CHAPTER IX
INDUSTRIAL HYGIENE
GENERAL CONSIDERATION
Definition
That branch of hygiene dealing with industries is of very great importance. This will be readily recognized when we consider that practically the entire population is involved in some sort of gainful occupation.
Industrial hygiene is concerned in creating conditions in industry which will prevent accidents, promote public and personal health by eliminating adverse influences, and in creating environmental conditions which will prolong the worker’s life by improving the conditions under which he labors. Public health, mortality and morbidity are influenced more by the environmental conditions in the occupations than by any other factor in human life. At least two-thirds of the entire human life is spent in some occupation and the danger of life, limb and health is well known to all.
The various industries differ largely in their effects upon the workers, the mortality in some being greater than in others; accidents are more numerous in some than others, some occupations being more hazardous. Some dis-eases occur more frequently in certain occupations. The environment may necessitate a greater adaptation in one part of the body than in another; a very dusty work, for example, will affect the respiratory tract while another occupation will affect a different part of the body.
Effect of Occupation upon Health
It is obvious that occupations have a certain effect upon the adaptative processes of the body as well as producing traumatic conditions from accidents, which result in total or partial disability, sudden death, or acute or chronic conditions from poisoning for example. In the industries there may be such adverse environments as to draw so heavily upon the adaptative forces that the body will be reduced to a greatly weakened state. The personal health of the individual enters as a conditioning factor, as well as do his peculiarities and personal weaknesses.
Personal Factors
The individual with low vitality, poor nutrition and poor elimination will be affected to a greater extent in some occupations than in others. The person with a subluxation at lung place, lessening the resistance of the tissues in this zone, will find that an occupation which necessitates breathing air laden with dust will affect the lungs because of their already weakened condition. Many accidents which jeopardize the health and life of workers result from carelessness or from a lack of knowledge about the devices employed.
Choice of Occupation
Great care should be exercised in the choice of an occupation. This should not be left to chance nor to the ignorant fancy of the youth. The occupations which will best suit the idiosyncrasies of the individual both mentally and physically should be selected. Many lives are shortened because of the unwise choice of occupation. The individual with defective lungs should not select a dusty trade, nor the physically weak person a trade which requires an enormous amount of muscular strength. In other words, a trade should be carefully selected with a view to the weak and strong points of the individual.
In this question of a choice in employment the sex should be taken into consideration. While there are many occupations in which women are as competent or more competent than men, yet there are several factors to be weighed. Taken as a general rule, women are not as strong physically as men. There are some occupations which have a very detrimental effect upon the reproductive organs. Statistics show that women are more easily affected by industrial poisons than men. Congestion of the reproductive organs during menstruation is increased and if women are compelled to work at certain occupations during this menstrual period, they will certainly find it detrimental to their health.
It is a recognized fact, according to many authorities on the subject, that there is a larger percentage of abortions and miscarriages among women in industries than among women in domestic life. The infant mortality is also very much higher. Many abortions and miscarriages result from the effects of industrial poisoning, as well as from heavy and continuous work.
Effect of Labor upon Children
The most injurious effects from occupation are those upon children since they are more susceptible to the ill effects than adults. The child should have every advantage for the development of all parts of his body that there may be no interference with its proper growth. Attention should be given to his mental and moral development. These things can not receive proper attention if the child is forced to labor under adverse conditions just at the time when the body is developing.
Many occupations are such that curvatures of the spine are produced and different parts of the body overtaxed. Child labor should be prohibited. There is no labor so expensive to our country as child labor. If our children are not given an opportunity to develop physically, mentally and morally, we will suffer in citizenship in the next generation. There is bound to be a deterioration from such procedure.
The organs of the child are peculiarly susceptible to the effects of overwork and fatigue; the entire body is in the process of development and its development may be retarded and its growth seriously hindered. It is a most excellent thing to keep the child employed and active, but there certainly should be a means of protecting him from the avarice and greed of heartless employers. The best way to do this is to keep him out of gainful employment until there has been sufficient physical development to insure against overtaxing the young body.
Place of Work
The influence of the occupation upon health will be governed not only by the character of the work, but also by the environment in which the work is performed. Whether it is indoor or outdoor work, whether it is an active or sedentary occupation, and whether there are extremes in the temperature, humidity, air pressure or light, or whether the work is on the surface or below it as in mines, are all factors. The position of the worker, the length of the working hours, the physical, mental and nervous strain all have a bearing on health. Outdoor work is preferred, especially for those who are inclined to pulmonary or respiratory disorders, because of the difference in the purity of the air. Outdoor workers suffer less from fatigue and their mortality rate is lower.
Effect of Posture
Posture of the workman is not without its effect upon the health and its bearing upon industrial hygiene is very important. There are many conditions that have their beginning in the occupation, such as faulty development of different parts of the body, curvatures of the spine, and especially those which are adaptative. Many subluxations are produced by posture assumed during long hours of work. In analyzing such cases chiropractically, the history of the occupation and the posture assumed should be carefully considered so that in adjusting the subluxated vertebrae there may be no opposition to the adaptative processes of Innate Intelligence in her endeavor to compensate for the faulty posture.
Sedentary occupations such as typing, bookkeeping, shoe-making, engraving and tailoring result in lack of muscular activity and produce characteristic occupational disorders and deformities. It is not natural for an individual to remain in any one posture for the greater part of the day. Innate needs to have the body more or less active so that the proper adaptative processes can be carried on within the body.
Sitting constantly at a desk will create a tendency to stooped shoulders and thus cramp the respiratory organs. The result will be a lack of proper oxygenation of the blood which will have its effect upon the metabolic processes of the body. There will be a sluggishness of the liver and other vital organs, and a tendency to anemia, constipation, general lack of muscular tone and low vitality.
Active occupations exercise the natural processes of the body and create a necessity for the action of Innate in all parts of the body. Activity keeps the muscles in tone and makes the processes of elimination more active. Activity is one of Nature’s laws and is essential in the vital expressions of life in the body. This is shown by the provisions Nature has made for such activity. Especially are the active occupations to be preferred over the sedentary for young people and for those up to the age of forty-five or fifty. After this age the sedentary occupations are not so detrimental.
Fatigue
Fatigue comes as a result of overwork and is a purely personal factor since the amount of work that may be performed before producing fatigue will vary in different individuals. Fatigue is produced by an accumulation of toxines and waste material in the body when katabolism is greater than anabolism. This may be brought on by overtaxing the body to the point where it is impossible for Innate Intelligence to rebuild the tissues as rapidly as they are being torn down. It can readily be seen that if there should be an accumulation of waste material from faulty metabolism due to interference with transmission, fatigue would be produced sooner and with less work than in the individual normally excreting the poisons.
If one part of the body or one set of muscles is overworked fatigue neurosis will be produced. There may be loss of motor function due, not to interference with transmission of motor mental impulses, but to the fact that the organ, usually a muscle, becomes an unfit medium for the expression of the mental impulses. A good illustration of this is writer’s cramp, and cramps among typesetters and telegraphers. In these cases, however, there are usually local subluxations that should be adjusted.
HYGIENE AND SANITATION OF INDUSTRIAL ESTABLISHMENTS
Space Per Individual
In some states the legislatures have established a minimum of 400 cubic feet of space for each individual, but this is not sufficient in some occupations and under some conditions. The amount of space per workman must of necessity be governed by several factors: namely, character of the work performed, character of the building, the hygienic conditions of same, the type of ventilation used, whether natural or mechanical, and the methods of heating and lighting. In some trades and under certain conditions 1000 cubic feet space per workman would not be excessive.
Character of Buildings
When practicable the building should be constructed especially for the kind of work to be carried on within. It should be fireproof and of a material that will lend to the hygienic demands in industry.
We do not want to pass over this subject without calling the student’s attention to the effect which may be produced by the physical, mental and nervous strain under which the work is performed. If the worker is under great tension a great amount of energy will be used up and fatigue will appear early. This will have a marked effect upon the individual and tend to lessen his efficiency. If work is performed under great physical strain, the muscular activity is greater than the muscles are able to express. Then there will be not only fatigue but actual injury done the muscles and other structures. Under such conditions the vital organs will also be overtaxed. This may result in dilatation of the heart, hernia, aneurysms, or in a general weakened condition of the body. The results of mental strain, responsibility and worry are not without their adverse effects.
Lighting, Heating and Ventilating Work Places
Industrial hygiene should be concerned about the temperature, humidity, air pressure, light, ventilation, and heating of the work place. The building should be well lighted. If possible natural light should be provided even though the first cost is considerably greater than that of artificial lighting. There will not only be a better grade of work done in natural light and with less eye strain, but the general health of the workmen will be better. If artificial lighting is used it should be electric light, since it produces less impurities and provides a more even light. The light should be evenly distributed and of a proper distance from workmen so that it will not be reflected directly into their eyes. If the occupation takes the worker out of doors then these features can not be controlled, but in this event attention must be given to the clothing of the workman. Sudden changes in the temperature should be avoided as much as possible. Innate is capable of adapting the body to extremes in temperature, but must be given a sufficient amount of time in which to bring about these changes. Men may work in the frigid temperature or in the torrid temperature and if properly clothed and acclimated will suffer no ill effects.
In many industries the laborers are forced to work in artificially high temperatures. Blast-furnace workers, glass blowers, miners, bakers, and stokers must remain in extremely high temperatures. The body may be adapted to such temperature, but the effect of the continued expenditure of energy necessary to bring about this adaptation will show adverse effects upon the body. There is a tendency to respiratory disorders and a thickening of the blood plasma which disrupts the circulatory system. Heat also has a detrimental effect upon the eyes and there is a tendency to rheumatism.
Air of a high relative humidity is objectionable from a hygienic standpoint because it interferes with perspiration and evaporation. Workers constantly exposed to atmosphere that is too damp will have a tendency to incoördinations involving the bodily secretions and respiratory disorders. The ill effects of such an environment are rather marked and if it is necessary to maintain a high relative humidity because of the processes carried on there must be special provision to guard the health of the workers. This may be accomplished by short hours and frequent periods of rest and relief from the high humidity.
Normal air pressure is fifteen pounds to the square inch, but there are many industries in which the work must be done under a greater or a less pressure. Mountain climbers are subjected to decreased air pressure while caisson workers and divers must work under greatly increased air pressure. Decreased air pressure is especially detrimental to those suffering from cardiac disorders, and may in some cases result in death. The effects of increased air pressure have been elaborated upon in another chapter and the student is referred to that section.
The location of the work is important. Subsurface work is more detrimental to health than surface work unless special precautions have been taken to make the place of work conducive to the expression of life. Subsurface workers such as miners are subjected to great heat, lack of proper light and ventilation, accumulated gases, dampness and poisons. There is also greater danger from accidents and explosions.
Industrial Dusts
In a trade in which much dust is produced there should be proper mechanical ventilation. The vacuum and plenum system should be employed. There is no factor in the industrial life more detrimental to the workman than that forcing him to breathe vitiated air laden with dust and other impurities produced by the processes employed in the trades.
The extremely dusty trades should be separated from the less dusty ones and special provision made to carry away the dust. It is often possible to substitute machinery for handwork in these trades. When the laborers are forced to work in very thick dust they may be protected in a measure by the use of respirators worn over the mouth and nose. These will catch some of the dust and act as filters.
It is often possible to place hoods directly above the machines in these trades and by means of a vacuum fan the dust is carried out through tubes.
The effects of dust upon the worker depend upon many factors. These might, however, be classified as conditioning factors in the individual and the character of the dust inhaled.
Dust from metals and minerals may produce mechanical injury to the membrane of the respiratory tract because of the sharp edges. Inhalation of dust might also bring about catarrhal conditions and coughs. There may be deposits of dust in the bronchi and even in the parenchyma of the lungs from long exposure to and inhalation of dust. This may result in consolidation and other conditions which may be purely adaptative on the part of Innate Intelligence to compensate for the presence of the foreign substances.
In F. Hoffman’s Bulletin of the Bureau of Labor, Vol. LXXIX, he gives the following classification of dusty trades according to the character of the dust produced:
“Group I—Exposure to Metallic Dust: Grinders, polishers, tool and instrument makers, jewelers, gold leaf and brass workers, printers, engravers and pressmen.
“Group II—Exposure to Mineral Dust: Stone, marble and cement workers, glass blowers, glass cutters, diamond cutters, potters, plasterers, paperhangers, moulders, core makers and lithographers.
“Group III—Exposure to Vegetable-fiber Dust: Cotton ginning, textile, linen, hemp, cordage and paper manufacturers, weavers, spinners, hosiery knitters, lace makers, jute and wood workers.
“Group IV—Exposure to Animal and Mixed Dust: Furriers, taxidermists, hatters, silk, wool, and worsted workers, carpet, rug, rag, and shoddy workers, hair mattress workers and upholsterers.”
The mortality rate from pulmonary tuberculosis and other respiratory incoördinations is very high in the dusty trades.
INDUSTRIAL POISONS
In the case of poisonous gases and fumes the necessity becomes even greater for proper prophylactic measures. The methods used in dusty trades may be here employed, but with greater care. All poisonous materials should be eliminated as far as possible and less objectionable material substituted. This may be done in a great many instances without decreasing the value of the article manufactured. An illustration of this is in the substitution of red phosphorus for the use of the more poisonous yellow phosphorus in the manufacture of matches. This eliminates danger from phosphorus poisoning.
Price states: “The chief industrial poisons are lead, arsenic and mercury, although phosphorus, copper, zinc, brass, and chromium poisoning are frequently met with in various industries.”
Lead Poisoning
The symptoms produced by lead poisoning are: lead colic in acute cases, loss of appetite, cramps, pain in the joints. There will be bluish lines found along the edge of the gums; wrist drop and loss of motor function in the hands and feet; arteriosclerosis, indigestion, restlessness during sleep, anemia, lead palsy, loss of strength and weight and constipation. The patient experiences a disagreeable sweetish taste, and there will be a grayish pallor and pinched expression of the face. In severe cases there may be blindness, great fatigue, apoplexy, insanity and death.
The greatest danger from lead comes in the form of dust or fumes and therefore the poison enters the body principally through the respiratory tract, but it may enter through the digestive tract and through the skin.
Prophylactic measures include devices to protect the workmen by means of respirators, but special effort should be made to keep the air in the breathing zone free from the dust and fumes. Since the poison may be taken in through the skin, special provision should be made to protect the hands and arms in fingering the materials. The workmen should exercise the greatest cleanliness and precaution to prevent ingestion of the lead into the digestive tract. Care should be taken that it is not brought into the mouth by the fingers or by pipe, for example. There is a high mortality from pulmonary tuberculosis among lead workers.
Arsenic Poisoning
The mouth, lungs and skin are the portals of entry for arsenic into the body. Arsenic poisoning is characterized by catarrhal inflammation of the eyes and respiratory tract, anemia, neuritis, gastritis, and degenerative changes in the liver and kidneys. Many of the symptoms of arsenic poisoning resemble those of lead poisoning such as gastric disturbances, anorexia, anemia and loss of strength. There may be progressive muscular atrophy, eczematous eruptions and ulcers of the lips, nostrils and in the folds of the skin.
Arsenic is used in the manufacture of wall paper, artificial flowers, textile fabrics; by taxidermists and as a preservative for hides; it is also used in different preparations to kill insects and parasites.
Mercurial Poisoning
Mercury enters the body through the digestive and respiratory tracts and through the skin. The symptoms usually manifest in this kind of industrial poisoning are headache, gastric disturbances, stomatitis, metallic taste in the mouth and fetid breath; there is swelling and ulceration of the gums that cause the teeth to become loose, and there may be an excessive flow of saliva with a swelling of the submaxillary glands. In severe cases there may be tremors, paralysis, melancholy and loss of memory.
Mercury is used in the manufacture of incandescent lamps where they employ mercury pumps, in the manufacture of barometers and thermometers, in the felt and fur industries, in the manufacture of pharmaceutical preparations and chemical works, and in photography.
Methods used to prevent mercurial poisoning are almost identical with those used in lead poisoning. Special devices should be provided to keep the air in the breathing zone free from the fumes. This can best be accomplished by providing a proper system of mechanical ventilation. The workmen should wear rubber gloves to lessen the possibilities of the absorption through the skin. The workmen should also practice cleanliness and exercise care that mercury is not carried into the mouth by the hands which should be thoroughly washed before eating.
Phosphorus Poisoning
The industrial poison of next importance is phosphorus. This poisoning is confined almost entirely to the match industry. There are two kinds of phosphorus, the yellow or white, and the amorphous or red. The yellow is poisonous and is used in making the “strike anywhere” matches. This, however, is being replaced by the non-poisonous, or more harmless red phosphorus. The safety matches contain no phosphorus and are harmless.
Phosphorus poisoning produces gastric disturbances, bronchial catarrh and caries of the teeth with necrosis of the lower maxillary. Other bones of the body may also be affected by necrosis.
Brass, copper, zinc, and bronze workers are also affected by the dust and fumes from these poisons. Brass workers suffer with brass founders’ ague in which there are chills, vomiting, headache and general depression.
Chromium Poisoning
Chromium is also responsible for industrial poisoning. It is used in the manufacture of dyes and in the coloring of wall paper and fabrics. It affects the mucous membrane lining the nose and throat and produces an inflammation of the eyes and ulceration of the skin.