Industrial Hygiene

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INDUSTRIAL HYGIENE – A few Pointers By : Dr. Sam A. Thamby Faculty of Pharmacy AIMST University ( Malaysia )


Industrial hygiene is the science of anticipating , recognizing , evaluating , and controlling workplace conditions that may cause workers' injury or illness . Industrial hygienists use environmental monitoring and analytical methods (to detect the extent of worker exposure) and utilize various methods to control potential health hazards. HISTORY 4 th century BC : Hippocrates noted lead toxicity in the mining industry . 1 st century AD : Pliny (a Roman scholar) perceived health risks to those working with zinc and sulfur . He devised a face mask made from an animal bladder to protect workers from exposure to dust and lead fumes. 2 nd century AD : Galen (the Greek physician), accurately described the pathology of lead poisoning and also recognized the hazardous exposures of copper miners to acid mists .


1556 (Germany) : Agricola – his book  De Re Metallica – described the diseases of miners and prescribed preventive measures. (The book included suggestions for mine ventilation and worker protection, discussed mining accidents, and described diseases associated with mining occupations such as silicosis). 1700 (in Italy) : Bernardo Ramazzini (‘father of industrial medicine’) published the first comprehensive book on industrial medicine,  De Morbis Artificum Diatriba (The Diseases of Workmen). The book contained accurate descriptions of the occupational diseases of most of the workers of his time . Ramazzini greatly affected the future of industrial hygiene because he asserted that occupational diseases should be studied in the work environment rather than in hospital wards .


1743 : Ulrich Ellenborg published a pamphlet on occupational diseases and injuries among gold miners. Ellenborg also wrote about the toxicities of carbon monoxide, mercury, lead, and nitric acid. Early 20th century (USA) : Dr. Alice Hamilton led efforts to improve industrial hygiene. She observed industrial conditions first hand and presented evidence that there was a correlation between workers’ illness and their exposure to toxins . She also presented definitive proposals for eliminating unhealthful working conditions.


Industrial Hygienists (IHs) are trained to anticipate , recognize , evaluate , and recommend controls for environmental and physical hazards that can affect the health and well-being of workers . IHs play a major role in developing and issuing standards to protect workers from health hazards associated with toxic chemicals, biological hazards, and harmful physical agents . Industrial hygienists analyze, identify and measure workplace hazards or stressors that can cause sickness , impaired health , or significant discomfort in workers through chemical, physical, ergonomic, or biological exposures .


How do IH's Recognize and Control Hazards ? Engineering , work practice , and administrative controls are the primary means of reducing employee exposure to occupational hazards. Engineering controls : reducing or removing the hazard at the source or isolating the worker from the hazard source (mostly refers to the instruments/devices ). Work practice controls : alter the manner in which a task is performed ( refers to the process/procedure ). Work practice controls include…. (1) following Standard Operating Procedures (SOP) that minimize exposures while operating production and control equipment; (2) regular inspection and maintenance of process and control equipment; (3) implementing good house-keeping procedures ; (4) providing good supervision and (5) mandating practices to be prohibited (eating, drinking, smoking, chewing tobacco or gum, and applying cosmetics in regulated areas).


Administrative controls : include controlling employees' exposure by scheduling production and workers' tasks , or both , in ways that minimize exposure levels . E.g., the employer might schedule procedures with the highest exposure potential during periods when the fewest employees are present. Appropriate respiratory equipments must be used… w hen effective work practices and/or engineering controls are not feasible to maintain the Permissible Exposure Limit ; w hile ‘controls’ are being implemented; in cases of emergencies; Personnel Protective Equipment ( PPE ) such as gloves , safety goggles , helmets , safety shoes , and protective clothing are also be required. To be effective, personal protective equipment must be individually selected , properly fitted and periodically refitted ; properly worn ; regularly maintained ; and replaced as necessary .


JOB HAZARDS Include air contaminants , chemical , biological , physical , and ergonomic hazards . Air Contaminants Either particulate or gas and vapor contaminants. Most common particulate contaminants include dust, fumes, mists, aerosols, and fibers. Dust : (solid particles formed or generated from solid organic or inorganic materials by reducing their size through mechanical processes such as crushing, grinding, drilling, abrading or blasting). Fumes : formed when material from a volatilized solid condenses in cool air. Mists : are generated by liquids condensing from a vapor back to a liquid or by breaking up a liquid into a dispersed state such as by splashing, foaming or atomizing. Aerosols : are also a form of a mist characterized by highly respirable , minute liquid particles . Gases : formless fluids that expand to occupy the space or enclosure in which they are confined. Egs.: acetylene, nitrogen, helium, argon; hydrogen sulfide ; carbon monoxide (generated from by its use as a reducing gas in heat treating processes).


Chemical Hazards Harmful chemical compounds in the form of solids, liquids, gases, mists, dusts, fumes, and vapors ; Exert toxic effects by inhalation (breathing), absorption (through direct contact with the skin; skin irritation), or ingestion (eating or drinking). Airborne chemical hazards exist as concentrations of mists, vapors, gases, fumes, or solids . Degree of worker risk (from exposure to any toxin) depends on… nature and potency of the toxic effects magnitude and duration of exposure .


Biological Hazards Include bacteria , viruses , fungi , and other pathogens that can cause acute and chronic infections (by entering the body either directly or through breaks in the skin). Industrial processes dealing with plants, animals, biological samples and pathogens expose workers to biological hazards. Effective personal hygiene (proper attention to even minor cuts and scratches, especially those on the hands and forearms), helps keep worker risks to a minimum. Workers should practice proper personal hygiene (mainly hand washing); Site : should provide proper ventilation , proper PPE (gloves and respirators), adequate infectious waste disposal systems , and appropriate controls (isolation in instances of contagious diseases such as TB).


Physical Hazards Include excessive levels of ionizing and nonionizing EMR, noise, vibration, illumination, and temperature . In occupations where there is exposure to ionizing radiation, time , distance , and shielding are important in ensuring worker safety. Danger from radiation increases with the amount of exposure time ; (shorter the time of exposure, the lesser the radiation danger). Distance : can be estimated by comparing the squares of the distances between the source and the worker . (Eg.: if worker is 10 feet from a source, the radiation is 1/100 of the intensity than when the worker is at 1 foot from the source). Shielding : Greater the protective mass between a radioactive source and the worker, the lower the radiation exposure . *** Laser radiation cannot be controlled effectively by imposing time limits . It can be hazardous even in a single exposure of a minute . Increasing the distance from a laser source may require miles before the energy level reaches a point where the exposure would not be harmful.


Noise can be controlled by… installing equipment and systems that operate quietly ; enclosing or shielding noisy equipment; equipment is properly maintained (with all worn or unbalanced parts replaced regularly); mounting noisy equipment on special mounts to reduce vibration; installing silencers and/or mufflers ; installing sound barriers at work stations.


Ergonomic Hazards Ergonomic problems arise due to technological changes such as increased assembly line speeds, adding specialized tasks, and increased repetition; poorly designed job tasks. Ergonomic hazards: eye strain , repetitive motion (and shocks ), and heavy lifting problems . Improperly designed tools or work areas also can be ergonomic hazards. Repetitive motions or repeated shocks over prolonged periods of time (sorting, assembling, and data entry) can often cause irritation and inflammation of the tendon sheath of the hands and arms , a condition known as Carpal Tunnel Syndrome . Ergonomic hazards can be avoided by… effective design of jobsite ; better designed tools or equipment ; appropriate engineering controls (e.g., re-designing work stations, proper lighting, quality tools and equipments);



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