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Human resources section11-textbook_on_public_health_and_community_medicine


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AFMC WHO Textbook Community Medicine

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Human resources section11-textbook_on_public_health_and_community_medicine

  1. 1. 10095752550
  2. 2. Section 11 : Occupational Health223 Introduction & General Concepts L S. Vaz, A K Jindal, Puja Dudeja 1270224 Health Problems in Important Occupations Ashok K. Jindal, Puja Dudeja 1271 Leo S Vaz, Ashok K.225 Organ / System Diseases Peculiar to Occupational Settings 1274 Jindal, Puja Dudeja Ashok K. Jindal, Leo S.226 Industrial Accidents 1279 Vaz, Puja Dudeja227 Industrial Toxicology Ashok K. Jindal, Puja Dudeja 1281228 General Measures of Prevention & Control of Occupational Diseases Ashok K. Jindal, Puja Dudeja 1286229 Ergonomics Leo S Vaz 1288230 Physical Working Environment Leo S Vaz, Ashok K. Jindal 1290231 Social Security and Labour Laws Ashok K. Jindal, Puja Dudeja 1295232 Medical Evaluation of Workers Leo S Vaz 1298 National Programme for Control and Leo S Vaz, Ashok K.233 1300 Treatment of Occupational Diseases Jindal, Puja Dudeja
  3. 3. the physical hazards and their adverse health effects due to 223 Introduction & General Concepts them. Chemical Hazards : Almost all the occupations in industry Leo S. Vaz, Ashok K. Jindal, Puja Dudeja have scope of exposure to some chemical substance or the other. These substances may be solids, liquids or gases, vapours, fumes, dusts, smoke, mist, fog or smogs.Definition Biological Hazards : Viruses, rickettsiae, bacteria, fungi,‘Occupational health should aim at the promotion and protozoa and helminthes may be transmitted in certainmaintenance of the highest degree of physical, mental and well being of workers in all occupations; the preventionamongst workers of departures from health caused by Mechanical Hazards : Mechanical factors of importance intheir working conditions; the protection of workers in their illness and injury in industry are defective design of machinery,employment from risks resulting from factors adverse to health; defective procedures, unguarded machinery, protruding andplacing and maintenance of the worker in an occupational moving parts, falling heavy objects and poor ergonomics.environment adapted to his physiological and psychological Psychosocial Hazards : Factors responsible for psychosocialequipment and to summarize : the adaptation of work to man illness are frustration due to type of work, risks involved inand of each man to his job’. work, monotony, long working hours, lack of recognition, lack - Joint Committee of WHO and ILO, 1950 of job satisfaction, poor remuneration, poor man management, lack of welfare activities and tensions at home and place ofHealth Hazards in Industry work. The indicators for psychosocial group of are chronicHazards in the industry can be due to physical, chemical, absenteeism, mass leave lock outs, strikes and unexplainedbiological, mechanical and psychosocial causes. Table - 1 gives reduction in production. Table - 1 : Physical Hazards in an industry Hazard Occupation Health Effects Foundry, glass, heavy metal industries, Heat stroke, heat hyperpyrexia, heat exhaustion, heat Heat underground mines, vulcanization of rubber, syncope, heat cramps spinning room of textile industry Armed forces, food processing and preservation Cold Chill blains, frost bite, trench foot, erythrocyanosis industry Light Mines, driving Eye strain, eye fatigue, nystagmus, headache Auditory : Auditory fatigue, permanent hearing loss; Noise Machinery in factories producing loud noise Non auditory : Nervousness, fatigue, decreased efficacy, annoyance, raised blood pressure, loss of sleep Vibration induced white fingers due to Raynaud’s Vibration Pneumatic drill users phenomenon, osteoarthritis of wrists, elbows, shoulders. UV radiation Arc welding Glare and dazzle, pain and gritty feeling in the eyes Radiography, radioisotope use, processing Ionizing of plastics, food preservation, industrial Cancer, leukemia, aplastic anemia, pancytopenia radiation radiography, industrial hydrology, chemical industry and medical research • 1270 •
  4. 4. pattern making can release products which may cause asthma Health Problems in Important 224 Occupations in exposed workers. Vapours from various resins can initiate severe allergic reactions. Carbon monoxide gas is produced in substantial amounts by a variety of furnaces. Exposure Ashok K. Jindal & Puja Dudeja to concentrations of 500 to 1000 ppm for approximately 30 minutes may precipitate headache, accelerated breathing, nausea, dizziness and mental confusion. Thus a possibleHealth Hazards in Foundry Work secondary effect of exposure is an increased risk of accidentFounding consists of pouring molten metal into a mould which and injury to the worker. Various metal fumes may be generatedis made to the outside shape of a pattern of the article required during founding processes, especially during melting andand contains, in some case a core which will determine the pouring operations. Lead, magnesium, zinc, copper, aluminum,dimensions of any internal cavity. The basic principles of cadmium, antimony, tin and beryllium fumes are commonlyfoundry work have hardly changed over the years though a lot present in non - ferrous foundries. Iron oxide is the major fumeof modernization has come, making plants more mechanized generated in iron and steel operations. ‘Metal fume fever’ mayand automatic. Molten metal is introduced into the mould. result from exposure to these contaminants. This is an acuteAfter cooling occurs, the mould is subjected to a ‘shakeout’ illness of short duration which commences some hours afterprocedure, which releases the casting and removes the core. inhalation of the metallic fumes. The initial symptoms are flu -The casting is then cleaned and any extraneous metal is like; nausea, headache, dry throat and coughing, and muscularremoved from it. pains, chills and sweating may occur later. Recovery is usual within 24 hours after removal from exposure. The lead hazardProcess in furnace cleaning, dross disposal and the fettling of leadThe various processes involved in foundries include Moulding alloys deserves particular attention. Besides dusts & fumes in& pattern making, Core making, Melting & pouring, Shakeout foundries are known to have carcinogenic properties.(Knockout) and Dressing & cleaning. Occupational Dermatitis : Formaldehyde, isocyanates, variousThe various process outlined in the preceding section give rise resin products associated with pattern making and core makingto heat, molten metal splashes, dusts, noise, gases and vapours processes can irritate the skin and may precipitate allergic skinin the foundry environment. If these hazards are not controlled reactions.or contained, serious health effects in exposed workers can Noise Induced Hearing Loss and Related Effects : The foundryresult. Foundry work also involves various manual operations process generates noise from various sources, including scrapwhich carry a risk of physical injury. The occupational health handling, furnace charging and EAF melting, fuel burners,and safety issues are encountered during foundry activities shakeout and mould / core shooting, and transportation andinclude Physical hazards, Radiation hazards, Respiratory ventilation systems. Some fettling workers have been shownhazards, Electrical hazards, Noise exposure, Burial hazards, to be exposed to levels of noise over 100 db; shakeout andand Fire & explosions. The common and important ones are knockout processes are typically associated with readings ofas follows : 90 - 110 db. Mechanical sand mixing processes and forcedSilicosis : Silica dust presents a prominent hazard of silicosis. draught furnaces may produce noise levels of 90 - 100 db.This dust is generated during mixing, moulding, shakeout and Extraction fans, die - casting machines, core - making and shelldressing operations, and during sand conditioning for re - use. - making equipment may also be sources of excessive noise.The dust arises from quartz in the sand, and the concentration Vibration : Pneumatic grinding and chipping tools used inof free silica in the air varies with the handling process, the dressing the cooled castings may cause vibration inducedefficiency of dust control, the chemical composition of the sand health effects in operators. Hazardous vibration equipmentand the physical state of the sand, that is, whether the sand is may also be utilized in shakeout and core removal operations.screened or un-screened, wet or dry and is either dumped or re-milled, with water and binder added before it is re - used. The Heat and Heat Stress : Radiant heat is the major contributoramount of respirable dust is increased by such re - use. Sand to the heat load imposed on the worker by the dry at the mixing or ‘mulling stage prior to mould making’, Convective heat transfer adds to this radiant heat. Protectiveand at the shakeout stage; this dry sand is potentially more clothing is worn for protection against the heat radiating fromhazardous than wet sand. Screened sand does not produce as the heat sources and against contact with molten metals.much silica dust as unscreened sand and pure quartz sand is Such clothing greatly restricts the potential for body heatmore hazardous than olivine sand. Abrasive blasting processes loss via evaporation. The effects of heat range from decreasedmay involve the use of sand containing high concentrations of concentration to painful cramps, fainting, heat exhaustionfree silica. and heatstroke. Heat stress can also aggravate the effects of exposure to other agents such as noise and carbon monoxide.Irritation, Allergy, Asthma, Metal Fume Fever, Malignancy:In addition to dusts, the air in foundries may contain the Accidents & Injuries : Serious burns may result from splashespotential irritants like formaldehyde, various amines and of molten metal in the melting land pouring areas of foundries.phenol. These contaminants are generated primarily by Frequent, unprotected viewing of white - hot metals in furnacesthe core making and moulding processes, and may irritate and pouring areas may cause eye cataracts. Eye injures fromthe eyes and the respiratory tract. Some hardwoods used in molten metal or fragments of metal may occur in pouring and • 1271 •
  5. 5. dressing areas, during continuous casting processes, non - recovering from a fever, and any dehydrated worker must beferrous molten metals, such as copper and aluminum, may regarded as being in a high - risk category for heat illness.explode violently if they contact water. Injuries related to the Unacclimatised persons must be given time to acclimatize tomanual handling of materials, and injuries due to falls, may work in the heat. Planned job rotation can assist in reducingoccur. Grinding wheels used for dressing small articles may exposure to heat. Cool water should always be available inresult in hand injuries. close proximity to hot working areas and encouragement bePreventive Measures given for the use of these facilities. The exposure of workers to radiant heat can be reduced by the strategic positioning ofMonitoring & Evaluation of Exposure : Monitoring of shields between workstations and heat sources. Clothing shouldthe work environment, personal monitoring and biological be carefully selected so that a balance between protection andmonitoring should be undertaken, In some cases, biological facilitation of heat loss through evaporation is achieved.monitoring may be required to supplement static or personalmonitoring. When developing a monitoring programme in Personal Protective Equipment : Personal protective equipmentfoundries, due consideration should be given to the hazards such as goggles, padded gloves, ear muffs must be used by thein the foundry. In the control of health hazards due to specific workers. If the mechanical ventilation in the foundry is notcontaminant, where it has been demonstrated that the exposure adequate in removing the dust at all points of contamination,of the employee to the contaminant is approaching the relevant the wearing of personal respiratory protective equipment,exposure standard, or where biological monitoring indicates such as a face mask/respirator, is a complementary preventivethat an unacceptable exposure is occurring, immediate action measure together with local exhaust ventilation. If operatorsmust be taken to reduce the health hazard and intensive are required to work inside the enclosure, a continuous - flow,monitoring should continue. Worker exposure to dusts, gases air - line respirator must be worn.and vapours should be kept as low as workable. Exposures Education and Training : All employees working with foundryshould be well below the exposure standards recommended in hazards must be informed of the hazards and the precautionsthe Factories Act 1948. necessary to prevent damage to their health. EmployeesEngineering Control Measures exposed to contamination hazards should be educated in the(a) Elimination/substitution and process modification viz. need for, and proper use of, facilities, clothing and equipment quartz sand can be substituted by olivine sand in ‘sand and thereby maintain a high standard of personal cleanliness. blasting’ as it is less hazardous. Silica - based polishing Health Assessment : Pre - placement examination and periodic pastes should not be used in metal cleaning operations. medical examination of all worker should be done annually for(b) Engineering controls like local exhaust ventilation early identification of health effects and for documentation for should be provided at the mixing or mulling stage as the compensation claims. sand is dry. It is a means of controlling carbon monoxide Noise Management Techniques : emissions at their source. Total enclosure of abrasive and ●● Enclose the process buildings and / or insulate them cleaning operations should be provided. Potentially irritant ●● Cover and enclose scrap storage and handling areas, as vapours or fumes generated in core making or moulding well as shake out and fettling processes processes should be collected by exhaust ventilation at the ●● Enclose fans, insulate ventilation pipes and use dampers point of emission. ●● Implement management controls, including limitation of(c) The reduction of noise at the source or in the transmission scrap handling and transport during night time. Noise path should be achieved wherever workable. abatement measures should achieve the ambient noisePreventing Physical Injures levels(a) Mechanically propelled vehicles or machinery should be inspected regularly. Contact between molten metal and Health Problems of Agricultural Workers water must be avoided. All ladles and other equipment Agriculture is art/practice of cultivating land. WHO defines it used for handling metal should be completely dry before as an industry comprising of all forms of activities connected contacting molten metal. with growing, harvesting and primary processing of all types(b) Good house keeping practices are to be followed. of crops. It also includes activities related to breeding, raising(c) Floors around furnaces should be of slip - resistant, non - caring for animals in the farms and tending gardens and combustible material, kept free of obstructions and cleaned nurseries. Any person engaged either temporarily/ permanent in regularly. activities related to agriculture is called as agricultural labour.(d) Persons would be prohibited from entering furnace areas Agricultural sector occupies a key position in our country. when the temperature exceeds 50°C. It provides employment to about 65 per cent of the working(e) Foundries should be equipped with safety blankets, population of India (5). It is the major source of income for automatic emergency showers or hoses to extinguish about three - fourths of India’s populations who live in villages. burning clothing. Agricultural workers constitute by far the largest segment in(f) Self - contained breathing apparatus must be used in the unorganized sector. Most of them are listed as cultivators emergencies when high carbon monoxide concentrations (large, medium and small) of whom approximately 50% belong are suspected. to the category of small and marginal farmers. A significantMinimizing the Risk of Heat Illness : People who have any number of them are engaged in livestock, forestry, fishing,history of heat intolerance or a circulatory disorder, anyone orchards and allied activities. Agricultural workers constitute • 1272 •
  6. 6. the most neglected class in Indian rural structure. Their income Others : Agriculture being labour intensive activity musculo -is low and irregular. They do not possess any skill or training skeletal disorders are the leading cause of the occupational illand have no alternative employment opportunities. Socially, health (8). This risk of musculo - skeletal disorders is highera large number of agricultural workers belong to scheduled in agricultural workers because of the longer working hours,castes and scheduled tribes. Therefore, they are a suppressed practice of lifting heavy weights and inconvenient work posture.class. They are not organized and they cannot fight for their There is poor application of ergonomics principle to agriculturalrights (6). Occupational hazards of agriculture sector are given tools. There are no legislations related to health, safety andin Table - 1 (7). welfare of agricultural workers. There is no social security forThe various types of respiratory diseases in agriculture are agricultural workers other than crop insurance. There is no acthighlighted in Table - 2. to provide welfare to the workers. Living condition of these people, low educational status, lack of medical facilities in Table - 2 : Respiratory diseases in agriculture rural areas aggravate there problems. Being in close proximity to animals agricultural labour also faces hazards of zoonosis. Agent Disease Women in Agriculture Saw dust Carcinoma nasal septum Women in India are the major work force in agriculture and Sugar cane dust Bagassosis perform almost all the agricultural activities. Since agriculture Cotton, flax, sisal or hemp Byssinosis by its nature is an unorganized sector and in case of women, their contribution is generally unrecognized. In fact some economist Husk with thermophilic Farmer’s lung have use the term ‘Labour for Love’ while describing the status actinomycis of Indian women who is married with farmer’. A significant (Micropolyspora faeni) proportion of women work force in rural areas is dependent Tobacco dust Tobaccosis for their livelihood (8). The lives of these women are plagued Dusts of grains, rice, coconut Asthama, COPD by high levels of occupational, poverty - induced diseases and fibres, tea reproductive health problems. Abortions, premature delivery, and still birth are outcomes of their deprived socio - economic, Cocoa bean handling Respiratory allergy Table - 1 : Occupational Health Hazards of Agriculture Exposure Health Effect Remarks Dehydration, heat cramps, heat exhaustion, heat Most agriculture occupations are performed Weather, Climate stroke, skin cancer outdoors Snakes, insects Fatal or injurious bites and stings Close proximity in high incidence Injuries ranging from cuts to fatalities, hearing Most farm operations require variety of skills for Sharp tools, farm impairment from loud machinery which workers have little formal training and there equipment are few hazard controls on tool equipment Numerous types of (largely unreported) Agricultural work involves awkward and Physical labour musculoskeletal disorders, particularly soft - tissue uncomfortable conditions and sustained carrying of carrying loads disorders, e.g. back pain excessive loads Acute poisonings, chronic effects such as More hazardous products are used in developing Pesticides neurotoxicity, reproductive effects and cancer countries with minimal Personal Protective Equipment (PPE) Irritation of the eyes and respiratory tract, allergic Agricultural workers are exposed to a wide range Dusts, fumes, reactions, respiratory diseases such as Byssinosis, of dusts and gases from decomposition of organic gases, particulates bagassosis, asthma, chronic obstructive pulmonary materials in environments with few exposure disease and hypersensitivity pneumonitis controls and limited use of PPE use in hot climates. Skin diseases such as fungal infections, allergic Workers are in direct contact with environmental reactions and dermatoses pathogens, fungi, infected animals and allergenic plants Parasitic diseases such as schistosomiasis, malaria, Workers are in direct contact with environmental Biological agents sleeping sickness, leishmaniasis, ascariasis and pathogens, fungi, infected animals and allergenic and vectors hookworm plants of disease Animal - related diseases or zoonoses such as Workers have ongoing, close contact with animals anthrax, bovine tuberculosis and rabies (at least through raising, sheltering, and slaughtering 40 of the 250 zoonoses are occupational diseases exposed to a mix of biological agents, pesticides, in agriculture) and diesel fumes, all linked with cancer • 1273 •
  7. 7. cultural, and political conditions and gender inequities (9). The from money lenders to buy costly fertilizers and pesticides. Thesocio - cultural norms and practices that endanger the women’s general public health system of the country is also in a poorhealth are reflected in their low age at marriage and low age at state and has very little to offer as preventive, promotive andfirst childbirth. Women working in fields shoulder the double curative care to this class. This is evident from the large numberburden of work - within home and outside home - and stretch of suicides that have taken place among farmers. There is athemselves beyond their physical capabilities to procure definite need to take case for social security for this sector. Inadequate economic security for their families. They bear the this connection government has come out with National Policybrunt of the deprivation due to the gender inequities. The low for Farmers 2007(10). The objective of the policy is to improvenourishment and the resultant general under - nourishment the economic viability of farming through substantiallylead to illnesses, which prevent them from translating their improving net income of farmers. The policy emphasis onlabour endowments into economic resources. In short, the increased productivity, profitability, institutional support, andpoverty of the women agricultural workers encompasses a wide improvement of land, water and support services apart fromrage of unmet needs and gender - specific inequities including provisions of appropriate price policy, risk mitigation measureslack of adequate access to education, employment, resources as and so on. Government of India has recently taken severalwell a range of violence, relative powerlessness, and feelings of initiatives such as the National Horticulture Mission, thehurt, low self - esteem and denial of identity. National Bamboo Mission, reforms in agricultural marketing,Legislations the revitalization of cooperative credit structure and setting up of the National Fisheries Development Board and theThough agriculture is the major occupation in India and gives National Rainfed Area Authority. More recently, the Nationalnot only employment but is also responsible for providing food Food Security Mission and the Rashtriya Krishi Vikas Yojanasecurity to the nation but unfortunately only lip service has (Additional Central Assistance Scheme) have been approved tobeen paid in providing social security for the welfare of the substantially enhance investment in agriculture and increaseworkers engaged in this class. As a result they can go into production and productivity.penury due to floods, droughts, extensive loans under taken for all dust damage to the alveolar part of lung including the Organ / System Diseases Peculiar 225 to Occupational Settings airways which do not have mucociliary lining (18). Therefore the term does not include bronchitis, asthma or cancers. In other words the inorganic dusts like silica, asbestos and coal Leo S Vaz, Ashok K. Jindal & Puja Dudeja cause pneumoconiosis where as organic dust like cotton and cane sugar cause bronchitic changes and do not qualify to be called pneumoconiosis.Occupational Lung Disease Body Defence Mechanism : Dust is an aerosol consisting ofAn occupational lung disease is a lung condition that develops finely divided particulate matter, size 1μ- 150μ, organic oras a result of a person inhaling harmful substances at his or her inorganic, generally inanimate and produced by attrition ofplace of work. Occupational lung diseases are the most common solid matter by processes such as cutting, sawing, crushing,work - related illness but fortunately many are preventable or grinding, blasting etc. Dust particles 10μ or more in size arecontrollable with proper treatment. Occupational lung diseases released in size settle down on the floor due to effect of gravity.are classified into two major groups : pneumoconiosis, caused The dust particles of such larger size which are inhaled areby dust that gets into the lungs, and hypersensitivity diseases, mostly arrested by the upper airway filter of hairs in the nostrilssuch as asthma, that are caused by the lungs’ overreaction and by the folds of mucosa over the turbinates and carried downto airborne pollutants. Table - 1 depicts important features of in the mucus and swallowed over airway filter, carried in thevarious lung diseases. mucus back to the larynx and swallowed. Irritant particles arePneumoconiosis thrown out by reflex acts of coughing and sneezing. Of smaller particles those are inhaled in size of 3 - 10μ are tackled by theBy ILO definition it is the accumulation of dust in the lung mucociliary lining of lower airway, filter, carried in the mucusand tissue reaction to its presence. The concept of using the back to the larynx and are swallowed. Particles 0.5μ - 3μ in sizeterm pneumoconiosis has undergone a change. Earlier this reaches the alveoli and get deposited causing damage to theterm was used to describe all lung related problems caused lungs, producing various types of pneumoconiosis. Particlesby any kind of dust (17). However the term should be used less than 0.5μ in size have a slim chance of settling down in • 1274 •
  8. 8. Table - 1 : Comparison of Different Types of Lung Diseases Farmers’ Silicosis Anthracosis Asbestosis Byssinosis Bagassosis Siderosis lung Type Major Major Major Major Major Major Major Occupational Silica dust Coal miners Asbestos Exposure to Fibrous Agricultural Foundry exposure mines, and handlers industry; cotton dust residue workers workers, tunnels : : carbon brake and released of sugar grinders and quarries, electrode fire resistant during cane in welders foundries; manufacturing product cording, cardboard potteries manufacturing spinning and and paper and soap weaving industry Initiating Chemical Unknown Mechanical Allergy Infection Infection Absent stimulus Pathogenesis Fibrosis Two distinct Asbestos fibres Cotton dust Fungal Fungal No tissue initiated by stages - simple initiate fibrosis inhalation infection infection reaction or silicic acid CWP and of pulmonary produces leading leading to functional leading to PMF. Average tissue, allergic to acute bronchitis impairment nodular time taken emphysema reaction bronchitis and broncho though fibrosis, is 12 years and its leading to and - pneumonia lungs are emphysema associated broncho broncho - loaded with and right complication - spasm, pneumonia iron dust. heart emphysema failure. and its Pulmonary complications TB in 50% casesthe lungs and are mostly breathed out in the expiratory air. be taken to see if the individual has pulmonary tuberculosisSilicosis : Silicosis is a disease caused by breathing air or any other lung disease. Basic lung function tests shouldcontaining silica in its free state, as quartz (SiO2). The be carried out, including measurement of the Vital Capacitypathological result is a generalized fibrotic change and & Forced Expiratory Volume in one second. Dust control isdevelopment of miliary nodules of variable sizes in both lungs. the most important engineering procedure to reduce risk. If aThe clinical manifestations are shortness of breath, decreased significant number of workers develop silicosis within 20 - 25chest expansion, a lessened capacity for work and chronic years of first employment, the dust control measures should bebronchitis with the absence of fever and characteristic X - ray suitably revised.findings. There is an increased susceptibility to tuberculosis. Asbestosis : Asbestos is a fibrous material. These are silicates;The diagnosis of the disease mainly depends upon occupational silica combined with bases like magnesium, iron, calcium,history symptom complex and the radiological findings. The sodium and aluminum. These are of two types - serpentinepathological process starts only when the dust particles, which and amphibole. However, 90% of production is of serpentinecontain silica in a free state such as quartz (SiO2), reach the variety. Asbestos used in the manufacture of asbestos cement,alveoli. Most of the dust inhaled is expelled by the ciliated fireproof textiles, roof tiling, brake lining, gaskets, and suchepithelium and some part is eliminated by phagocytosis, which other items. Asbestos fibres are inhaled and fine dust getsbrings up the particles and discharges them to the ciliated deposited in the alveoli. These are insoluble and cause chronicepithelium and the cough mechanism expels them. However, irritation resulting in pulmonary fibrosis of lungs. It can alsowhen the fine particles are present in the atmosphere in a large cause carcinoma of bronchus and mesothelioma of pleura andquantity, some find way to the finer air passages. They first peritoneum (more due to amphibole variety). These possibilitiescause the inflammation of the ciliated epithelial cells with are more when exposure is coupled with smoking. The diseasetheir subsequent destruction, reducing the first line of defense. appears after an exposure of 5 to 10 years. The fibrosis isEpithelial cells crowded with silica dust get aggregated into peribronchial, diffuse and more near the bases in contrast todefinite clumps around which fibrosis occurs. This damage fibrosis due to silicosis. Clinically, patient gets cough, pain inproduced in the lung is permanent. It is liable to activate the chest and dyspnoea disproportionate to the clinical signs inpreexisting tubercular focus and develop tuberculosis. The lungs. In advanced cases, there may be clubbing of fingers,disease finally produces emphysema and corpulmonale. cardiac failure and cyanosis. Sputum show asbestos fibresVery little can be done once the disease has set in and therefore, coated with fibrin called “asbestos bodies”. X - ray chest showsprevention is most important, pre - placement & periodic health a ground glass appearance in lower parts of lungs. Diseaseexaminations of the worker are important. Chest X Ray is to is progressive even after removal from exposure. Preventive • 1275 •
  9. 9. measures include : It is associated with breathlessness, clubbing, bronchitis,(a) Adopt all measures for dust control. The legal exposure emphysema and right heart failure. This condition may be due limit in India is 23 fibres/ml of air. Fig.-1 shows various to quartz, coal mine dust plus rheumatoid arthritis (as seen methods of dust control. by Dr. A Caplan in 1953 in New South Wales Coal mines).(b) Substitute it with safer materials like glass fibres, calcium Progressive massive fibrosis is characterized by formation of silicate, plastic foam etc. where feasible. a mass 3 - 10 cm or more in length in the lung tissue and(c) Use safer varieties of asbestos (chysotile and amosite). lying parallel to the pleura : this may cavitate after many years(d) Periodic medical examination of workers and elimination releasing large quantities of black necrotic tissue and dust of susceptible from workforce. which is coughed out as an expectorant resembling black ink(e) Use of personal protective measures. (melanoptysis). Control measures centre on dust control and(f) Good housekeeping & the use of vacuum cleaners. early detection of the disease.(g) Use of respirators & protective clothing is to be In X - rays, 3 stages are seen in simple CWP First stage - . encouraged. Generalized mottling of the lung through which exaggerated(h) Health education of the workers. lung markings are seen. Second stage - Mottling becomes very(j) Continuing research to find out safer substitutes (19-24). dense and exaggerated lung marking cannot be seen throughAnthracosis or Coal Worker’s Pneumoconiosis : (Synonyms: them. Third stage - Very dense reticulated opacities seen allAnthracosis, Coalminer’s consumption, phthisis melanotica, over the lung. The reticular markings indicate coal dust fociblack spit). The diseases due to inhalation of dust in coal around the tips of the bronchioles. A person suffering frommines are simple coal - worker’s pneumoconiosis (CWP) and silicosis is both breathless and ill but a person with CWP iscomplicated coal - worker’s pneumoconiosis. Simple CWP is breathless but does not look ill. It has been seen that theredue to chronic exposure to coal dust with a low level of other is a negligible risk of developing CWP over a working lifetimemineral dust contamination. In this condition, the progression with a dust level below 2mg/cu.m. The basic lesion of CWPof small rounded opacities may be associated with only a is the local macule. Air spaces adjacent to the macule getslight loss of ventilation, which is insufficient to produce any enlarged, consistent with focal emphysema. A small percentagedisability. It can be very difficult to differentiate these effects of miners develop complicated CWP or PMF diagnosedfrom those of aging and cigarette smoking. Complicated CWP is radiologically by the appearance of a density 1 cm or in which CWP is complicated by the additional pathology of Recent studies suggest that superoxide anion generation bylarge masses of solid tissue within the lung parenchyma. The alveolar macrophages may play a role in the lung injury ofcondition usually occurs after 20 - 30 years in the occupation. CWP The introduction of improved ventilation, water spraying . Fig. - 1 : Methods of Dust Control Methods of Dust Control Medical Control Environmental Control Personal Control  Proper selection of persons Dust control at the  Personal hygiene for dusty trades source Control  Respiratory protection  Periodic medical (Dust respirator, Air examination Prevention of escape of mask supplied with air)  Epidemiological analysis dust into atmosphere Change in Process Control by substitution  Segregation  Segregation  Rotary diamond drills  Silica carbide/aluminum  Proper enclosure  Proper enclosure in place of pneumatic grinding wheels instead  Ventilation general &  Ventilation general & drills (in mines place of sand stone wheel exhaust exhaust  Use of permanent  Ground flint replaced by  Reduce magnitude of  Reduce magnitude of air mould in Foundry non-silica substitute in air displacement by displacement by review  Use of plastic sand pottery making review of design of of design of process mixture to form moulds  Silica free parting process equipment equipment in foundry compounds in iron  Plant layout  Plant layout  Use of dust free flint in and steel industry  Segregating of dust and  Segregating of dust and glaze of potteries in  Abrasive blasting non-dusty operations. non-dusty operations. place of quartz mixture replaced by wheel shot  No crowding  No crowding  Wet grinding of blasting  Mechanization  Mechanization washing quartz Good house keeping  Good house keeping • 1276 •
  10. 10. and mechanized equipment has greatly reduced dust levels in asbestos), a biological agent (such as hepatitis B virus), or anthe mines. Medical surveillance is the second most important industrial process in which the specific carcinogen may eludemeasure to prevent disabling CWP . precise definition (such as coke production) (13). CommonOther Lung Diseases occupational carcinogens include Benzidine, 2 - naphylamine, Arsenic, Beryllium, Cadmium, Chromium, Nickel, Asbestos,Byssinosis : Bronchopulmonary diseases caused by exposure Silica, Talc containing asbestiform fibres, Wood dust, Benzene,to airborne dust of cotton, flax & soft hemp leads to Byssinosis. Trichloroethylene (TCE), Polychlorinated Biphenyls (PCBs) andIt is a chronic respiratory disease characterized by tightness of Ethylene oxide.the chest & breathlessness at work after the weekend or otherabsence. It is also called ‘Monday Fever’. This is probably due Preventionto a histamine releasing substance. In addition to histamine Occupational cancers have two characteristic features namelyrelease, exposure to cotton dust causes irritation in the upper they are preventable (14) and most occupational carcinogensrespiratory tracts & bronchi, which after prolonged exposures have first been recognized by clinicians (15).slowly progresses to chronic obstructive pulmonary disease. Primary PreventionIn early stages there may be decline in FEV1, which may be ●● Recognising presence of hazards and riskssymptomless in some workers. Within, one or two days, most ●● Educating management and workforcesymptoms tend to disappear except for irritation in the upper ●● Eliminating exposure by substitution and automationrespiratory tract. As the disease progresses, the chest tightness ●● Reducing exposure by engineering controls (such as localis accompanied by breathlessness, the symptoms becoming exhaust ventilation and enclosure), changes in handling,worse & persisting for a longer time. In its late stages the and altering physical form in processingdiseases resembles chronic bronchitis & emphysema, except for ●● Monitoring exposure and maintaining plantthe history of chest tightness & decline in ventilatory capacity, ●● Protecting workers by means of personal protectivecharacteristically worse at the beginning of the work week. equipmentChest X - rays do not show any specific changes. Prevention ●● Limiting accessincludes Pre - placement examination, which should include ●● Providing adequate facilities for showering, washing, andChest X ray, VC and FEV1. Periodic medical examination is changingrecommended every year. In groups of workers, a drop of more ●● Legislative provisionsthan 10% in FEV1 during the work shift on the day after the Secondary Prevention : A secondary approach to preventionweekend holiday may provide advance warning that workers consists of detection at an early stage to prevent the furtherare liable to develop Byssinosis. progression of diseases and increased survival by institutionOccupational Asthma : Occupational asthma is a form of of treatment. Screening tests and medical surveillance - forlung disease in which the breathing passages shrink, swell, example, exfoliative urinary cytology and skin inspections.or become inflamed or congested as a result of exposure toirritants in the workplace. Occupational asthma is a lung Occupational Dermatosesdisorder characterized by attacks of breathing difficulty, An occupational dermatitis is one where the inflammatorywheezing, prolonged exhalation, and cough, which is caused reaction is caused entirely by occupational contact factors orby various agents found in the work place. where such agents are partly responsible by contributing to theHypersensitivity Pneumonitis : Hypersensitivity pneumonitis reaction on compromised skin. The commonest site is handsis an inflammation of the lung (usually of the very small followed by forearms. In case of airborne contact dermatitisairways) caused by the body’s immune reaction to small air - face may be the prime site on inflammation. Contact dermatitisborne particles. These particles can be bacteria, mould, fungi, accounts for at least 60% of occupational skin disease, which, inor even inorganic. Hypersensitivity pneumonitis is usually turn, account for 40 - 70 % of occupationally acquired occupational disease in which exposure to organic dusts, Causesfungus, or moulds leads to acute and over time, chronic lung 1. Physical agents : Heat, Low Humidity, High Humidity,disease. Cold, Pressure, Vibrations, Friction (Coal Mines, ConstructionBerylliosis : Berylliosis (or beryllium disease) is caused by the Workers) and Occlusion, Presence of Sharp Particles (Fibreinhalation of beryllium particles, dust or fumes. Its symptoms Glass), Damage from Minor Lacerations of the Skin, Solarinclude coughing, shortness of breath, fatigue, weight loss or Radiation, Ultraviolet Radiation, Ionizing Radiation.loss of appetite, fever and sweating. Medical tests may reveal 2. Biological Agents : Bacteria, Viruses, Fungi (Confectionersabnormal lung sounds, lung scars, decreased pulmonary - Monilia, Sewage Workers, Doctors), Parasites (Miners andfunction, granulomas (a nodular form of chronic inflammation) Workers in tea gardens - Ankylostomiasis).and an allergy to beryllium. 3. Chemical Agents : These account for 70% of all occupationalOccupational Cancers dermatoses and include :Occupational cancer is any malignancy wholly or partly caused ●● Acids : HCl, HNO3, H2SO4by exposures at the workplace or in occupation. Such exposure ●● Alkalis : Hydroxides, Carbonates of Sodium, Potassiummay be to a particular chemical (such as ß - naphthylamine), and Ammoniuma physical agent (such as ionising radiation or a fibre like ●● Chlorides : Sulphuryl Chloride, Arsenic Chloride, Stannous Chloride • 1277 •
  11. 11. Some examples of substances causing occupational 2. Employer and employee should be aware of the potentialdermatitis are : risks of exposure●● Rubber accelerating chemicals, such as Thiurams and 3. Education of need for good occupational hygiene Carbamates 4. Adequate provision of suitable and effective means of●● Biocides - such as Formaldehyde reducing exposure●● Hairdressing chemicals - such as Thioglycolates, 5. Awareness of limitations of personal protection devices Phenylediamine 6. Engineering or environmental control. Few examples are●● Epoxy resin monomers given below :●● Chromates ●● Substitution of mineral oil by vegetable oils●● Plant allergens - such as Sesquiterpene Lactones found in ●● Segregation and mechanical handling of radioactive Chrysanthemum substancesDiagnostic Criteria ●● Local exhaust ventilation - chromium plating ●● Good general ventilation1. Disease appears during a period of occupational exposure ●● Good housekeeping - mercury and its compounds or within a reasonable period of time after the exposure ●● Safe design of the plants ceases ●● Provision of adequate bathing and washing facilities2. Occurs first on the exposed part ●● Provision of protective clothing3. Disease has not been present previously ●● Periodic environmental survey to ascertain TLV4. Disease improves after the termination of exposure ●● Wet methods5. Disease recurs after exposure 7. Medical methods6. Morphology of the disease is similar to the well known cases resulting from similar exposure and other fellows (i) Pre - placement medical examination : careful and with similar exposure similarly affected. detailed history to exclude allergic tendencies such as eczema/Types asthma. Such people may not be employed in occupations with sensitizers.Occupational dermatitis is commonly of two types Irritantcontact or Allergic contact Dermatitis. Others are contact (ii) Standardized Patch Testurticaria, rubber latex protein sensitivity and photo contact a) Test substances appropriately diluted. Standardized kitsdermatitis. available. b) Apply the patch to the upper or mid back.Management c) Leave the patch in place and keep dry for 2 days before1. Detailed occupational history removing.2. Evaluation of contact factors d) Read tests :3. Patch test followed by recommendation on reducing or ●● The same day that patches are removed stopping exposure to the offending agent and similar ●● One additional reading 3, 4, or 7 days after test initially ones. applied4. Chemical analysis of environmental materials to determine e) Grade test reactions according to intensity : 0 = no reaction whether they contain a substance to which the patient is to 3+ = small blisters patch test positive. Relate relevance of positive reactions to clinical dermatitisPrevention cautiously. Careful history and review of skin exposures must1. Primary prevention is aimed at providing appropriate establish significance. information and protection. (iii) Treatment : Treatment with barrier / moisturizing creams, topical steroids, oral steroids and antibiotics if required. • 1278 •
  12. 12. (h) East and comfort with which it can be used and freedom 226 Industrial Accidents of movement with equipment which should not hamper performance of the worker (i) Maintenance of these equipment Ashok K. Jindal, Leo S. Vaz, Puja Dudeja (j) Periodical check up (k) Good earthingThe most important industrial hazard due to machinery isthe accidental injury. A detailed account of the prevention Safety Auditof industrial accidents is outside the scope of this book. ObjectivesBox - 1 depicts epidemiology of industrial accidents, while (i) Critically evaluate the safety programmeFig. - 1 shows methods of accident prevention. (ii) Evaluate the systems to identify and control hazardsThe first step in any accident prevention programme is (iii) Check that the above system meets the statutory standardselimination of various hazards whilst designing the process. and codes of practiceIf this is not possible, the next best step would be to control Benefitsthe physical, mechanical and chemical hazards in work (i) Strengthening of the Organization safety standard andenvironment by suitable engineering design. But when this programme.also is not possible or is not able to give full protection to (ii) Improve the skill and performance of employee andworkers the third line of defence has to be resorted i.e., the managers.personal protective equipments. These protective equipments (iii) Helps to create group and self awareness and providescannot eliminate hazard or stop an accident taking place. These motivation.equipments merely set up a barrier against the hazards thereby (iv) Identifies specific deficiencies in the safety programme.preventing or minimizing an injury. (v) Provides timely information before any injury producingIn selection of these equipments, the following points are to be incident occurs.borne in mind : Mechanism(a) Type of hazard to be faced Safety audit shall be carried out at three levels(b) Selection of right type of personal protective equipment(c) Availability of correct equipment in good condition at the (i) Level - 1 : Internal Audit inspection by Safety Officers from work spot within the factory once in every three months.(d) Training of workers to use the equipment (ii) Level - II : Audit inspection by a group comprising of 3(e) Convincing the workers that the equipment is used will officers of the factories in the concerned group, once in a period protect them from hazard of six months.(f) Making it a habit with the worker to use the equipment, (iii) Level - III : Annual Audit inspection by the Regional(g) Degree of protection needed Controller of Safety / O.F. Board. Box - 1 : Epidemiology of Industrial Accidents Host factors Agent factors Environment factors ●● Age ●● Improper planning and Physical ●● Sex construction of factories ●● Overcrowding ●● Experience and education ●● Machines ●● Defective lighting ●● Concomitant disease ●● Faulty design ●● Temperature ●● Psychological factors ●● Lack of maintenance ●● Ventilation ●● Personality Traits/ ●● Entanglement of loose ●● Humidity Emotional stability clothes and hair ●● Radiations from surroundings ●● Wearing unsuitable shoes ●● Transmission of Machinery ●● Pressure ●● Carrying improper loads ●● Speed of Work Processes ●● Noise ●● Faulty stepping ●● Faulty planning ●● Vibrations ●● Not using personal ●● Boiler explosion ●● Ionizing Radiation Protective measures ●● Dust explosion ●● Slippery Floors ●● Physical defects ●● Corrosive materials ●● Uncovered drains ●● Molten metal and Hot liquids Social ●● Flying solid particles ●● At work place ●● Metal grinding ●● Domestic ●● Stone dressing ●● Relationship between ●● Riveting workers and management ●● Chipping metal ●● Lack of Safety Policy ●● Electricity ●● Gassing • 1279 •
  13. 13. Fig. - 1 : Prevention of Industrial Accidents Prevention of Industrial Accidents Role of Personal Good Working Planning Processing management protection Environment Foreman and Industrial MO Role of ILO Legislation safety and safety Machines  Design and  Clear Policy  Precautions against  Clothing  Lighting Construction of  Safety Committee toxic Fumes, gases  Dust  Thermal Comforts factory  Job Analysis of each and Dust vapours  Masks  Noise control  Collaboration Worker  Substitution  Respirator  Vibration Control  Industrial MO  Supervision  Segregation  Proper Weight lifting  Radiation Control  Safety Officer  Training of New  Exhaust Ventilation  Precautions against  Chemist Worker/trainee  Periodic MAC Fire & Electrocution  Industrial Hygienist  Industrial Fatigue  Checks of Equipment  Good house keeping  Supervisor  Avoid Long hours  Engineer  Posture  Personnel Officer  Preventing Boredom  Collection & Utilization  Welfare Officer  Recreation of Information of Special  Guards  Union Leader  Welfare Services Dangers in Industry  Painting of Dangerous• 1280 •  Social Worker  Methodological Parts Investigation of Physical  Maintenance and Psychological  Proper Training  Medical Examination Causes  Supervision  Psychological Test  Standardization of  Education of Workers  Physical Check of Statistics on Shop floor Environments  Prescribing safety By-  Accident  Statistics of Accidents laws Investigation  Engineer Designing /  Research  Research setting Machinery  Publicity material - Engineering  Investigation of  Encourage safety - Medical Accidents measures  Human Behavior  Health Education Training  Personal Protective equipment
  14. 14. Scope where accidents are due to unsafe conditions. In case of allThe Audit is necessarily very wide ranging in scope and serious accidents, a Board of Enquiry to investigate in to thecovers all aspects of a company’s operations. Some of the accident shall start investigation immediately on receipt ofbroad areas to be covered for Safety Audit are to study, in intimation by visiting the accident spot so that the evidencedetail, the Safety Policy, Process Safety, Fire Safety, Hazards is not tampered. Photographs may be taken if necessary. Thein the processes and their control, Pollution control, Machine investigations should be towards fact finding and not faultguarding, Housekeeping, Material Handling system, Training finding. The concerned sections shall not disturb the site untilof workers/supervisory staff and Management personnel, it is cleared by the board of Enquiry of Safety Officer.Accident reporting, investigation & analysis, Emergency Accident Returns & Analysis : The accident statisticspreparedness and availability of Health, First Aid, Periodical indicating details of accidents, man days lost, man hoursMedical examination. worked are compiled quarterly. A monthly report on theAccident Investigation : All accidents should be investigated accidents taking place during the preceding month is alsoby the concerned Heads of Sections and an unambiguous compiled. Any accident taking place in the factory shall bereport sent in Form No. 14. Safety section shall investigate analyzed by Safety Section.selected accidents involving plants/machineries/chemicals and produces ill effects much more rapidly and probably in a 227 Industrial Toxicology more severe from than when ingested. Young persons are more prone to lead poisoning than adult. Lead concentration in the working atmosphere should be kept below 2.0 mg per 10 cu m Ashok K. Jindal & Puja Dudeja of air ( 25 - 31). Symptoms : The commonest manifestations of lead poisoningIndustry uses and manufactures wide variety of substances, are blood changes and lead palsy. Lead makes the RBC fragilewhich are either known or suspected to cause toxic effects and causes haemolysis, which results in anaemia within the persons working with them. Industrial toxicology compensatory stimulation of the bone marrow. So immatureis concerned with the study of various substances used in RBC or reticulocytes appear in the blood. The RBC count isindustry either as media for processing some other materials generally below 3 million with haemoglobin under 70 percentor as raw materials or the finished product. The Permissible (Sahli). In ‘Lead palsy’ there is a typical degenerative neuritisExposure Limit (PEL) to a substance is defined as exposure to and subsequent fibrosis. In acute lead encephalopathy, therea maximum time weighed average (TWA) of concentration of a is involvement of the meninges with oedema and increasedtoxicant for an 8 - hour work. The Threshold Limit Value (TLV) intracranial pressure. There may be some capillary damage asis that limit in an environment of a toxic agent or the substance well. The lead line showing blue discoloration of the marginsor the deleterious material which when inhaled by a worker of the gums is a classical sign. A diagnosis of lead poisoningfor a duration of 8 hours per day for indefinite periods will not should be based on clinical finding, biochemical evidence ofcause any harmful effects. excessive lead absorption and by evidence of unusual exposureDetails of industrial toxicology in respect of common and (See Table - 1 and 2).important toxic substances are being described in this chapter. Prevention : It depends on good housekeeping, personalThe general measures of prevention and control are dealt with protection and education of workers and medical supervisionsubsequently. for the detection of hazards the occurrence of poisoningLead followed by its rectification.Lead is ubiquitous in industry and poisoning due to absorption (i) Exhaust ventilation measures so arranged that whatsoeverof lead and its compounds is still common. Lead is the most position the worker assumes the lead dust and fumes arecommonly used metal in industries because of anticorrosive drawn away from his Hazardous process are lead smelting, burning and (ii) Strict periodical inspection of the exhaust system : Allmaking paint, painting, welding riveting, battery manufacture, ducts and their angles should be cleaned periodically.and lead baths connected with heat treatment of metals, (iii) Avoidance of crowding in the workrooms where metallicspecially when carried out in confined spaces. Inhalation of lead is heated.lead dust and fumes is the chief route of poisoning, the next (iv) The floor should be impervious to water, and smooth socommon route is ingestion, cutaneous absorption is rare. It that no lead dust can rapidly absorbed into general circulation when inhaled (v) The floor should be constantly kept wet & swept before • 1281 •
  15. 15. Table - 1 : Manifestations of Lead Poisoning System Evidence of absorption Evidence of incipient poisoning Evidence of definite poisoning General Restive, moody, easily Pallor, Leadline, Jaundice Anemia, Leadline, Jaundice, appearance excited, emotional, lead line Emaciation, “Premature ageing” Persistent Metallic Metallic taste, definite anorexia, Metallic taste, increasing anorexia, nausea Digestive taste, slight anorexia slight colic, constipation and vomiting, marked colic, rigid abdomen System slight constipation marked constipation, blood in stool Slight headache, insomnia, slight Severe headache, increased insomnia, dizziness, palpitation, increased increased dizziness ataxia, confusion, Nervous Irritability, irritability, increased reflex marked reflex changes, tremor, fibrillary System uncooperativeness twitching, neuritis, visual disturbances, encephalopathy hallucinations, convulsions, coma paralysis. Muscle soreness, easily fatigued General weakness, arthralgia, Miscellaneous - hypertension Urine Abnormal lead content Abnormal lead content, Abnormal lead content, Albumin, examination Albumin, Casts Casts, Porphyrinuria, Haematuria Polycythemia, Normal red cell count and Decrease in haemoglobin, decrease in polychromatophilia, haemoglobin, reticulocytosis 50 RBC, increase in cells showing basophilia, Blood increase platelets, - 100 stippled cells per 100,000 anisocytosis and poikilocytosis, decreased changes reticulocytosis, RBC, abnormal blood lead platelets, increase in blood lead abnormal blood lead Table - 2 : List of Bio-Chemical Tests Excessive absorption Acceptable absorption Test Normal Population occupation with in occupation signs & symptoms Blood lead 10μg/dl 75 μg/dl >80μg/dl Urinary lead 10-65μg/g Cr Upto-150 μg/g Cr >150 μg/g Cr Zinc protoporphyrin 16-35 μg/dl Upto 100μg/dl >100 μg/dl Urinary delta aminolaevulinic acid 5 mg/g Cr 6-20 mg/g Cr >20mg/g cr and after the day’s work with a vacuum cleaner. by active treatment.(vi) Workers should wear special work clothes which should Treatment : When lead poisoning is diagnosed, the further be removed before leaving the factory and deposited in exposure should be discontinued, the use of penicillamine and specially provided lockers in order to ensure the prevention Ca - EDTA, chelating agents, help in bringing down the blood of contamination of private clothes. lead levels by promoting lead excretion in urine. A saline purge(vii) Suitable respirators against lead dust and fumes should be will help to remove unabsorbed lead from the gut and also will use and inspected regularly. relieve constipation.(viii) No food, drink and tobacco should be taken in a place Tetraethyl Lead where there is a risk of lead poisoning - special rooms should be provided for this in factories. Exposure to high concentrations of vapour of leaded petrol,(ix) Personal cleanliness should be ensured by providing especially in hot weather, is responsible for an acute form of bathing and washing facilities. lead poisoning (lead encephalopathy). In industry this hazard(x) Health education to avoid dusts and fumes of lead being occurs by spillage in petrol filling sheds/holds/barges with inhaled or ingested. inadequate ventilation, inhalation from clothing saturated(xi) Medical surveillance : Pre-employment medical scrutiny of with petrol from spillage and splashing and absorption the prospective workers in the hazardous process should through the skin, which is relatively sight. In some cases a include the history of previous exposure to lead and chronic form of lead poisoning occurs. Proper ventilation of the elimination of those with a positive history of symptoms shed is important. The operation of filling should be carried of lead poisoning. Quarterly medical examination during out in the open air. Exhausted fans may be necessary. Special employment with attention paid to the loss of weight, precautions must be adopted when containers are loaded in gastrointestinal symptoms, weakness of wrist muscles and the holds of the barges. Only containers in sound condition blood picture, removal from exposure should be followed should be accepted for loading and care should be taken in the • 1282 •
  16. 16. storage of the containers. The holds of the barges /tanks should frequently. Shower bath and a change of clothing should followbe provided with adequate ventilation. Short shifts at frequent the day’s work. All cuts, abrasions and other injuries on handintervals during the work and overall turnover of the labour, so and forearm should be protected by adhesive strapping beforethat each man is employed for one week in four on this work, starting work. The forearm should be inspected twice a weekare essential preventive measures. Other precautions are the and any breach of continuity of the skin should be immediatelysame as have been described under lead poisoning with the reported to the factory doctor. A protective ointment should becurrent trend on use of unleaded petrol; it is presumed that applied in the nostrils.toxicity due to this cause will be on the decline. Metal Fume FeverPhosphorous It is an transient illness and is commonly known as ‘BrassWhite Phosphorus (WP) Founders Ague’ ‘Zinc Fever’ or ‘Metal Chill’. It follows the inhalation of high concentrations of finely dispersed zincWhite phosphorus (WP) is being used in smoke producing or brass fumes, usually in the form of oxides. After heavyammunition. After white phosphorus exposure burnt skin is exposure, the nose and throat feel dry and sore giving rise towashed with 5 % sodium bicarbonate and 3 % copper sulphate a dry cough. In a few hours, the symptoms appear. There isin 1 % hydroxy ethyl cellulose. Phosphorus particulars become shivering which may last for some time and this is followed bycoated with black cupric phosphide allowing easy identification. profuse perspiration, the picture simulating that of an attackCopper sulphate also decreases rate of underlying tissue. Since of malaria. Considerable prostration follows the attack, but byblackened particles continue to elicit tissue injury, they can the next morning recovery is almost complete. Some degree ofbe removed. Of late, copper sulphate is found to be toxic and insusceptibility is produced by low - grade inhalation but issystemic copper poisoning can manifest as vomiting, diarrhea, lost in 48 hours. Workers therefore, are likely to suffer moreoliguria, haematuria, hepatic necrosis and cardio - pulmonary on Monday morning; Metal fumes should be eliminated bycollapse. proper exhaust ventilation. When conducting replacement orMercury transfer medical examinations, cases with a history of chronic bronchitis, asthma or any other respiratory trouble should beMercury Fulminate withheld.It is a brownish yellow, heavy, crystalline solid prepared bythe action of alcohol on mercuric nitrate. The chief hazard Mineral Oilsis dermatitis affecting those who are employed in filling Mineral oils are insoluble and soluble. The insoluble ones areoperations where a fine dust is raised, which comes in contact used mainly as lubricants for cutting tools and the soluble oneswith the naked skin. The susceptibility of some individuals are used as cooling agents. Cutting oils have the property ofmay not enable them to withstand exposure even for a day. The defattening the skin. They also plug the pores of the skin andexposed parts of the body become erythmatous accompanied form comedones. After some days of use they may contain steelby violent itching, swelling and oedema of the face, eye - slivers, which may injure the skin and thus start dermatitislids, ears, neck and forearms. Teeth become black owing to affecting the forearm and thigh, small blackheads due tothe formation of mercuric sulphide. Cleanliness of the plant blocking of the sebaceous glands appear in these important. All precautions as for a lead factory should be Preventiontaken. Exhaust ventilation with fitting overalls, aprons, rubbergloves, and if necessary respirators as well. Additional hand Cleanliness of persons, their clothes and machines should bewashing facilities should be provided (26 - 31). ensured by the provision of adequate washing and shower bath facilities. suitable industrial cleaners should be placedChromium at convenient location in the washroom. Clean rags or cottonChromic Acid and bichromates of sodium and potassium are waste free from silver should be provided. Time should beused in chromium plating of metals, manufacture of explosives allowed for workers to carry out thorough cleansing, changeand for tanning of leather, characteristic chrome ulcers occur of clothes and dressing. Those who give a previous history ofon nail beds and the nasal septum. They are small, deep ulcers dermatitis should be excluded by pre placement examination.varying in size from the head of a matchstick to the end of a Persons suffering from seborrhea, acne and excessive sweatinglead pencil. The tissues around the ulcers are heaped up and should be prohibited from employment appear, the personare covered by crusts. They may cause perforation of the nasal should be temporarily withdrawn from the process and re -septum. The ulcers are as rule not painful but heal very slowly employed when the skin condition clears up.(25 - 31). TreatmentPrevention The treatment is usually by soothing lotions or cream likeMechanical lateral exhaust ventilation should be provided for calamine. Barrier creams may help in getting the skin of thethe removal of the vapour and spray at the point of origin. The beginners slowly conditioned to the contact with cutting oilsfloor of rooms containing chrome baths should be impervious, but cannot serve as a permanent protective measure for personsmaintained in good condition and flushed out daily. Suitable whose skins are excessively sensitive.rubber gloves, aprons and other protective clothing should Benzenebe provided and maintained properly. Water taps should beinstalled in workplaces, to enable the workers to wash hands This is colourless aromatic hydrocarbon with a characteristic • 1283 •