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Course 750 - Introduction to Industrial Hygiene

Safety guides and audits to make your job as a safety professional easier

Biological Hazards


Viruses, bacteria, and fungi can be biohazards.

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.

1. Biological hazards include _____ that can cause acute and chronic infections.

a. formaldehyde, radon, and pesticides
b. carbon dioxide, nitrogen oxides, and ozone
c. bacteria, viruses, fungi, and other living organisms
d. exposure to any contaminant

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Biological Agents

Testing for botulism toxins.

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.

2. _____ is an acute infectious disease caused by a spore-forming bacterium called Bacillus anthracis.

a. Anthrax
b. Bloodborne pathogens
c. Avian flu
d. Botulism

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Biological Agents (Continued)

Sampling for biological hazards.

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.

3. Which of the following is one of the most easily produced plant toxins and has been used as a bioterrorist weapon?

a. Mold
b. Botulism
c. Ricin
d. Hantavirus

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Biological Agents (Continued)

3-D image of a COVID-19 virus.

Coronavirus. Mild illnesses in humans include some cases of the common cold (which is also caused by other viruses, predominantly rhinoviruses), while more lethal varieties can cause SARS, MERS, and COVID-19.

  • SARS-CoV, the virus that caused severe acute respiratory syndrome (SARS), which was first identified in 2003
  • MERS-CoV, the virus that caused Middle East respiratory syndrome (MERS), which was first identified in 2012
  • SARS-CoV-2, the second strain of the coronavirus that causes COVID-19, which was first identified in 2019

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 CDC as the most likely to be used as biological weapons. Many VHFs can cause severe, life-threatening disease with high fatality rates.

4. Which of the following diseases is unique to humans?

a. Severe Acute Respiratory Syndrome (SARS)
b. Small Pox
c. Tularemia
d. Viral Hemorrhagic Fevers (VHFs)

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Risk of Exposure to Biological Agents

Sampling food for biological agents.

Various industries present unique biological hazards during the normal course of work. There are over 190 important biological agents that may be infectious, allergenic, toxic, or carcinogenic in the workplace. Many occupational groups are exposed to these biohazards, but risk may be greatest among:

  • health care and laboratory workers, and
  • agricultural, forestry, and fishing industry workers.

We have listed industries below that typically experience exposure to biohazards. Click on each bolded industry title below to see the types of hazards within each industry and the recommended preventive measures.

. The food industry includes cheese, yoghurt, salami or food additive production, and bakeries.

There is a risk of exposure to:

  • Molds/yeasts, bacteria and mites cause allergies.
  • Organic dusts of grain, milk powder or flour contaminated with biological agents.
  • Toxins such as botulinustoxins or aflatoxins

Preventive measures include:

  • Closed processes
  • Avoid aerosol formation
  • Separate contaminated work areas
  • Appropriate hygiene measures


There is a risk of exposure to:

  • Several viral and bacterial infections such as HIV, hepatitis, or tuberculosis.
  • Needlestick injuries

Preventive measures include:

  • Safe handling of infectious specimens, sharps waste, contaminated linen and other material.
  • Safe handling and cleaning of blood spills and other body fluids.
  • Adequate protective equipment, gloves, clothing, glasses.
  • Appropriate hygienic measures


There is a risk of exposure to:

  • Infections and allergies when handling microorganisms and cell cultures (human tissues).
  • Accidental spills and needlestick injuries.

Preventive measures include:

  • Microbiological safety cabinets
  • Dust and aerosol-reducing measures
  • Safe handling and transport of samples
  • Appropriate personal protection and hygiene measures
  • Decontamination and emergency measures for spills
  • Restricted access
  • Biosafety labels

. Agriculture includes forestry, horticulture, and animal and fodder production

There is a risk of exposure to:

  • Bacteria, fungi, mites, and viruses transmitted from animals, parasites and ticks.
  • Respiratory problems due to microorganisms and mites in organic dusts of grain, mild powder, flour, or spices.
  • Specific allergic diseases like farmer's lung and bird breeder's lung.

Preventive measures include:

  • Dust and aerosol-reducing measures
  • Avoid contact with contaminated animal or equipment
  • Protection against animal bites and stings
  • Preservatives for fodder
  • Cleaning and maintenance


There is a risk of exposure to:

  • Skin problems due to bacteria.
  • Bronchial asthma due to molds/yeasts in circulating fluids in industrial processes such as grinding, pulp factories', and metal and stone cutting fluids.

Preventive measures include:

  • Local exhaust ventilation
  • Regular maintenance, filtering, and decontamination of fluids and machinery.
  • Skin protection
  • Appropriate hygiene measures.

. These industries typically require working in air-conditioned environments and high humidity.

There is a risk of exposure to:

  • Allergies and respiratory disorders due to molds/yeasts.
  • Legionnaires disease

Preventive measures include:

  • Dust- and aerosol-reducing measures.
  • Regular maintenance of ventilation, machinery, and work areas.
  • Restrict number of workers. Maintaining high hot (tap) water temperatures.


There is a risk of exposure to:

Molds/yeasts and bacteria cause allergies and respiratory disorders.

Preventive measures include:

  • Dust- and aerosol-reduction
  • Decontamination
  • Adequate personal protective equipment

. This category includes processing natural materials like clay, straw, reed; redevelopment of buildings.

There is a risk of exposure to:

Molds and bacteria due to deterioration of building materials.

Preventive measures include:

  • Dust- and aerosol-reducing measures
  • Appropriate personal protection and hygiene measures

5. The risk of exposure to biohazards may be greatest in the _____.

a. metal and wood processing industries
b. food industry
c. construction industry
d. healthcare and agriculture industries

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