Biological hazards include bacteria, viruses, fungi, and other living organisms that can cause acute and chronic infections by entering the body either directly or through breaks in the skin. Occupations that deal with plants or animals or their products or with food and food processing may expose workers to biological hazards. Laboratory and medical personnel also can be exposed to biological hazards. Any occupations that result in contact with bodily fluids pose a risk to workers from biological hazards.
In occupations where animals are involved, biological hazards are dealt with by preventing and controlling diseases in the animal population as well as properly caring for and handling infected animals. Also, effective personal hygiene, particularly proper attention to minor cuts and scratches especially on the hands and forearms, helps keep worker risks to a minimum.
In occupations where there is potential exposure to biological hazards, workers should practice proper personal hygiene, particularly hand washing. Hospitals should provide proper ventilation, proper personal protective equipment such as gloves and respirators, adequate infectious waste disposal systems, and appropriate controls including isolation in instances of particularly contagious diseases such as tuberculosis.
Biological agents include bacteria, viruses, fungi, other microorganisms, and their associated toxins. They have the ability to adversely affect human health in a variety of ways, ranging from relatively mild allergic reactions to serious medical conditions, even death. These organisms are widespread in the natural environment; they are found in water, soil, plants, and animals. Because many microbes reproduce rapidly and require minimal resources for survival, they are a potential danger in a wide variety of occupational settings.
This page provides a starting point for technical and regulatory information about some of the most virulent and prevalent biological agents.
Anthrax: Anthrax is an acute infectious disease caused by a spore-forming bacterium called Bacillus anthracis. It is generally acquired following contact with anthrax-infected animals or anthrax-contaminated animal products.
Avian Flu: Avian influenza is a highly contagious disease of birds which is currently epidemic amongst poultry in Asia. Despite the uncertainties, poultry experts agree that immediate culling of infected and exposed birds is the first line of defense for both the protection of human health and the reduction of further losses in the agricultural sector.
Bloodborne Pathogens and Needlestick Prevention: OSHA estimates that 5.6 million workers in the health care industry and related occupations are at risk of occupational exposure to bloodborne pathogens, including human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and others.
Botulism: Cases of botulism are usually associated with consumption of preserved foods. However, botulinum toxins are currently among the most common compounds explored by terrorists for use as biological weapons.
Foodborne Disease: Foodborne illnesses are caused by viruses, bacteria, parasites, toxins, metals, and prions (microscopic protein particles). Symptoms range from mild gastroenteritis to life-threatening neurologic, hepatic, and renal syndromes.
Hantavirus: Hantaviruses are transmitted to humans from the dried droppings, urine, or saliva of mice and rats. Animal laboratory workers and persons working in infested buildings are at increased risk to this disease.
Legionnaires' Disease: Legionnaires' disease is a bacterial disease commonly associated with water-based aerosols. It is often the result of poorly maintained air conditioning cooling towers and potable water systems.
Mold: Molds produce and release millions of spores small enough to be air-, water-, or insect-borne which may have negative effects on human health including allergic reactions, asthma, and other respiratory problems.
Plague: The World Health Organization reports 1,000 to 3,000 cases of plague every year. A bioterrorist release of plague could result in a rapid spread of the pneumonic form of the disease, which could have devastating consequences.
Ricin: Ricin is one of the most toxic and easily produced plant toxins. It has been used in the past as a bioterrorist weapon and remains a serious threat.
Severe Acute Respiratory Syndrome (SARS): Severe acute respiratory syndrome (SARS) is an emerging, sometimes fatal, respiratory illness. According to the Centers for Disease Control and Prevention (CDC), the most recent human cases of SARS were reported in China in April 2004 and there is currently no known transmission anywhere in the world.
Smallpox: Smallpox is a highly contagious disease unique to humans. It is estimated that no more than 20 percent of the population has any immunity from previous vaccination.
Tularemia: Tularemia is also known as "rabbit fever" or "deer fly fever" and is extremely infectious. Relatively few bacteria are required to cause the disease, which is why it is an attractive weapon for use in bioterrorism.
Viral Hemorrhagic Fevers (VHFs): Along with smallpox, anthrax, plague, botulism, and tularemia, hemorrhagic fever viruses are among the six agents identified by the Centers for Disease Control and Prevention (CDC) as the most likely to be used as biological weapons. Many VHFs can cause severe, life-threatening disease with high fatality rates.
Physical health hazards that employees face include excessive levels of ionizing and nonionizing electromagnetic radiation, noise, vibration, illumination, and temperature and humidity extremes. Throughout the rest of this module, we'll briefly look at each of the following common types of physical hazards encountered by employees in the workplace. Industrial hygienists routinely analyze workplaces for these hazards and exposures.
Radiation: In occupations where there is exposure to ionizing radiation, time, distance, and shielding are important tools in ensuring worker safety. Danger from radiation increases with the amount of time one is exposed to it; hence, the shorter the time of exposure the smaller the radiation danger.
Noise: Noise, another significant physical health hazard, can be controlled by various measures. Noise can be reduced by controlling the noise at the source and by controlling exposure to the noise.
Temperature and humidity: Another physical hazard, radiant heat exposure in factories such as steel mills, can be controlled by installing reflective shields and by providing protective clothing.
Illumination: Illumination in the workplace is an important consideration. Inadequate or too much illumination in the work area can cause eye strain. Work environments that are too dark can possibly cause injuries from tripping and falling.
Ergonomics: More injuries and physical disorders are caused by the hazards associated with poor ergonomics. Strains, sprains, repetitive motion injuries, and musculoskeletal disorders are common in the workplace. Unfortunately, OSHA does not have specific mandatory standards that address proper ergonomics.
Radiation includes a wide range of energies forming the electromagnetic spectrum, which is illustrated to the right. The energy of the radiation shown on the spectrum to the right increases from left to right as the frequency rises. The spectrum has two major divisions:
Time, distance, and shielding actions minimize your exposure to radiation in much the same way as they would to protect you against overexposure to the sun:
Exposure to high levels of noise can cause permanent hearing loss. Neither surgery nor a hearing aid can help correct this type of hearing loss.
Noise-induced hearing loss limits your ability to hear high frequency sounds, understand speech, and seriously impairs your ability to communicate. Noise may be a problem in your workplace if:
OSHA sets legal limits on noise exposure in the workplace. These limits are based on a worker's time weighted average over an 8-hour day (called a 8-Hour TWA). With noise, OSHA's permissible exposure limit (PEL) is an average of 90 decibels (dBA) for all workers for an 8-hour day.
The OSHA standard uses a 5 dBA exchange rate. This means that when the noise level is increased by 5 dBA, the amount of time a person can be exposed to a certain noise level to receive the same dose is cut in half.
OSHA's requirement to protect all workers in general industry calls for employers to implement a Hearing Conservation Program where workers are exposed to a time weighted average noise level (called the "action level") of 8-Hour TWA of 85 dBA or higher.
Hearing Conservation Programs require employers to measure noise levels, provide free annual hearing exams, free hearing protection, and training.
Noise controls are the first line of defense against excessive noise exposure. The use of these controls should aim to reduce the hazardous exposure to the point where the risk to hearing is eliminated or minimized. With the reduction of even a few decibels, the hazard to hearing is reduced, communication is improved, and noise-related annoyance is reduced. There are several ways to control and reduce worker exposure to noise in a workplace.
Engineering Controls: Engineering controls involve modifying or replacing equipment, or making related physical changes at the noise source or along the transmission path to reduce the noise level at the worker's ear. Examples of inexpensive, effective engineering controls include some of the following:
Administrative Controls: These are changes in the workplace that reduce or eliminate worker exposure to noise. Examples include:
Hearing protection devices (HPDs): Hearing personal protection equipment (PPE) such as earmuffs and plugs, are considered an acceptable but less desirable option to control exposures to noise. HPDs are generally used during the time necessary to implement engineering or administrative controls, when such controls are not feasible, or when worker's hearing tests indicate significant hearing damage.
As a general rule, office temperature and humidity are matters of human comfort. OSHA has no regulations specifically addressing temperature and humidity in an office setting. However, OSHA recommends removing air contaminants and/or controlling room temperature and humidity. OSHA recommends temperature control in the range of 68-76 degrees Fahrenheit and humidity control in the range of 20%-60%.
Operations involving high air temperatures, radiant heat sources, high humidity, direct physical contact with hot objects, or strenuous physical activities have a high potential for inducing heat stress in employees. These workplaces include: iron and steel foundries, brick-firing and ceramic plants, glass products facilities, electrical utilities (particularly boiler rooms), bakeries, commercial kitchens, laundries, food canneries, chemical plants, mining sites, and smelters.
Outdoor operations conducted in hot weather, such as construction, refining, asbestos removal, and hazardous waste site activities, especially those that require workers to wear semipermeable or impermeable protective clothing, are also likely to cause heat stress among exposed workers.
There are five primary engineering and administrative control methods to control exposure to excessive heat in the workplace:
Heat reduction can also be achieved by using power assists and tools that reduce the physical demands placed on a worker.
Inadequate or poor-quality lighting systems can lead to slips, trips, and falls, shocks and burns, and inability to quickly exit a space.
Temporary lights should have guards or be recessed to prevent accidental contact with the bulb. They should be equipped with heavy duty electric cords, not be suspended by electric cords, and they should be equipped with overcurrent protection such as fuses or circuit breakers. In dark areas without temporary lighting available, provide flashlights or light sticks. Make sure workers do not enter dark spaces without suitable portable light.
The science of ergonomics studies and evaluates a full range of tasks and how they impact the health of the worker. Tasks evaluated include lifting, lowering, pushing, pulling, holding, and twisting. Back injuries are more likely to occur when an employee does any of these tasks while twisting.
Many ergonomic problems result from technological changes such as increased assembly line speeds, adding specialized tasks, and increased repetition; some problems arise from poorly designed job tasks. Any of these conditions can cause ergonomic hazards such as excessive vibration and noise, eye strain, repetitive motion, 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 as in jobs involving 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.
Repetitiveness is influenced by machine or line pacing, piece work, and unrealistic deadlines. For instance, an experienced worker packing apples (piece work) may complete many more similar exertions or movements than a new worker. Unfortunately, he or she may be performing at such a rapid rate that they may injure themselves over time. However, repetition alone is not an accurate predictor of injury. Other factors like force, posture, duration, and recovery time must also be considered.
Various kinds of tools may cause vibration that could lead to "white finger" or hand-arm vibration syndrome (HAVS). This is especially dangerous when proper damping techniques are not applied, if machines are not maintained, if tools are not alternated, or if a worker uses a vibrating tool for consecutive hours during a workday. Workers need to be trained on the hazards of working with vibrating tools, and should always allow the tool or machine to do the work.
Controls to help reduce vibration hazards include vibration isolators or damping techniques on equipment, isolating machine vibrations from the work surface, and use of dampening material. Also, make sure rotating shafts are balanced, restrict the duration of exposure, and train workers on the hazards of vibrating parts.
Ergonomic hazards are avoided primarily by the effective design of a job or jobsite and better designed tools or equipment that meet workers' needs in terms of physical environment and job tasks. Through thorough worksite analyses, employers can set up procedures to correct or control ergonomic hazards by:
Overall, industrial hygienists point out that the benefits of a well-designed, ergonomic work environment can include increased efficiency, fewer accidents, lower operating costs, and more effective use of personnel.
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