries that may not be seen on CT examinations (Sklar et al. 1992).

Table 2. Glasgow Coma Scale.

Treatment and Prognosis

Patients with head trauma need to be referred to an emergency department, and a neurosurgical consultation is important. All patients known to be unconscious for more than 10 to 15 minutes, or with a skull fracture or a neurologic abnormality, require hospital admission and observation, because the possibility exists of delayed deterioration from expanding mass lesions (Gennarelli and Kotapa 1992).

Depending on the type and severity of head trauma, provision of supplemental oxygen, adequate ventilation, decrease of brain water by intravenous administration of faster-acting hyperosmolar agents (e.g., mannitol), corticosteroids or diuretics, and surgical decompression may be necessary. Appropriate rehabilitation is advisable at a later stage.

A multicentre study revealed that 26% of patients with severe head injury had good recovery, 16% were moderately disabled, and 17% were either severely disabled or vegetative (Gennarelli and Kotapa 1992). A follow-up study also found persistent headache in 79% of the milder cases of head injury, and memory difficulties in 59% (Gennarelli and Kotapa 1992).

Prevention

Safety and health education programmes for the prevention of work-related accidents should be instituted at the enterprise level for workers and management. Preventive measures should be applied to mitigate the occurrence and severity of head injuries due to work-related causes such as falls and transport accidents.

Back

First aid is the immediate care given to victims of accidents before trained medical workers arrive. Its goal is to stop and, if possible, reverse harm. It involves rapid and simple measures such as clearing the air passageway, applying pressure to bleeding wounds or dousing chemical burns to eyes or skin.

The critical factors which shape first aid facilities in a workplace are work-specific risk and availability of definitive medical care. The care of a high-powered saw injury is obviously radically different from that of a chemical inhalation.

From a first aid perspective, a severe thigh wound occurring near a surgical hospital requires little more than proper transport; for the same injury in a rural area eight hours from the nearest medical facility, first aid would include—among other things—debridement, tying off bleeding vessels and administration of tetanus immunoglobulin and antibiotics.

First aid is a fluid concept not only in what (how long, how complex) must be done, but in who can do it. Though a very careful attitude is required, every worker can be trained in the top five or ten do’s and don’ts of first aid. In some situations, immediate action can save life, limb or eyesight. Co-workers of victims should not remain paralyzed while waiting for trained personnel to arrive. Moreover, the “top-ten” list will vary with each workplace and must be taught accordingly.

Importance of First Aid

In cases of cardiac arrest, defibrillation administered within four minutes yields survival rates of 40 to 50%, versus less than 5% if given later. Five hundred thousand people die of cardiac arrest every year in the United States alone. For chemical eye injuries, immediate flushing with water can save eyesight. For spinal cord injuries, correct immobilization can make the difference between full recovery and paralysis. For haemorrhages, the simple application of a fingertip to a bleeding vessel can stop life-threatening blood loss.

Even the most sophisticated medical care in the world often cannot undo the effects of poor first aid.

First Aid in the Context of the GeneralOrganization of Health and Safety

The provision of first aid should always have a direct relationship to general health and safety organization, because first aid itself will not handle more than a small part of workers’ total care. First aid is a part of the total health care for workers. In practice, its application will depend to a large extent on persons present at the time of an accident, whether co-workers or formally trained medical personnel. This immediate intervention must be followed by specialized medical care whenever needed.

First aid and emergency treatment in cases of accident and indisposition of workers at the workplace are listed as an important part of the functions of the occupational health services in the ILO Occupational Health Services Convention (No.  161), Article 5, and the Recommendation of the same name. Both adopted in 1985, they provide for the progressive development of occupational health services for all workers.

Any comprehensive occupational safety and health programme should include first aid, which contributes to minimizing the consequences of accidents and is therefore one of the components of tertiary prevention. There is a continuum leading from the knowledge of the occupational hazards, their prevention, first aid, emergency treatment, further medical care and specialized treatment for reintegration into and readaptation to work. There are important roles that occupational health professionals can play along this continuum.

It is not infrequent that several small incidents or minor accidents take place before a severe accident occurs. Accidents requiring only first aid represent a signal which should be heard and used by the occupational health and safety professionals to guide and promote preventive action.

Relation to Other Health-Related Services

The institutions which may be involved in the organization of first aid and provide assistance following an accident or illness at work include the following:

• the occupational health service of the enterprise itself or other occupational health entities
• other institutions which may provide services, such as: ambulance services; public emergency and rescue services; hospitals, clinics and health centres, both public and private; private physicians; poison centres; civil defence; fire departments; and police.

Each of these institutions has a variety of functions and capabilities, but it must be understood that what applies to one type of institution—say a poison centre—in one country, may not necessarily apply to a poison centre in another country. The employer, in consultation with, for example, the factory physician or outside medical advisers, must ensure that the capabilities and facilities of neighbouring medical institutions are adequate to deal with the injuries expected in the event of serious accidents. This assessment is the basis for deciding which institutions will be entered into the referral plan.

The cooperation of these related services is very important in providing proper first aid, particularly for small enterprises. Many of them may provide advice on the organization of first aid and on planning for emergencies. There are good practices which are very simple and effective; for example, even a shop or a small enterprise may invite the fire brigade to visit its premises. The employer or owner will receive advice on fire prevention, fire control, emergency planning, extinguishers, the first aid box and so on. Conversely, the fire brigade will know the enterprise and will be ready to intervene more rapidly and efficiently.

There are many other institutions which may play a role, such as industrial and trade associations, safety associations, insurance companies, standards organizations, trade unions and other non-governmental organizations. Some of these organizations may be knowledgeable about occupational health and safety and can be a valuable resource in the planning and organization of first aid.

An Organized Approach to First Aid

Organization and planning

First aid cannot be planned in isolation. First aid requires an organized approach involving people, equipment and supplies, facilities, support and arrangements for the removal of victims and non-victims from the site of an accident. Organizing first aid should be a cooperative effort, involving employers, occupational health and public health services, the labour inspectorate, plant managers and relevant non-governmental organizations. Involving workers themselves is essential: they are often the best source on the likelihood of accidents in specific situations.

Whatever the degree of sophistication or the absence of facilities, the sequence of actions to be taken in the case of an unforeseen event must be determined in advance. This must be done taking due account of existing and potential occupational and non-occupational hazards or occurrences, as well as ways of obtaining immediate and appropriate assistance. Situations vary not only with the size of the enterprise but also with its location (in a town or a rural area) and with the development of the health system and of labour legislation at the national level.

As regards the organization of first aid, there are several key variables to be considered:

• type of work and associated level of risk
• potential hazards
• size and layout of the enterprise
• other enterprise characteristics (e.g., configuration)
• availability of other health services.

Type of work and associated level of risk

The risks of injury vary greatly from one enterprise and from one occupation to another. Even within a single enterprise, such as a metalworking firm, different risks exist depending on whether the worker is engaged in the handling and cutting of metal sheets (where cuts are frequent), welding (with the risk of burns and electrocution), the assembly of parts, or metal plating (which has the potential of poisoning and skin injury). The risks associated with one type of work vary according to many other factors, such as the design and age of the machinery used, the maintenance of the equipment, the safety measures applied and their regular control.

The ways in which the type of work or the associated risks influence the organization of first aid have been fully recognized in most legislation concerning first aid. The equipment and supplies required for first aid, or the number of first aid personnel and their training, may vary in accordance with the type of work and the associated risks. Countries use different models for classifying them for the purpose of planning first aid and deciding whether higher or lower requirements are to be set. A distinction is sometimes made between the type of work and the specific potential risks:

• low risk-for example, in offices or shops
• higher risk-for example, in warehouses, farms and in some factories and yards
• specific or unusual risks-for example, in steelmaking (especially when working on furnaces), coking, non-ferrous smelting and processing, forging, foundries; shipbuilding; quarrying, mining or other underground work; work in compressed air and diving operations; construction, lumbering and woodworking; abattoirs and rendering plants; transportation and shipping; most industries involving harmful or dangerous substances.

Potential hazards

Even in enterprises which seem clean and safe, many types of injury can occur. Serious injuries may result from falling, striking against objects or contact with sharp edges or moving vehicles. The specific requirements for first aid will vary depending on whether the following occur:

• falls
• serious cuts, severed limbs
• crushing injuries and entanglements
• high risks of spreading fire and explosions
• intoxication by chemicals at work
• other chemical exposure
• electrocution
• exposure to excessive heat or cold
• lack of oxygen
• exposure to infectious agents, animal bites and stings.

The above is only a general guide. The detailed assessment of the potential risks in the working environment helps greatly to identify the need for first aid.

Size and layout of the enterprise

First aid must be available in every enterprise, regardless of size, taking into account that the frequency rate of accidents is often inversely related to the size of the enterprise.

In larger enterprises, the planning and organization of first aid can be more systematic. This is because individual workshops have distinct functions and the workforce is more specifically deployed than in smaller enterprises. Therefore the equipment, supplies and facilities for first aid, and first aid personnel and their training, can normally be organized more precisely in response to the potential hazards in a large enterprise than in a smaller one. Nevertheless, first aid can also be effectively organized in smaller enterprises.

Countries use different criteria for the planning of first aid in accordance with the size and other characteristics of the enterprise. No general rule can be set. In the United Kingdom, enterprises with fewer than 150 workers and involving low risks, or enterprises with fewer than 50 workers with higher risks, are considered small, and different criteria for the planning of first aid are applied in comparison with enterprises where the number of workers present at work exceeds these limits. In Germany, the approach is different: whenever there are fewer than 20 workers expected at work one set of criteria would apply; if the number of workers exceeds 20, other criteria will be used. In Belgium, one set of criteria applies to industrial enterprises with 20 or fewer workers at work, a second to those with between 20 and 500 workers, and a third to those with 1,000 workers and more.

Other enterprise characteristics

The configuration of the enterprise (i.e., the site or sites where the workers are at work) is important to the planning and organization of first aid. An enterprise might be located at one site or spread over several sites either within a town or region, or even a country. Workers may be assigned to areas away from the enterprise’s central establishment, such as in agriculture, lumbering, construction or other trades. This will influence the provision of equipment and supplies, the number and distribution of first aid personnel, and the means for the rescue of injured workers and their transportation to more specialized medical care.

Some enterprises are temporary or seasonal in nature. This implies that some workplaces exist only temporarily or that in one and the same place of work some functions will be performed only at certain periods of time and may therefore involve different risks. First aid must be available whenever needed, irrespective of the changing situation, and planned accordingly.

In some situations employees of more than one employer work together in joint ventures or in an ad hoc manner such as in building and construction. In