Industrial Hygiene; Is defined by the American industrial hygiene association as “that science and art devoted to the anticipation, recognition, evaluation, and control of those environmental factors or stresses arising in or from the workplace, which may cause sickness, impaired health and wellbeing, or significant discomfort among workers or among the citizens of the community.” Thus Industrial hygiene deals with the 1) Anticipation- Includes prior knowledge of possible hazards and there ill effect on health 2) Recognition- acceptance ill effect of identified hazards 3) Evaluation – measuring and calculating the degree of hazards by various instruments. Ex. Air sampling and analysis 4) Control measure- Engineering control, administrative control use of PPE education, and training, medical examination. Importance of industrial hygiene?
Improved worker health and increased life expectancy Reduction in the number of people who have to leave employment early through injury
or illness Lower social and healthcare costs as well as maximizing worker potential More efficient working processes with technological improvements and increased
productivity. Industrial hygiene attempts to eliminate or minimize the exposure of environment or work hazards on human or public health by engineering control, administrative control and good housekeeping and keep the workplace and environment free from pollution.
RECOGNIZING AND CONTROLLING HAZARDS Industrial hygienists recognize that engineering, work practice, and administrative controls are the primary means of reducing employee exposure to occupational hazards. Control measure can be applied at following three level. 1) At source Substitution Change of process or technology Enclosure of process ( Barrier) Isolation ( by space or time) Wet method ( Water Blasting) Local exhaust ventilation Waste disposal
Good housekeeping 2) At Path Providing exhaust ventilation Increasing distance between source and receiver Dilution mechanical ventilation Good housekeeping and maintenance. 3) At Receiver Personal hygiene method (Washing, bathing, good diet, No smoking) USE of PPE Personal monitoring device Rotation of worker Training and education Medical examination and follow up. Engineering controls minimize employee exposure by either reducing or removing the hazard at the source or isolating the worker from the hazard. Engineering controls include eliminating toxic chemicals and substituting non-toxic chemicals, enclosing work processes or confining work operations, and the installation of general and local ventilation systems. It also includes Segregation- shifting potentially dangerous process to a segregated or enclosed area. Substitution- Highly toxic material should be replaced by less hazardous material and process. House-keeping-particular where dust is the problem Work practice controls alter the manner in which a task is performed. Some fundamental and easily implemented work practice controls include (1) Changing existing work practices to follow proper procedures that minimize exposures while operating production and control equipment; (2) Inspecting and maintaining process and control equipment on a regular basis; (3) implementing good housekeeping procedures; (4) Providing good supervision; and (5) Mandating that eating, drinking, smoking, chewing tobacco or gum, and applying cosmetics in regulated areas be prohibited. Administrative controls include controlling employees' exposure by scheduling production and tasks, or both, in ways that minimize exposure levels. For example, the employer might schedule operations with the highest exposure potential during periods when the fewest employees are present.
When effective work practices or engineering controls are not feasible or while such controls are being instituted, appropriate personal protective equipment must be used. Examples of personal protective equipment are gloves, safety goggles, helmets, safety shoes, protective clothing, and respirators. To be effective, personal protective equipment must be individually selected, properly fitted and periodically refitted; conscientiously and properly worn; regularly maintained; and replaced, as necessary It also Include Education and training, regular inspection and monitoring for physical and chemical health hazard, shift Incharge
safety report book, detail examination of industrial
hygiene and environmental aspect of important health, safety, and environment hazards. --------------------------------------------------------------------------------------------AREA OR WORKPLACE OR WORK ENVIROMENTAL MONITORING 1) Area Monitoring is done for the determination of concentration in the workplace area or in the breathing zone of the employee. 2) Area monitoring can be done for 8 Hrs. 15 Min or instantaneous. 3) The result is the compared with the exposure indices such as TLV, STEL, and ceiling limits. 4) The purpose of workplace monitoring is to identify the airborne concentration of the contaminant in the worst case situation. 5) Workplace monitoring is also used to determine background level of contaminant in a work room. 6) Workplace monitoring can be conducted by keeping sampling device near to contaminant emission area. 7) Continuous Workplace monitoring is used to detect fugitive emission, leaks, failure and equipment malfunctioning before employer exposure occurs. 8) First Permissible limits have prescribed by standard and kept as a target. Then actual level parameters of working environment should be measured and compared with the target. If the measured values higher than standards then control measure is to be applies to bring them down to permissible level. 9) Following factor should be consider while workplace monitoring Physical, biological, meteorological factors Hazards of work, working condition, methods Raw material, equipment, process, waste disposal etc. -----------------------------------------------------------------------------------------------------------BIOLOGICAL MONITORING
1) Biological monitoring is defined as the represent and regular measurement and assessment of agents or their metabolites either in blood, urine, secreta, expired air or combination of this to evaluate exposure and health risk compared to an appropriate reference. 2) The air monitoring provides airborne concentration of contaminant, not necessary the absorption of contaminant by an exposed individual. Biological monitoring has distinct advantage over air measurement, because it is the absorb chemical, and/or its biomarker, is measured. 3) Biological biochemical samples are the blood, urine, breath, plasma, body fluid, sweat, hair, nail saliva etc. 4) This above factor is analyzed to measure any change due to absorption of toxic material. 5) Measurement of quantity deposition OR effect of lead, mercury cadmium and the fluoride in the blood and urine give their health effects. 6) By establishing base line level, such monitoring required necessary environmental control and improved in work method. 7) Biological exposure indices BEL are applied to biological monitoring and TLV to air monitoring. 8) Biological monitoring is not the replacement of any other form of monitoring. It is complementary, it give the evaluation of individual exposure. 9) Biological monitoring offers other advantages:1. It is an attempt to measure the parameter most directly related to potential health effects. Results can aid in formulating a more refined estimate of risk of illness secondary to exposure. 2. Non-occupational exposures and individual variability are assessed. 3. Multiple exposures and other routes of exposure, such as dermal and ingestion, can be evaluated. ---------------------------------------------------------------------------------------------------------DEFINE FOLLOWING TERM 1) Dust 2) Mist 3) Fumes
4) Smoke 5) Vapor 6) Aerosols
==refer from Book page no 24-13, 14== Q) What are the effects and control measure of following hazards? IONISING RADIATIO EFFECTS
Ionising radiation means the electromagnetic radiation which consist of Alpha, Beta,
X-rays, Gama radiation Human studies have shown that exposure to ionizing radiation can cause
carcinogenic, teratogenic, mutagenic effect. It can also cause skin cancer, ulceration, dermatitis, cataract, damage to bones and blood Human body always having the capacity of generation of new cell by replacing dead or damaged cell. But due to long period of exposure in ionizing radiation can cause the destruction capacity of reproduction of new cell. Such effect known as biological effect. Biological effect is the destruction of reproduction capacity of cell or carcinogenic effect (cancer) which is difficult to cure. When radioactive contamination or irradiation is likely to exceed the maximum permissible limit such overexposure known as radiation accident. Control measure Shielding of body portion specially blood forming tissue and intestine. Barrier at the path source and human body by high density material like lead and
concrete wall Low dose rate OR fractionate of the dose and decreasing the dose level Reducing the exposure time Increasing the distance from source Using sealed source of radiation Pre and post medical examination of employees Continuous monitoring and preventing method by engineering control safe disposal of radioactive waste in case of external irradiation, measurement of exposure in the body and the space,
should soon be carried out to decide a course of action In case of radioactive contamination, urgent treatment is essential. If the whole body irradiation is more than 100 rem, then the person should
immediately transferred to the specialized hospital. If the ionizing radiation can be neutralized or interrupted then the decontamination is the best safety measure to protect man against possible hazards of direct and indirect radiation. Method of decontamination
Mechanical Decontamination- removal of radioactive layer by scrubbing, shot blasting, washing by water Physical decontamination- evaporation, dilution, filtration, ultrasonic technique Chemical decontamination- treating with acid, alkali, ion exchange resin.
-----------------------------------------------------------------------------------------------NON-IONISING RADIATION Though the non-ionizing agent is non-hazardous, its prolonged exposure may cause the ill effect to health. It include infrared radiation, ultraviolet, visible light, microwave, radiowaves, laser power, frequency, and radar waves INFRARED RADIATION Source- Infrared radiation is very common in glass industry, hot
furnaces, arc process.
Effects Over exposure produces some discomfort Eye may suffer injuries OR general discomfort to other part of the body. In some cases it may result to cataract. Control measure Protection measure against the radiation includes the placement of reflective screen of polished aluminum shield near to the source. Use of enclosure, shielding, eye protection, and safe distance are mainly safety measure. ULTRAVIOLET RADIATION Source- Welding process, direct sunlight. Effects Deep burns may be endured without immediate discomfort. This radiation readily absorbed in human tissue. As a results of superficial injuries to be produce to the skin and eye. Higher exposure can cause eye damage (ocular) and skin damage (Dermatological) Solar or UV radiation from artificial source may cause skin pigmentation. Long exposure to hottest sunlight may cause skin cancer. This must be avoided. Control Measure Shielding of UVR source, use of eye goggle, protective clothing, absorbing and reflecting skin creams. Local exhaust ventilation may also be used as an effective means.
VISIBLE LIGHT Source- Sun, Laser beam, arc welding highly incandescent and artificial light source such as high intensity lamp, projector bulb, fluorescent tube etc. Effects May cause ratinal injury due to peak brightness. Exposure to glair can cause fatigue to eye, iritis, and blepharism. Control Measure Provide adequate quantity and quality of light or illumination. POWER FREQUENCY EFFECTS The main hazard of high voltage lines and low frequency equipment are shocks and current. Extremely low frequency (ELF) radiation can produce electric field that induce electric current in the body. CONTROL MEASURE Protection from ELF is possible by shielding electric field by conducting surface. Use PPE like electrically conductive clothing. RADAR (Radio Detection and Ranging) Hazards
Electric hazards, fire hazards from flammable gaseous Toxic hazards Thermal effect of electromagnetic radiation X-rays from high voltage tube Material handling hazards
Control Measure
Standing near to antenna should be avoided Should not directly to radar beam Keeping safe distance from the beam Photoflash bulb should be properly packet to avoid ignition hazard. Pre and post medical examination of radar worker.
---------------------------------------------------------------------------------------------Q) Permissible limits of exposure? Permissible exposure limit (PEL) is the legal limit in the U.S. for maximum concentration of any chemical in the air to which a worker may be exposed continuously for eight hours without any danger to health and safety. PEL is established by the Occupational Safety and Health Administration (OSHA). ===Page 24-17 of the book==== --------------------------------------------------------------------------------Q) Explain personnel sampler Personal sampling is used to both detect and measure exposures. It is done to
determine the quality of the air the worker is breathing or would breathe if not protected. Samples are usually collected by placing a battery-operated air pump on the wearer's belt and clipping a collection tube or filter in the breathing zone, usually on the collar
near the nose. Air from the environment is pulled into the collection device where the contaminants are trapped, and then the sample is sent to a laboratory for analysis. Another method of collecting personal air samples is through the use of a passive dosimeter. This device is a badge clipped to the worker's collar which collects a sample without using a pump. Purpose To determine and types and concentration of exposure due to the health hazards to worker. To determine the types and effectiveness of the control measure provided, any change if necessary in them and new control measure to be provided. To investigate complaints. For research purpose. Advantages of personal air sampling: It is the most accurate measurement of worker's actual exposure, because it goes where the worker goes and can be placed in the breathing zone (near the nose). Results can be converted to a TWA or STEL and compared with the OSHA and ACGM values. Personal air monitoring documents exposure.
Disadvantages of personal air sampling: Laboratory analysis of the sample may take 1-14 days. Sampling provides no data concerning peak or ceiling exposures if collected over several hours. Generally sampling requires knowledge of the specific chemical in the air. Preparation is necessary so that the equipment is ready to be used. Q) Dose response Relationship? Dose response relationship is useful to evaluate toxic effect Normally test carried on animal are subject to lower to higher doses and their death rate is observed It can be plotted in figure shown in below 100 Response 50 5
LDs
LD50
LD100
Dose or concentration Doses are expressed in mm/kg of body weight OR /mm2 OR skin surface area OR /m3 of the respired air of the test animal Duration is also noted It can express as the product of concentration and the time of exposure…. CXT=constant The CT value can be used mathematically to derive approximate combination of concentration of a chemical and time that would produce the similar effect It can be useful for in predicting the safe limit for airborne contaminants in environment. Safe limit are set so that the combination of concentration and the time duration are below the lowest harmful test. -------------------------------------------------------------------------------------Q) Threshold Limit Value? And explain its signification? OR Q) Concept of TLV with various categories?
Threshold Limit Value (TLV) is a registered and reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH).
It is an occupational exposure value
recommended by ACGIH to which it is believed nearly all workers can be exposed for lifetime without affecting health. Generally defined in three different way Ceiling Limit (C) – The concentration that must not be exceed at any part of workday. If instantaneous monitoring is not feasible, the ceiling shall be accessed as a 15 min TWA exposure, which shall not be exceeded at any time over a work day Short Term Exposure Limit (STEL) - The maximum concentration to which workers may be exposed for a short period of time. Time-Weighted Average (TWA) – The average concentration to which workers may be exposed for normal 8 hours workday. Significance--------------------------------------------------------------------------------------Q) Industrial Fatigue? Definition-
Mental
or
physical
exhaustion
resulting
from
performing required work-
related activities that leads to a diminished capacity for performing the work. Generally due to the poor working conditions or demanding job requirements. Effects1. It leads to loss of efficiency. 2. It results in more or less complete loss of responsiveness of tissue. 3. It may be termed as the reduced capacity of work resulting from work itself. 4. It is considered as state of ‘lack or interest’ in not only work but in other activities too. Fatigue may be caused due to the following reasons: 1. Longer hours of continuous work without rest pauses may cause fatigue because muscles will be tired after long work.
2. Unsatisfactory working environment like insufficient light insanitation, congestion, noise elevated temperatures etc. 3. Fatigue may also be caused by personal reasons such as family tension, bad health etc. 4. There may be faulty design of machines and equipment which leads to wastage of energy of workers on them. 5. The complexity or production process may also put more loads on workers resulting into fatigue. 6. The workers may not be properly placed on jobs as per their skill levels. 7. The harsh attitude of supervisor may also result in fatigue of workers. 8. Inconvenient and awkward posture of worker (required for some particular jobs) i.e., standing or bending for longer periods may also be the cause of fatigue. Methods of Reducing Fatigue: 1. Rest pauses: When workers continue to work for longer periods then they; feel tired and need some rest. Rest pauses are of great importance in reducing fatigue as well as monotony. Rest pauses should be provided in such a way that workers feel relieved after working for some hours. A well planned rest pauses schedule will be of .great help in reducing fatigue. 2. Less hours of work: Longer hours of work are the main cause of fatigue. The hours of work should be reduced to that optimum level where workers are able to keep up their working speed. The factories act in India allows only 48 hours a week for adult workers and it should be followed strictly. 3. Proper lighting: Poor illumination is an important cause of disturbance and fatigue. The work place should be properly lighted so that workers are able to work without burdening their eye sight and brain. 4. Improving environmental conditions: The humidity, temperature and ventilation influence workers at work. A proper balance of temperature, humidity should be maintained to make the work place comfortable and worth working so that fatigue is reduced. 5. Reduction of noise:
Undesirable noise will cause fatigue. It may also cause muscular tension. Unnecessary noise should be curbed to its, minimum level. Lower noise levels increase productivity of workers by reducing fatigue, removing cause of irritation. 6. Proper selection of employees: A wrong selection of employees and their placement may also be a reason for fatigue and monotony. A job may require more physical input than worker has. In such situations the worker will feel fatigued after short duration of work. A square peg in a square hole will help in reducing fatigue and boredom so proper selection shall help in this regard. 7. Job rotations: Sometimes workers start feeling bore and tired while working repeatedly on the same job. If job rotation a is provided it will avoid boredom and fatigue. 8. Counseling of employees: Anxieties and worries may be the main cause of fatigue with some workers. There may be job dissatisfaction domestic problem etc. the officers of personnel department should counsel the employees and help them in solving their problems -------------------------------------------------------------------------------------------------------Q) INDUSTRIAL DERMATITIS- “Causes and Prevention”? Industrial dermatitis is skin disease primarily caused by the industrial environment. It is the commonest occupational disease in industrialized countries. CAUSES Substances which might cause occupational dermatitis include cleaning products, organic solvents, metalworking fluids, cement, adhesives, other chemicals, and even certain plants. There are two main types of dermatitis caused by contact with hazardous substances at work. A) Irritant contact dermatitis
This is the more common type of work-related dermatitis which can occur when a person comes into contact with an irritant over a prolonged period of time. Substances known to cause irritation include:
Machine oils
Detergents
Perfumes
Toiletries
Disinfectants
Cosmetics
B) Allergic contact dermatitis This usually occurs when the body’s immune system has an abnormal reaction to a substance. Common causes of allergic contact dermatitis include:
Rubber / latex
Glues
Adhesives
Preservatives
PREVENTIONWorkers should: Read and understand the nature of Material Safety Data Sheets (MSDS) to be informed of any health hazards and know the precautions to take. Phrases such as “may cause skin sensitization” or “skin irritant” indicate that the substance can cause dermatitis. Check whether there is a safer alternative, if using a chemical that can cause dermatitis. A good example is water-based paints, cleaner or inks instead of solvent-based products. Use barrier creams and personal protective clothing such as gloves, aprons and chemical suits as a last resort to prevent skin contact and / or absorption. Ensure that the correct cream is used for protection, as there are different barrier creams for water soluble agents and for solvent-based agents.
Remove any contaminated clothing quickly. Immediately wash skin that has been in contact with skin irritants or sensitizers with large amounts of warm clean water and a mild moisturizing soap. Never wash hands with solvents such as Varsol or gasoline. Instead, use mild soaps and ensure that skin is frequently moisturized with hand creams. Seek medical attention as soon as possible, if any changes in skin are noticed while at work or after using substances. Early diagnosis and advice is essential in preventing occupational dermatitis. Occupational Dermatitis Employers should: Ensure the workplace is in compliance with all WHMIS legislation. MSDS’s must be readily available on site for all controlled products being used. Change the way processes are done if possible to effectively reduce skin contact with dermatitis agents. For example, automated mixing instead of hand mixing substantially reduces the chance of skin contact. Provide appropriate barrier creams or personal protective equipment as a last resort. In the case of an emergency have an eyewash station and deluge shower for cleansing the eyes, face and skin after contact with skin irritants or sensitizers. Provide adequate hygiene facilities on site for workers to wash hands and face at the end of the job, before eating, drinking or smoking and after using the toilet. Q) What is aerobic work capacity? How way of its determination? The evaluation of a worker made from his physical work capacity i.e...e his maximum O2 intake or aerobic capacity and other physiological function under classified work load. The physical work capacity of an individual is measured by the physiological work capacity. This has been calculated physical fitness and maximum O2 uptake capacity, Purpose- this is important for many purposes such as selection of right jobs, disability, evaluation, rehabilitation of disable and diseased worker. Factor affecting aerobic capacity
Ventilation of lung O2 carrying capacity of blood Unloading of O2 at the tissues Minute volume of the Heart
Assessment of work capacity A) Physiological Test (Step Test)
The step test developed in Harvard fatigue laboratory, USA. To evaluate physical fitness of an individual The person has to be step up and step down on a stool of height 45 cm at the rate of
30 complete steps per minute. This process carries out for next 5 minute. The rate of stepping is regulated by metronome. After exercise is over, person is seated and his pulse rate is counting for 1 min. Fitness score is calculated as follow Duration of stepping in second X 100 Score= 5.5 X (half min recover pulse count recorded)
Grading score Below
above
50 50-65 65-80 80-90 90
Poor Low average High average Good Excellent
B) Pulmonary Function Test (8 Marks) Abstract Pulmonary function tests are valuable investigations in the management of patients with suspected or previously diagnosed respiratory disease. They aid diagnosis, help monitor response to treatment and can guide decisions regarding further treatment and intervention. The interpretation of pulmonary functions tests requires knowledge of respiratory physiology. In this review we describe investigations routinely used and discuss their clinical implications. Introduction Pulmonary function tests (PFTS) are an important tool in the investigation and monitoring of patients with respiratory pathology. They provide important information relating to the large and small airways, the pulmonary parenchyma and the size and integrity of the pulmonary capillary bed. Although they do not provide a diagnosis per se, different patterns of abnormalities are seen in various respiratory diseases which help to establish a diagnosis. We describe the indications for performing PFTS, describe abnormal results and correlate these with underlying pathology.
Procedure Pulmonary function tests (PFTs) are a group of tests that measure how well your lungs work. This includes how well you're able to breathe and how effective your lungs are able to bring oxygen to the rest of your body. Your doctor may order these tests: if you're having symptoms of lung problems. This is the simplest method where ergometer is used to measure exhaled air volume and compare it with standard average values. Physical fitness and any disorder is calculated Spirometry measures airflow. By measuring how much air you exhale, and how quickly, spirometry can evaluate a broad range of lung diseases. I In a spirometry test, while you are sitting, you breathe into a mouthpiece that is connected to an instrument called a spirometer. The spirometer records the amount and the rate of air that you breathe in and out over a period of time. Why the Test is performed?
Pulmonary function tests are done to: Diagnose certain types of lung disease (such as asthma, bronchitis, and emphysema) Find the cause of shortness of breath Measure whether exposure to chemicals at work affects lung function Check lung function before someone has surgery It also can be done to: Assess the effect of medication Measure progress in disease treatment --------------------------------------------------------------------------------------------------
Q) Describe the main route of entry of toxic substance in human body? Following are the four main route of entry of toxic material into human body A) Absorption through skin The significant quantity of this compound may enter the body though the skin either as a result of direct accidental contamination OR indirectly when the material has been spilled on the clothing Using the industrial solvent for removing the grease and dirt from the hands and arms is a source of dermatitis. Some solvent penetrate the intact skin, get into the blood stream and produce ill effect on the blood. Example-aniline, phenol, nicotine
While manufacturing, handling, and spraying pesticide, liquid splashes may enter through skin and cause toxic effect. Other chemicals (e.g., nitric acid) corrode the skin causing burns and blisters. Chemicals pass through the skin into the blood. If the skin is irritated, damaged, or punctured, absorption is increased. B) Absorption through Gastrointestinal Tract (GIT) (Ingestion or Digestive tract) Use of contaminated and dirty vessels used for eating and drinking is the most common route of injection Accidental swallowing of chemical is also possible. Contaminated food, drinks, beverage should not be eaten without washing hand and mouth properly. C) Absorption Through Lungs (Inhalation or Respiratory Tract) The inhalation of contaminant air is the most important means by which the occupation poisons enter into the body. From 8 hour working in a day, a man may breadth 10 cubic meters of air. Any poisonous material present in the respired air offers a serious threat. As we breathe, we inhale what is in the air. If dusts, particles, and chemicals are in the air we breathe, they may be deposited in the lungs or cross into the bloodstream along with oxygen. Inhaled dusts and fibers caught in the nose and airways are moved out of the nose and airways on an "escalator" made of hair-like cilia and mucus and then swallowed. Inhalation is the major way that toxic substances get into your body. Good housekeeping, Ventilation, local exhaust ventilation, use of appropriate while handling toxic substance is primary needs. D)
InjectionThe fourth route of entry is the direct injection of the material into the blood stream By needle it can be inserted into the skin, muscle or other part of the body. Mostly this route is used to inject the material into laboratory animals.
---------------------------------------------------------------------------------------------------------Q) How will u access the airborne concentration of the dust? How it help in protecting of health of the worker? --------------------------------------------------------------------------------------Q) Chemical Hazards of Dust fumes and aerosols and their preventive measures? Dust hazards
While handling building material, workers can be exposed to four type of dust which by inhalation can cause following lung disease. Silicosis- Silica dust causes fibrotic changes, modulation in both lungs, and shortness of breath, decreased cheat expansion, reduced work capacity, impairment of total lung capacity. The effect is irreversible and no effective treatment is available. Siderosis- Is caused by inhalation of iron dust. Electric arc welding, dry grinding of iron, buffing, shot-blasting, polishing produces iron dust. Coal Worker Pneumoconiosis- - Is caused by inhalation of coal dust. foundry worker are exposed to coal worker dust Byssinosis- Is caused by inhalation of cotton. Textile worker are exposed to cotton dust Preventive measure Know the exposure limit of the dust and refers the 2 nd schedule of factories act. Employ effective measure based on this safe limit and nature of the dust. Elimination- Elimination of dusty process e.g improved casting technique to eliminate dusty fettling process. Substitution- Substitution by a less toxic or non-toxic dust, e.g shot blasting in case of sand blasting, metal moulds in place of sand moulds, glass fibre in place of asbestos insulation. Segregation and enclosure- Enclose the process if the dust generation cannot be prevented. Provide effective dust collector and local exhaust ventilation. Wet Method- Wet method to prevent particles becoming airborne. Powdered material is suspended or dissolved in a liquid. The correct degree of wetting should be maintained and it should not be allowed to dry out. Local exhaust ventilation should apply at source of origin. FUMES HAZARDS Prolonged exposure to welding fumes and gases at high concentrations can cause:
siderosis (iron oxide) metal fume fever (zinc oxide, magnesium oxide, copper, aluminium) nervous system disorders (manganese) irritation of respiratory system eye, nose and throat irritation chest pain kidney damage (cadmium oxide, fluorides) cancer (cadmium oxide, nickel, chromium (VI)) fluid in the lungs (cadmium oxide, fluorides, ozone, nitrogen oxide) dermatitis, eczema (nickel, chromium (VI)) Headaches and dizziness.’
Preventive measure
Ventilation Adequate ventilation must be provided for all welding and allied processes. The combination of general dilution ventilation and local exhaust is the most successful method in controlling welding fumes and gases. Dilution ventilation Dilution ventilation comprises fans such as roof exhaust fans and wall fans. A dilution ventilation system uses large amounts of air to flush out the whole area and dilute contaminants to the concentrations below prescribed limits. Local exhaust ventilation Some welding equipment come equipped with local exhaust ventilation attached to the welding equipment and is designed to remove the fumes and gases close to their point of origin Respiratory protection Respiratory protection should only be used when engineering controls, such as ventilation are not technically and/or economically feasible. In some cases, the combination of both ventilation and respiratory protection may be necessary to reassure that the welders are protected. According to the Standard, a respiratory protection program must consist of the following components: roles and responsibilities, hazard assessment, selection of the appropriate respirators, respirator fit testing, training, use of respirators, cleaning, inspection, maintenance, and storage of respirators, health surveillance of respirator users, program evaluation, and Recordkeeping. Other protective equipment For all welding and cutting operations, welders must wear appropriate eye and face protection, and clothing. Hearing protection may also be required depending on the levels of noise to which welders are exposed.
Medical surveillance program Medical surveillance program, when recommended by a qualified person, must be made available to all workers exposed to welding fumes and gases. AEROSOLS HAZARDS Aerosols containing infectious agents or hazardous materials can pose a serious risk because: Small aerosol particles can readily penetrate and remain deep in the respiratory tract if inhaled. Aerosols may remain suspended in the air for long periods of time. Aerosol particles can easily contaminate equipment, ventilation systems, and human skin. Preventive Measure
Conduct procedures that may produce aerosols in a biological safety cabinet. Avoid overfilling centrifuge tubes so that closures do not become wet. When centrifuging, use sealed tubes and safety buckets that seal with O-rings. Exhaust air from the vacuum lines of high speed centrifuges or lyophilizers should be
filtered. Keep tubes stoppered when vortexing or centrifuging. Allow a few (1-5) minutes for aerosols to settle before opening. When combining liquids, discharge the liquid down the side of the container or as close to the surface of the primary liquid as possible. Avoid splattering by allowing inoculating loops or needles to cool before touching
biological specimens. Using a shielded electric incinerator minimizes aerosol production. Disposable plastic loops and needles may be used. Use a vacuum system for aspirating, rather than pouring off supernatant. Protect vacuum systems from biological aerosols by using an overflow flask and a
cartridge-type filter that is hydrophobic, with a pore size of 0.2 um. Use face shields / eye protection. Q) Explain biological monitoring to prevent the compensation of occupational disease? Advantage of Biological Monitoring to prevent the compensation of occupation disease The purpose of biological monitoring of exposure is to assess health risk through the evaluation of internal dose, achieving an estimate of the biologically active body burden
of the chemical in question. Its rationale is to ensure that worker exposure does not reach levels capable of eliciting adverse effects. Biological monitoring of effects is aimed at identifying early and reversible alterations which develop in the critical organ, and which, at the same time, can identify individuals with signs of adverse health effects. In this sense, biological monitoring of effects represents the principal tool for the health surveillance of workers. It is an attempt to measure the parameter most directly related to potential health effects. Results can aid in formulating a more refined estimate of risk of illness secondary to exposure. Non-occupational exposures and individual variability are assessed. Multiple exposures and other routes of exposure, such as dermal and ingestion, can be evaluated. Q) Explain the preventive and control measure of permissible threshold exposure limit? Preventive measureA) Workplace monitoring B) Biological MonitoringC) Personal monitoring The concentration of the contaminant present in the breathing zone of a potentially exposed employee is quantified by personal air monitoring. The purpose of personal air monitoring is to identify individual exposure and to ensure the regulatory compliances with exposure indices. Personal air monitoring involves the collection of an air sample by a sampling device (dosimeter) worn by a worker.
Control Measures Engineering and work practice controls are the primary methods used to reduce workers' exposure to methylene chloride. Employers must use engineering controls and work practices to reduce employee exposure to methylene chloride to or below the PEL and to maintain exposure at these levels. The only exception is when the employer can demonstrate that this is infeasible and that other controls are necessary. Engineering controls
Examples of engineering controls are local exhaust ventilation, general and special isolation devices, and enclosures. These controls reduce employee exposure in the workplace by either removing or isolating the hazard or isolating the worker from it. By reducing or removing contaminants from the air, engineering controls reduce or eliminate exposure hazards. Work practice controls Work practice controls reduce the likelihood of exposure by altering the way a task is performed. One example is having a worker keep his or her face out of the
methylene chloride vapor zone above a dip tank. Another safe practice is to prohibit employees from eating, drinking, smoking, taking medication, or applying cosmetics inside the work area where methylene chloride is used.
Administrative controls An administrative control removes the worker from exposure. For example, one method of controlling worker exposure to contaminants involves scheduling operations that pose the highest risk of exposure when the fewest employees are present. However, employee rotation -- for example, scheduling several employees to perform work in the exposure area for shorter time limits -- is not an effective way to control methylene chloride exposure. That is because, although it may reduce individual exposure, it may increase the number of employees exposed. For this reason, the standard strictly prohibits employee rotation as a means of compliance with the PELs. ----------------------------------------------------------------------------------------Q) Describe Visual fatigue Causes of Eye Fatigue
Any activity that requires intense use of the eyes -- such as extended amounts of driving or reading -- can cause eye fatigue. These include extended periods of: Reading Writing
Driving
Exposure to bright light or straining to see in dim light can also cause eye fatigue. One of the most common causes of eye fatigue is staring for long periods at digital devices such as: Computer screens Smartphones
Video games
Symptoms of Eye Fatigue
Eye fatigue is associated with uncomfortable and annoying symptoms, such as:
Sore or irritated eyes
Difficulty focusing Dry or watery eyes Blurred or double vision
Increased sensitivity to light Pain in the neck, shoulders, or back
Make changes to your work environment, such as:
Lighting to reduce glare and harsh reflections. Change Use an adjustable chair. Place a document holder next to your computer screen.
------------------------------------------------------------------------------------------------ Q) Explain the types of hazards
Types of hazard
Hazards are generally labelled as one of five types:
Physical hazards are conditions or situations that can cause the body physical harm or intense stress. Physical hazards can be both natural and human made elements.
Chemical hazards are substances that can cause harm or damage to the body, property or the environment. Chemical hazards can be both natural and human made origin.
Electric Hazards-An electrical hazard can be defined as. - a dangerous condition where a worker could make electrical contact with energized equipment or a conductor, and from which the person may sustain an injury from shock; and/or, there is potential for the worker to receive an arc flash burn, thermal burn, or blast injury.
Biological hazards are biological agents that can cause harm to the human body. These some biological agents can be viruses, parasites, bacteria, food, fungi, and foreign toxins.
Psychological hazards are created during work related stress or a stressful environment. A person can be a hazard when he/she is affected psychological disturbance through -stress, shift patterns and also can be a hazard when a person is under the influence of alcohol, illness and lack of training.
Ergonomic Hazard- An ergonomic hazard is a physical factor within the environment that harms the musculoskeletal system. Ergonomic hazards include themes such as repetitive movement, manual handling, workplace/job/task design, uncomfortable workstation height and poor body positioning -------------------------------------------------------------------------------------------------