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Occupational disease
Occupational disease, any illness associated with a particular occupation or industry. Such diseases result from a variety of biological, chemical, physical, and psychological factors that are present in the work environment or are otherwise encountered in the course of employment. Occupational medicine is concerned with the effect of all kinds of work on health and the effect of health on a worker's ability and efficiency.
Occupational diseases are essentially preventable and can be ascribed to faulty working conditions. The control of occupational health hazards decreases the incidence of work-related diseases and accidents and improves the health and morale of the work force, leading to decreased absenteeism and increased worker efficiency. In most cases the moral and economic benefits far outweigh the costs of eliminating occupational hazards.
This article discusses general occupational health hazards and the disorders they cause, as well as the role of occupational health services. More detailed information about specific disorders can be found in the articles dealing with human diseases and the structures of the human body, such as cancer; infection; and respiratory disease.
Historical overview
The preindustrial era
The first recorded observation of an occupational disease may be a case of severe lead colic suffered by a worker who extracted metals. It is described in the third book of Epidemics, attributed to Hippocrates, the Greek physician of the 4th century bce. Other early writers also recognized the association between certain disorders and occupations. The Roman scholar Pliny, in the 1st century ce, described mercury poisoning as a disease of slaves because mines contaminated by mercury vapour were considered too unhealthy for Roman citizens and thus were worked only by slaves. In general, however, physicians of antiquity were not concerned with the health of workers.
During the Middle Ages the rise of metalliferous mining in central Europe inspired the German mineralogist Georgius Agricola to make a detailed study of gold-and silver-mining operations. In his De Re Metallica, published posthumously in 1556, Agricola described the primitive methods of ventilation and personal protection in use, common mining accidents and disasters, and such miners' occupational diseases as the "difficulty in breathing and destruction of the lungs" caused by the harmful effects of dust inhalation.
A more comprehensive account of occupational disorders was written by Bernardino Ramazzini, a professor of medicine first at the University of Modena and later at the University of Padua. His De Morbis Artificum Diatriba (1700; Diseases of Workers) contains descriptions of the diseases associated with 54 different occupations, from the mercury poisoning of Venetian mirror makers to the diseases afflicting learned men. Ramazzini believed that a physician must determine the patient's occupation in order to discover the cause of the patient's disorder. He is generally regarded as the father of occupational medicine.
The industrial era
The Industrial Revolution of the 18th century had a profound impact on occupational diseases. Rapid technological progress and industrial growth had led to crowded, unsanitary working and living conditions, with a corresponding rise in the number of accidents and deaths caused by the new machinery and exposure to toxic materials. In 1775 Percivall Pott, a London surgeon, linked the frequent occurrence of scrotal cancer among chimney sweeps to the soot ingrained into their skin by prolonged exposure to flue dusts. Charles Turner Thackrah, a Leeds physician, further advanced the study of occupational medicine in Britain with his The Effects of the Principal Arts, Trades and Professions . . . on Health and Longevity . . . (1831), which described lung diseases caused by dust that commonly afflicted miners and metal grinders. In 1895 Britain introduced a statutory notification system that required medical personnel to report all occurrences of certain diseases to the chief inspector of factories. Other industrial nations followed Britain's lead, and legal provisions for the health of the worker continued to be instituted throughout the 19th and 20th centuries.
The 20th century
Although such classic occupational diseases as lead poisoning and anthrax have declined in incidence in industrialized countries, none have been eradicated. Furthermore, new diseases continue to develop as a result of advances in technology. X rays were discovered in 1895, and 20 years later nearly 100 radiologists were estimated to have died as a result of occupational exposures. Asbestos-related disease was first reported in the first half of the 20th century, and in 1974 hemangiosarcoma, a rare malignant tumour of the liver, was discovered among workers involved in the polymerization of vinyl chloride monomer. Other occupational diseases related to the introduction of industrial processes and materials may well be recognized in the future.
Paralleling the development of new technology and occupational hazards has been the development of occupational health services. No longer concerned primarily with the prevention of industrial accidents and diseases among manual workers, industrial medicine now aims to protect and improve the health of all classes and kinds of workers. In 1950 a joint committee of the International Labour Organisation and the World Health Organization (ILO/WHO) defined the concerns of occupational health as:
the promotion and maintenance of the highest degree of physical, mental and social well-being of workers in all occupations; the prevention among workers of departures from health caused by their working conditions; the protection of workers in their employment from risks resulting from factors adverse to health; the placing and maintenance of the worker in an occupational environment adapted to his physiological equipment and, to summarise, the adaptation of work to man and of each man to his job.
In most countries in the West the responsibility for health and safety at work is placed on the employer, although the government may establish safety standards. Occupational health services are provided as benefits by employers and generally are separate from other community health services. In the former Soviet Union occupational health and hygiene were given high priority and were fully integrated in the general medical care system. In the developing and Third World countries, many of which are undergoing rapid industrialization, the importance of occupational health is increasingly realized. The problems of exposure to occupational hazards, however, are frequently compounded by preexisting malnutrition and a high incidence of infectious disease. Occupational health services in these countries are often most practical and cost-effective, therefore, when combined with primary health care delivery.
Aims and functions of occupational health services
The primary concerns of occupational health services remain those specified by the ILO/WHO in 1950, although work-related diseases are now considered as well as purely occupational diseases. The actual services offered are essentially preventive in nature and are summarized below.
Job placement
People with certain preexisting medical conditions may be at a disadvantage in some jobs. A preemployment health questionnaire or medical examination can be of great value in such cases by determining job unsuitability before training time and expense have been incurred. Job suitability may also need to be regularly monitored in order to assure employee health and ability. Airline pilots, for example, undergo regular medical checkups because a pilot with failing vision or one who suffers from an undetected heart condition that can lead to a heart attack could endanger many lives. The health service can also give valuable advice with regard to alternative employment when a worker is found to be unfit for a particular job.
Safety training
An occupational health service has a responsibility to keep all employees informed about hazards in the workplace. The measures taken to protect employee health should be thoroughly explained so that workers understand the necessity of complying with such irksome or unpleasant restrictions as the wearing of protective clothing and face masks. First aid facilities should be organized and employees instructed about first aid procedures in case of accidental injuries or other emergencies.
Supervision of high-risk groups
Exposure levels considered safe for a young male worker may be hazardous for a pregnant woman (the fetus, especially during the first three months of development, is particularly sensitive to environmental toxic agents). Pregnant women, as well as such other vulnerable groups as the very young, the elderly, and the disabled, therefore require appropriate medical surveillance and advice about specific precautionary measures they can take.
Control of recognized hazards
A complex system of environmental and biological monitoring has been developed for the control of known hazards at work. Occupational health practice is concerned with monitoring the concentration of toxic substances in the environment, determining safe exposure levels, suggesting procedures to limit worker exposure, and monitoring workers for signs of overexposure. Occupational health specialists can also contribute to the prevention of health risks by assisting in the planning and design of new equipment and factories.
Identification of unrecognized hazards
Occupational health services can play a major role in the detection of new health hazards of all types. Clinical observation and study may reveal a causal relationship between patterns of sickness or mortality in groups of workers and their occupational exposure. Examples of hazards identified in this manner include lung and nasal cancer among nickel workers, lung cancer in asbestos workers, and coronary heart disease among workers exposed to carbon disulfide (used in the manufacture of rayon).
Quick, on-site treatment of work injuries and poisonings can prevent complications and aid recovery. Such treatment can also be economically beneficial by saving traveling and waiting time. Furthermore, physicians and nurses who are unfamiliar with their patients' working conditions may keep workers with minor injuries away from work longer than necessary. An occupational treatment service offers opportunities for specialized counseling and health education.
General health education and surveillance
Occupational health services may have to provide general medical care for workers and their families in developing countries with inadequate community health services. Even when general health care is provided elsewhere, an occupational health service can offer an effective and often economically advantageous program of health education and counseling. By advising employees on such topics as smoking, alcohol or drug abuse, exercise, and diet, the occupational health service can improve worker health and efficiency and reduce illness and absenteeism. The health service is also in a position to organize employee health surveillance programs for the early diagnosis of disease.
Disorders due to chemical agents
Hazardous chemicals can act directly on the skin, resulting in local irritation or an allergic reaction, or they may be absorbed through the skin, ingested, or inhaled. In the workplace ingestion of toxic chemicals is usually accidental and most commonly results from handling contaminated food, drink, or cigarettes. Substances that occur as gases, vapours, aerosols, and dusts are the most difficult to control, and most hazardous chemicals are therefore absorbed through the respiratory tract. If inhaled, airborne contaminants act as irritants to the respiratory tract or as systemic poisons. Toxicity in such cases depends on the contaminant's concentration, particle size, and physicochemical properties, particularly its solubility in body fluids. An individual's reaction to any hazard depends primarily on the length, pattern, and concentration of exposure but is also affected by such factors as age, sex, ethnic group, genetic background, nutritional status, coexistent disease, concomitant exposure to other toxic agents, life-style, and history of previous exposure to the agent in question. The wide range of both naturally occurring and synthetic chemical compounds that can give rise to adverse health effects can be roughly organized into four major categories: gases, metals, organic compounds, and dusts.
Gases may act as local irritants to inflame mucous surfaces. Common examples include sulfur dioxide, chlorine, and fluorine, which have pungent odours and can severely irritate the eyes and the respiratory tract. Some gases, such as nitrogen oxides and phosgene, are much more insidious. Victims may be unaware of the danger of exposure because the immediate effects of these gases may be mild and overlooked. Several hours after exposure, however, breathlessness and fatal cardiorespiratory failure due to pulmonary edema (collection of fluid in the lungs) may develop.
Gases that interfere with oxygen supply to the tissues are known as asphyxiants and are of two principal types. Simple asphyxiants are physiologically inert gases that act by diluting atmospheric oxygen. If the concentration of such gases is high enough, hypoxia (deficiency of oxygen reaching the tissues of the body) results. Victims of mild hypoxia may appear to be intoxicated and may even resist rescue attempts. Common examples of simple asphyxiants are methane and carbon dioxide.
In contrast to simple asphyxiants, chemical asphyxiants, such as carbon monoxide and hydrogen sulfide, are highly reactive. They cause a chemical action that either prevents the blood from transporting oxygen to the tissues or interferes with oxygenation in the tissues. For example, carbon monoxide, a frequently encountered gas produced by incomplete combustion, combines with hemoglobin in the blood and reduces its oxygen-carrying capacity. In low concentration carbon monoxide poisoning can cause symptoms of fatigue, headache, nausea, and vomiting, but heavy exposure leads to coma and death. It is especially dangerous because it is both colourless and odourless. Hydrogen sulfide, however, can be recognized by its characteristic smell, suggestive of rotten eggs. It is produced when sulfur compounds decompose and acts by inhibiting the respiratory enzyme cytochrome oxidase, thus giving rise to severe tissue hypoxia. In addition to its asphyxiant properties, hydrogen sulfide also acts as an irritant to the eyes and mucous membranes.
Preventing gas poisoning involves preventing exposure. Workers should never enter enclosed spaces that have suspect atmospheres alone; workplaces should provide adequate ventilation, and air should be regularly tested for contamination. If exposure does occur, treatment involves the removal of the victim from the contaminated atmosphere, artificial respiration, and administration of oxygen or recommended antidotes. Victims exposed to gases with insidious delayed effects should be kept under medical observation for an appropriate period.
Metals and their compounds are among the poisons most commonly encountered in the home and workplace. Even metals essential for life can be toxic if they are present in excessive amounts. Iron, for example, is an essential element and is sometimes given therapeutically; if taken in overdose, however, it can be lethal.
Mercury poisoning, one of the classic occupational diseases, is a representative example of metal poisoning. Exposure to mercury can occur in many situations, including the manufacture of thermometers, explosives, fungicides, drugs, paints, batteries, and various electrical products. The disorders it can cause vary depending on the type of mercury compound and the method of exposure.
Ingestion of mercury salts such as mercuric chloride (corrosive sublimate) leads to nausea, vomiting, and bloody diarrhea. Kidney damage resulting in death may follow in extreme cases. Inhalation or absorption through the skin of mercury vapour causes salivation, loosening of the teeth, and tremor; it also affects the higher centres of the brain, resulting in irritability, loss of memory, depression, anxiety, and other personality changes. This mental deterioration, known as erethism, led to the well-known saying "mad as a hatter," because, in the past, hatters commonly became ill when they used mercury salts to make felt out of rabbit fur. Poisoning with organic mercury compounds (used in fungicides and pesticides) results in permanent neurological damage and can be fatal.
Other hazardous metals commonly encountered in industry include arsenic, beryllium, cadmium, chromium, lead, manganese, nickel, and thallium. Some have been shown to be carcinogenic, including certain compounds of nickel (linked to lung and nasal cancer), chromium (lung cancer), and arsenic (lung and skin cancer).
Organic compounds
The organic compounds that pose the greatest occupational hazards are various aromatic, aliphatic, and halogenated hydrocarbons and the organophosphates, carbamates, organochlorine compounds, and bipyridylium compounds used as pesticides.
Pesticides are used the world over; and, even though precautionary measures (such as using protective clothing and respirators, monitoring contamination of equipment and clothing, keeping workers out of recently sprayed areas, and requiring workers to wash thoroughly after exposure) can be instituted, poisoning not infrequently occurs in agricultural communities. The organophosphates and the generally less toxic carbamates exert their effects by inhibiting cholinesterase, an enzyme that prevents stimulation from becoming too intense or prolonged by destroying the acetylcholine involved in the transmission of impulses in the autonomic nervous system. Cholinesterase inhibitors allow the accumulation of acetylcholine, causing symptoms related to parasympathetic overactivity, such as chest tightness, wheezing, blurring of vision, vomiting, diarrhea, abdominal pain, and in severe cases respiratory paralysis. Atropine and certain oximes counteract their effects.
Paraquat and diquat, the bipyridylium compounds, are deadly if ingested. Skin contact or inhalation of a concentrate of paraquat can cause fatal lung damage. Because no specific antidote is known, treatment consists of minimizing the body's absorption of the poison.
The organochlorine compounds, such as DDT, are being progressively phased out of use. Because they are fat-soluble and very stable, they accumulate and remain in the fatty tissues of the body for prolonged periods. Symptoms of poisoning include nausea, irritability, weakness, muscle tremors, and convulsions. There is no specific antidote.
Other groups of pesticides that are used less frequently or are less hazardous include the organomercury compounds (see above Metals); the dinitro and arsenic compounds; and nicotine.
Hydrocarbons are used industrially in the derivation of other compounds and in solvents, degreasing agents, refrigerants, fire extinguishers, dry cleaning agents, paint removers, and other products. Many are volatile and can be absorbed by inhalation; some are fat-soluble and can be readily absorbed following spills on the skin.
Gasoline, fuel oils, and other petroleum products are common examples of aliphatic hydrocarbons. If they are ingested or inhaled, dizziness, weakness, nausea, or irritation of the lungs may follow. In very severe cases victims may become unconscious or experience convulsions. Direct contact causes skin irritation and dryness. Prolonged exposure to certain petroleum oils may result in skin cancer.
The aromatic hydrocarbon benzene provides the basis for the synthesis of many other organic compounds. It is rapidly absorbed following inhalation or skin contact. Symptoms from mild exposure include dizziness, headache, euphoria, confusion, and nausea. Long-term exposure may be followed by bone marrow depression, anemia, spontaneous bleeding, and leukemia. Several aromatic hydrocarbons are known to be carcinogens. Particularly hazardous are naphthylamine, benzidine, and 4-amino diphenyl, which cause bladder cancer. Previously used in the synthetic dye, synthetic rubber, cable-making, and chemical industries, they have been banned in a number of countries.
When aliphatic and aromatic hydrocarbons have hydrogen atoms in their structure replaced by halogens (often chlorine), they are known as halogenated hydrocarbons. In general, increasing the chlorination of aliphatic hydrocarbons increases their toxicity, while the reverse is true of the aromatic series. Many chlorinated hydrocarbons, including chloroform and trichloroethylene, act as depressants on the central nervous system, producing anesthetic or narcotic effects that may be abused. Occupational exposure to many solvents may act synergistically with alcohol, resulting in more damage than either agent could produce on its own. Some halogenated hydrocarbons cause extensive disorders in addition to their common narcotic effect. Inhaling or ingesting the solvent carbon tetrachloride, for example, leads to liver damage; and exposure to vinyl chloride causes Raynaud's phenomenon (spasms in the small arteries that cause the extremities to become pale and cold, as well as painful), necrosis of the small bones of the hand, liver damage, and a rare, highly malignant tumour of the liver.
Workers exposed to hydrocarbons should wear protective clothing or masks when appropriate, moderate alcohol consumption, and verify that work areas are well ventilated and that recommended exposure levels are not exceeded.
The inhalation of a variety of dusts is responsible for a number of lung and respiratory disorders, whose symptoms and severity depend on the composition and size of the dust particle, the amount of dust inhaled, and the length of exposure. The lung diseases known as the pneumoconioses result when certain inhaled mineral dusts are deposited in the lungs, where they cause a chronic fibrotic reaction that leads to decreasing capacity for exercise and increasing breathlessness, cough, and respiratory difficulty. No specific treatment is known, but as with all respiratory disorders patients are urged to quit smoking, which aggravates the condition. Suggested measures for limiting exposure include using water and exhaust ventilation to lower dust levels and requiring workers to wear respirators or protective clothing, but such procedures are not always feasible. Coal worker's pneumoconiosis, silicosis, and asbestosis are the most common pneumoconioses.
As its name suggests, coal worker's pneumoconiosis (also known as black lung) occurs most frequently among coal miners and workers involved in the transporting or processing of coal. It is generally benign in its early stages, but after a variable number of years of exposure to coal dust, progressive massive fibrosis may develop, ending in cardiorespiratory failure. Miners and quarry workers are the people most likely to suffer from silicosis. Because silica is found in many rocks and is used in a variety of industries, workers involved in stonecutting, grinding, drilling, foundry work, sandblasting, pottery making, and the manufacture of abrasives are also at risk. Silicosis is an aggressive form of pulmonary fibrosis that speeds the progress of tuberculosis. Routine chest X rays can aid early diagnosis by revealing abnormal shadowing. Asbestosis is more difficult to detect in the early stages because chest X rays usually reveal little until the disease is advanced. From onset asbestosis progresses more rapidly than the other pneumoconioses and can result from relatively low exposure. Asbestos is the general term for a number of fibrous silicates that are used primarily in various fireproofing, insulation, and cement products. In addition to pulmonary fibrosis, inhaling asbestos fibres has also been shown to cause lung and other cancers.
Prolonged exposure to certain plant and animal dusts can cause asthma, even in people without a predisposition for allergies. Specific hazards include dusts from flour, grains, and wood and wood products. Cotton workers and others handling hemp or flax may develop a condition known as byssinosis, similar to asthma. The group of diseases known as farmer's lung, malt worker's lung, bird fancier's lung, and so forth are caused by an allergic inflammatory reaction to the fungal spores present in moldy hay or barley, bird droppings, feathers, and a variety of other organic materials. Symptoms initially resemble those of influenza or pneumonia, but repeated episodes eventually lead to pulmonary fibrosis with chronic respiratory impairment. The only treatment for these disorders is avoiding exposure to the dusts.


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TELEVISION on the JOB (Feb, 1947)
TELEVISION on the JOB
It extends human vision beneath seas, into furnaces and throughout factories.
TELEVISION is adding overalls to its dress clothes. Its sleeves are rolled-it is ready to go to work!
To most of us, television has been a promise of armchair entertainment—a chance to have choice seats at boxing bouts, football games, news events and stage plays without budging from the budget or the living room. That phase of television is here, but television's future goes far beyond the mere prospects of animated quiz shows and soap operas you can see.
Television, like radio, is a versatile tool. A relatively small percentage of the radio waves that flash around the earth today carry music and comedy to our loudspeakers. Most of them have more important missions. Radio helps us go places and do business. Without it, large-scale scheduled air travel would be impossible, sea travel would be slowed, crime prevention hampered, news coverage cut down, and international business and diplomacy limited.
Television likewise means much more to us than an amusing accompaniment for radio's sound. Its workaday uses are even more dramatic than its role as an entertainer. I found that out when I got a firsthand look into television's future at the large
modern laboratories of the Radio Corporation of America at Princeton, N. J. There I put questions to Dr.. Vladimir K. Zworykin, director of the laboratories' program of electronic research—one of the men who helped raise television from its flickering beginnings to its present status.
Getting Dr. Zworykin to talk about television was not a hard assignment. He thinks it, dreams it, lives it, and talks about it with parental love.
"Television," he explained, after he had shown me his laboratory, "is an extension of our sight. It gives us a simple means of getting eyewitness views of things happening in places too small, too distant, or far too dangerous for the average person to observe. Properly applied, television can show us many things that we have never seen before. It can open up whole new frontiers of research and knowledge.
"Undersea exploration is an excellent example. Few divers can descend more than 200 feet. Television, however, can put our eyes there without risk to our bodies. By installing a television camera in a thick-walled metal bathysphere, lowered from a survey ship, the deepest ocean floor can be explored safely and for hours at a time by skilled observers seated comfortably in front of a direct-wire television viewer on deck— or on dry land, for that matter, if the television signals from the camera are radio-relayed from ship to shore."
As Dr. Zworykin enlarged on his idea I realized that the construction of such a television bathysphere would present no great problems. It could be similar in design to the diving ball that Dr. William Beebe used in his undersea observations. With thicker walls to withstand greater pressures, it would otherwise be simpler, since a television camera, unlike a man, requires no oxygen and would be unaffected by the near-zero temperatures 600 feet under.
Since scenes have been televised from the dim light of a candle, illumination would not be difficult. The modern television camera using the new Image Orthicon tube, another Zworykin-guided development, is as sensitive to light as the human eye, so floodlights for underwater television exploration would have to be no brighter ,than those required for human observation. The bathysphere could be lowered by cable, while remotely controlled motors built into a supporting gimbal could turn and tilt its "eye" to scan the surroundings. The bathysphere could be used to aid under-water salvage, guide the placing of drilling gear for undersea oil wells, assist in submarine rescues, and, perhaps, even test the myth of lost Atlantis. The depths that could be plumbed would be limited only by the strength of the sphere's metal shell.
Similarly, according to Dr. Zworykin television cameras can give us close-up views of what goes on within chemical reaction chambers, inside fiery furnaces and behind the thick lead walls that surround atomic-fission experiments. It provides us with a third eye that is unaffected by lethal fumes, heat or radiations.
What actually goes on inside smelting furnaces and glass furnaces is still pretty much anybody's guess. The heat is so great that temperatures must be measured from a distance with optical pyrometers, and quick glimpses through jet-black goggles are the only observations possible. Any closer view would sear the flesh, blind the eyes. Television cameras at strategic spots inside the furnaces could flash pictures of the fiery mass to a viewer in the office of the plant engineer. He could watch the process from beginning to end with no more bother than switching Ms viewer from one camera to another. He could literally "walk around" inside the furnace. The glow from the molten metal or glass would provide more than enough illumination, and liquid-cooled jackets would protect the cameras. Dr. Zworykin also envisions television as a super-supervisor in the huge factory tomorrow morrow. Television cameras set up in the various departments of a manufacturing plant would allow one man in a central viewing room to watch, control and safe-guard the entire plant's activities. Rows of television viewers would show him exactly what was happening at nerve centers of the factory. His master control room would be an industrial equivalent of the CIC (Combat Intelligence Center) rooms that coordinated our fighting forces along the different fronts during the war. Such a system would speed production and safeguard life and property.
A similar setup on a smaller scale could be used to control the flow of automobile assembly lines. At present, it requires the services of a corps of men to supervise the 25 miles or more of subassembly and main assembly lines that snake their way through most big automobile plants. Television cameras set up at the feeder lines and along the length of the main assembly line and wired to viewers in the main supervisor's office could bring the entire problem under his eyes.
Television may well change our whole concept of educational techniques, Dr. Zworykin believes. This is particularly true in medicine, where a student's view of an operation consists of what he can see from his seat high in- the operating-room amphitheater. Television, however, can give him a surgeon's-eye view of the whole proceedings. A television camera mounted in the cluster of lights over the operating table and wired to screens in classrooms would not only give each student a close-up of even the most delicate operation but would allow hundreds of students, instead of a few, to watch the demonstration. If put on the air an operation could be witnessed by students in medical schools all over the country wherever television was available. Long-distance diagnosis is another medical possibility. With the aid of television, a doctor and his patient could take full advantage of the knowledge and skill of a specialist a thousand miles away. Public health doctors could make actual television visits to health clinics in outlying districts. Special health lectures could be delivered simultaneously to widely scattered groups. There is no reason why students some day will not get first-hand televised looks at the moon and stars through the giant Palomar telescope, watch important experiments in progress at the world's great research centers, sit in on the actual proceedings at international conferences, or "attend" any of the firsts in science, exploration and the arts. Famous lecturers and educators could be seen and heard simultaneously in schools all over the country.
Television as a teaching aid was dramatically demonstrated in New York City during the war when first aid and fire-bomb-fighting methods were explained to the city's volunteer air-raid wardens via the television camera. Viewers set up at air-raid posts throughout the city made it possible. for a single group of civilian-defense experts to demonstrate air-raid procedures to more wardens than ever could have been jammed into the city's largest auditorium. And what is more to the point, every warden had a close-up of the demonstration.
I asked Dr. Zworykin if he thought it would be possible to equip news reporters with lightweight television cameras that would allow them to broadcast on-the-spot views of accidents, fires, train wrecks and similar news events. As an answer he showed me the compact, lightweight television camera that has been developed for use in a guided rocket. Weighing only 34 pounds, and no larger than a suitcase, it may well be the forerunner of the newscaster's "walkie lookie." It would have to be changed only slightly. Its compact transmitter and power supply, stowed in the reporter's car, would transmit the scene being: televised to a main broadcasting station. There a picture editor, seated before a bank of viewers showing the individual pickups from perhaps a dozen reporters on their beats, could select the events he desired and rebroadcast them to the station's television public.
Several department stores are experimenting with direct-wire television as a means of displaying merchandise to customers. Fashion shows, displays and special [ skits to demonstrate kitchen and garden equipment are televised and piped to view-ers placed in the store's windows and at eye-catching spots around the store. sales test run by one large Eastern department store a poll of the customers showed that nine out of 10 felt television was an aid to their shopping.
Television billboards are the latest ad-vertising wrinkle. The plan, conceived by a Boston, Mass., outdoor advertising firm, calls for a network of large outdoor screens to display television sales programs broadcast by a central station. Set up on roof tops and on the sides of buildings, the television billboards will offer a variety of entertain- I ment interspersed with commercials.
A New York bank is considering installing a direct-wire television system to speed up and simplify the identification of customers. A viewer at each teller's counter connected to a camera at the identification-card files will allow him to verify signatures and bank balances without leaving his window. A similar network for the nation's police forces would speed identification of criminals by photos and fingerprints.
New developments still in the laboratory—such things as three-dimensional and full-color pictures — will extend television uses even further, Dr. Zworykin believes. Full-color television alone, for example, will greatly simplify the accurate matching of colors in the paint, dye and textile industries.
In the meantime, television as we know it today can go far to help industry solve its problems.

subset: commoncrawl


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Are you up to snuff with S84 and OSHA?
Check your safety systems liability at the door. Choosing to ignore S84 standards could put your company on a collision course with OSHA and consequently open you up to criminal liability.
ith the introduction of ISA-S84.01, "Application of Safety Instrumented Systems for the Process Industries," in 1996, the safety instrumented systems (emergency shutdown systems, ESD, interlocks, etc.) landscape changed forever. For the first time we had an industry-wide consensus standard for these types of systems. This standard was also unique because of the large number of companies and other groups that participated in the process and the length of time it took to develop it (~12 years).
With the approval of the new IEC 61511 based on ANSI/ISA-84.00.01, "Functional safety: Safety Instrumented Systems for the Process Industry Sector," in September 2004, the playing field for safety instrumented systems (SIS) is again changing. We now have a standard with an international flavor that covers the whole safety lifecycle with additional requirements and certainly additional documentation requirements.
The new ANSI/ISA-84.00.01 is identical to the IEC 61511 standard with the exception of the addition of a grandfather clause. The new clause is virtually identical to the OSHA 1910.119 grandfather clause with a few exceptions. For example the term "existing equipment" has been replaced with "existing SIS", the word "employer" has been changed to "owner/operator" and the addition of a reference to ISA S84-1996 as a prior good practice are some of the most notable differences.
Let's Discuss the Options
What can companies do in regards to implementing ANSI/ISA-84.00.01? Let's discuss the options. Note however, that to simplify things, the ANSI/ISA-84 standard will be referred to as S84 with indication as to whether the new or old standard is being referred to.
At this time there are four main standards that affect process industry safety instrumented systems. These are ANSI/ISA-S84.01-1996, ANSI/ISA-S84.00.01-2004, IEC-61511-2004, "Functional safety: Safety Instrumented Systems for the process industry sector" and IEC-61508-1998—2000, "Functional safety of electrical/electronic/ programmable electronic safety-related systems." In the scheme of things, ISA-S84.01-1996, ANSI/ISA 84.00.01-2004 and IEC-61511-2004 affect user and system integrator of user systems while IEC-61508-1998—2000 affects manufacturers. While IEC 61508 in the process sector is considered a manufacturer's standard, there are a few instances where 61508 may be applied by the user through references from S84-2004 or IEC 61511.
The question often arises as to whether a company is required to meet the S84 standard. The short answer is No. However, that being said, in 2000 a letter from OSHA to the ISA stated that OSHA acknowledged S84-1996 as a "recognized and generally accepted engineering practice" for safety instrumented systems and that meeting the requirements of S84 for those aspects of OSHA 1910.119 Process Safety Management regulation that S84 covered, met the requirements of 1910.119. The EPA RMP regulations have similar requirements. A similar letter has been requested by ISA from OSHA for the new ANSI/ISA 84.00.01-2004 standard. These letters put companies that want to follow their own standards in the position of justifying that their standards are equivalent or better than S84 if put to the task.
So what options do companies have? There are basically four options: grandfather, meet S84-2004, meet equivalent company standards, or ignore the standards.
Wait Just a Minute Grandpa
One of the first things to raise its head when a company is looking into S84 is "Can we grandfather our systems?" After all, management might say "we've had these systems for a long time and nothing has gone wrong." Many times this is a typical knee-jerk economic response by management reacting to the perceived cost of bringing systems in to compliance with S84 and OSHA. This attitude is often based on a misconception of what it takes to grandfather systems.
The ability to grandfather a safety instrumented system is rooted in S84's grandfather clause which, in turn, is rooted in OSHA 1910.119's grandfather clause. While the wording of these grandfather clauses is slightly different, the intent is the same.
The ANSI/ISA-84.00.01 grandfather clause states: "For existing SIS designed and constructed in accordance with codes, standards, or practices prior to the issue of this standard (e.g., ANSI/ISA-84.01-1996), the owner/operator shall determine and document that the equipment is designed, maintained, inspected, tested and operating in a safe manner."
"A company has basically four options: grandfather, meet S84-2004, meet equivalent company standards, or ignore the standards."
The next question that usually comes up is: "How do I do the grandfathering process?" Currently, there is not much guidance on how its done. Some companies have third parties do it for them, which can provide an independent review.
The S84 committee is working on a S84 guideline technical report, which, among other things, will provide some guidance on grandfathering. There are several examples of grandfathering methods provided by various companies in the draft S84 guideline. They are primarily a checklist-based evaluation against some properties of the S84 standard (level of risk involved, separation, independence, testing, management of change, etc.) or evaluation of meeting company standards at the time of installation. If a company had strong safety instrumented system standards at the design and construction of the SIS, then it may be prudent to verify that the grandfathered system meets those standards and/or the key requirements of S84. On the other hand, a company with less stringent company standards may want to move on to the next step meeting the standard.
Even if a system has been grandfathered, it must still meet the requirements of OSHA 1910.119 which include testing, training, mechanical integrity, and management of change. There is also the matter of making changes in grandfathered systems and at what level of change triggers a requirement to meet the latest standard. Change in kind generally does not trigger an upgrade, but past that it can get a bit murky.
Standards Complex, Yet Simple
The standards are not rocket science but are somewhat complicated and detailed. Some areas can be as clear as mud even for the experts, so meeting the standards is both simple and difficult at the same time. Meeting the standards requires a dedication of resources (people, time, and in some cases require new equipment) to implement the standard's safety lifecycle. One of the primary drags on the process is the lack of in-depth knowledge of the standards and a thorough grasp on the methods needed to meet them. In days past, companies would have dedicated standards experts well-schooled in their implementation. These days many companies have done away with such experts to cut costs. So many times, properly implementing the standard basically comes down to developing the expertise in-house, employing outside expertise, or using a combination of the two.
A Tough Row to Hoe
If you wish to roll your own, there are training courses available from ISA and from firms that specialize in safety system work. But even with training, it can be an uphill row to hoe. It is easy to become a member of the S84 committee; all you need do is to sign up. There are a multitude of technical papers out there on safety systems, but they vary widely in useful content. There are a few books out there on the subject (see the reference section) and one can expect more to come in the near future. Many companies that wish to do it themselves often hire firms or consultants that specialize in this area for a few projects and learn from them before going it alone. This is neither a sink-or-swim endeavor, nor work for amateurs.
Many companies simply do not have the resources to do everything on their own and that leads them to hire outside contractors to do safety system work. This does not get them off the hook for everything though, as things like risk assessment can only be facilitated, but not determined by an outside firm.
Many companies farm out specialized areas such as SIL verification and quantitative analysis. There are certainly a number of companies that specialize in safety systems and provide a range of services to fit the clients needs. There are other firms where safety systems are not their specialty but provide this kind of work as part of a broader offering of engineering services.
Although many companies can provide quality safety system work, there are others whose expertise or quality may be found lacking. Unfortunately, the process is often so new and different one can easily be overwhelmed—not only by the good stuff but by smoke and mirrors as well. If you plan to use a consultant to provide some of your safety system work, pick your contractor well. Quality work can provide a safer plant and many times cut project costs too.
Home-Grown Standards
The use of your own company standards is a valid method of meeting the requirements of "recognized and generally accepted engineering practice" in OSHA 1910.119. The advantage of this is that you don't have to change how you are doing things. The disadvantage is that in practice the standard that your company standards will be held against is the S84 standard, both in technical merit and as industry practice. For existing company standards this may make some sense if the standards have a strong base but for loosely standardized companies, it makes more sense to move on to S84-2004.
Certain less enlightened companies may choose to ignore the standards. Others, perhaps are simply unaware of the standards (which is not an valid excuse no matter what anyone says). This can lead such companies in a collision course with OSHA. Even it you are not covered by OSHA 1910.119 PSM, the General Duty clause may get you. The new standards provide OSHA with a much firmer ground for citations. Unfortunately, many of these same companies are same ones that are more likely to have substandard safety systems. Consciously ignoring S84 or equivalent can open a company up to criminal liability. It also may be grounds for a judgment of gross negligence. Remember that workman's compensation protection laws may not protect a company from being sued directly in some states.
Help Is On the Way
While this can be confusing and a daunting task at first, there is some help on the way from the S84 committee. The committee has been hard at work on guidelines to help the user of the S84 standard. One of the major ones is a guideline for the S84 standard itself, which is getting close to a committee draft vote.
Others areas that the committee is working on is safety bus, burner management systems, fire and gas and electromagnetic compatibility. If you have any interest in these areas, the S84 committee can always use more participation in these areas and others that will develop in the future. There are also existing ISA technical reports on SIL verification and testing available (see the references). The future of SIS standards is one of more thorough, clear definition as the S84 and the international standards continue to evolve (you didn't think that this was the end of it, did you?).
The S84 committee will be issuing technical reports in the future which will help clarify and assist the user in implementing safety instrumented systems. It is anticipated that OSHA will issue a letter in the near future regarding the new S84, which will further cement the standards status as a national standard and as "recognized and generally accepted engineering practice" for OSHA 1901.119.
1. Guidelines for Safe Automation of Chemical Processes, AIChemE Center for Chemical Process Safety, 1993, ISBN: 0-8169-0554-1.
2. Safety Shutdown Systems: Design, Analysis and Justification, Paul Gruhn, P.E. and Harry L. Cheddie, P.E., ISA,1998, ISBN: 1-55617-665-1
3. Control Systems Safety Evaluation & Reliability, 2nd ed , William M. Goble, ISA, 1998, ISBN: 1-55617-636-8.
4. Safety Integrity Level Selection, Systematic Methods Including Layer of Protection Analysis, Ed Marszal and Dr. Eric Scharpf, ISA, 2002, ISBN: 1-55617-777-1
5. Safety Instrumented Systems Verification Practical Probabilistic Calculations, William M. Goble and Harry Cheddie, ISA, Available 2005, ISBN: 1-556717-909-X.
6. Guidelines for the Safe and Reliable Protection of Chemical Processes, Angela Summers, AIChemE CCPS, Available Summer 2005.
7. Reliability, Maintainability and Risk: Practical Methods for Engineers, David J. Smith, Butterworth-Heinemann, 2001.
8. ISA TR84.00.02 "Safety Instrumented Function (SIF) Safety Integrity Level (SIL) Evaluation Techniques, Part 1-5", ISA,2002.
9. ISA TR84.00.03 "Guidance for Testing of Process Sector Safety Instrumented Functions (SIF) Implemented as or within Safety Instrumented Systems", ISA, 2002.
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Maybe one of the estate's cheeky sheep has run off with it! So we'll ask a farmer to keep an eye open but in the mean time please use the website's navigation to find what you were looking for.


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Nighttime burnouts have been known to disappoint photographers. All the smokey goodness generally requires daylight to be properly appreciated. Unless, of course, you're watching through an infrared camera.
This rascally Australian pickup truck (or "ute" to use their vernacular) was tracked and recorded by a Queensland police helicopter as part of increased "anti-hooning" law enforcement efforts.
While the driver may have thought he'd escape prying eyes under the cover of darkness, the heat from the tires and engine make the truck hard to miss — and pretty damn fun to watch.


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He Is Holy: 2019 National Conference
God is holy, and we're not. In fact, He's so holy, His unmediated presence is lethal. Even angels hide their faces and cry, "Holy, holy, holy!" And yet, this holy God has redeemed a people for Himself and …Read More
Press On: 2018 Regional Conference
The Apostle Paul suffered rejection, beatings, imprisonment, and ultimately death as he fulfilled his ministry. Yet he did not become discouraged. Confident in the sufficiency of Christ, Paul found joy even in his trials. Writing from prison, he exhorted the …Read More
Awakening: 2018 National Conference
The fundamental problems facing our society are spiritual in nature. Unconverted people will produce a culture that is opposed to our Creator. Believers who have temporarily lost their zeal for Christ will not be effective ambassadors of Him. The only …Read More
Luther Today: 2017 Regional Conference
We can learn much from Martin Luther and his uncompromising advocacy of the gospel. On August 11, 2017, Ligonier Ministries hosted a regional conference in Wittenberg, Germany, "Luther Today." Our featured speakers were Dr. W. Robert Godfrey, Dr. Steven J …Read More
The Next 500 Years: 2017 National Conference
The same God who brought the Reformation in the sixteenth century is still at work today. His plan has not changed, and what He has purposed for His glory and our good will be accomplished. On March 9-11, 2017, Ligonier …Read More
The Dawn of the Reformation: 2016 Regional Conference
On October 28-29, 2016, we hosted our regional conference "The Dawn of the Reformation" in Lancaster, PA. Drs. Albert Mohler, Stephen Nichols, R.C. Sproul, and Derek Thomas were present to explore the lessons of the Reformation and their continual …Read More
The Dawn of the Reformation: 2016 Fall Conference at Reformation Bible College
On September 16-17, 2016, we hosted our fall conference "The Dawn of the Reformation." Drs. Albert Mohler, Stephen Nichols, R.C. Sproul, and R.C. Sproul, Jr., were present to explore the lessons of the Reformation and their continual relevance …Read More
The Gospel: 2016 National Conference
In 2 Peter 1:16, the Apostle tells us that he and the other Apostles "did not follow cleverly devised myths" when they proclaimed "the power and coming" of Christ Jesus. Rather, the Apostles were "eyewitnesses of his majesty." These …Read More
Overcoming the World: 2014 West Coast Conference
As has been true in every generation, the church today faces many challenges from the world. The intellectual and moral opposition that we face can seem overwhelming at times, which is why we need to remember that Christ has already …Read More
Overcoming the World: 2014 National Conference
As has been true in every generation, the church today faces many challenges from the world. The intellectual and moral opposition that we face can seem overwhelming at times, which is why we need to remember that Christ has already …Read More
The Christian Mind: 2012 National Conference
One of the things most alarming about today's culture is the way in which evangelicals are responding to attacks. Gone are the days, it seems at times, when believers devoted themselves to thinking deeply about the world in order …Read More
Being a Christian in a Post-Christian Culture: 2010 Washington, D.C. Conference
Thabiti Anyabwile, W. Robert Godfrey, Albert Mohler, Burk Parsons, R.C. Sproul Jr., and R.C. Sproul came together at Ligonier Ministries' 2010 Washington, D.C. Conference in an effort to help believers learn how to live out the implications …Read More
Tough Questions Christians Face: 2010 National Conference
Christ has redeemed us to be a light that directs others to Him. Fulfilling this call requires us to be able to deal with the most difficult questions asked about the Christian faith. If we are unprepared to face the …Read More
The Holiness of God: 2009 National Conference
The holiness of God has been obscured, and, consequently, the church's doctrine and ethics have been tarnished. Entertainment has replaced worship in many places, the Gospel is misunderstood and neglected, and the church assimilates itself to the culture instead of …Read More
Together for the Gospel 2008
Celebrate the glorious gospel of our Lord Jesus Christ and its centrality to the task of faithful, biblical pastoring at the 2008 Together for the Gospel conference.Read More
Albert Mohler
Dr. R. Albert Mohler Jr. is president and Joseph Emerson Brown Professor of Christian Theology at The Southern Baptist Theological Seminary in Louisville, Ky. He is host of The Briefing and author of many books, including We Cannot Be Silent. He is on Twitter @AlbertMohler.


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Drawing Galaxy is not your average platform game. Touch the screen to draw a planet with 360 degree gravity and then walk around it! Walk on top of your drawing, on the side of it - even upside down! You can draw anything, but watch out for the evil comets that will stop you on your quest to get to the goal. It may seem simple at first, but with 100 levels to beat, it's going to get complicated! And with a custom level creator, the fun is just getting started!
Only registered members can share their thoughts. So come on! Join the community today (totally free - or sign in with your social account on the right) and join in the conversation.
This was designed as a promotional screenshot for the iTunes store. It says about how there is a level editor.


text: Division of Institutional Advancement Welcome to the Division of Institutional Advancement. We embrace the opportunity to work with you in helping to provide higher educational opportunities to traditionally underserved students in a multi-lingual, multi-cultural learning environment. As a partner in our shared goals there are many ways to support Hostos, now and in the future, with gifts that will "keep on giving". Hostos has experienced a wonderful growth since its inception in 1968 and we welcome your generosity in our continued expansion. Explore this site, read why others have come forward, and join us in our mission.