This document discusses hazards and risks associated with biological and chemical substances. It defines a hazard as a potential source of harm and risk as the likelihood of being harmed if exposed to a hazard. Biological hazards include microorganisms, viruses, toxins and other substances that threaten human or animal health. Exposure to biological hazards is common in healthcare, laboratories, agriculture and other industries. Chemical hazards can include explosives, flammables, oxidizers, poisons and have physical and health risks depending on their properties and how they are used. Proper precautions and personal protective equipment should be taken when working with biological or chemical hazards.

1. Hazard and Risk

2. SYMBOL

3. • A Hazard is a potential source of harm or
adverse health effect on a person or persons’.
• risk is the likelihood that a person may be
harmed or suffers adverse health effects if
exposed to a hazard.’

4. Biological hazards, also known as
biohazards,
• Biological substances that pose a threat to the
health of living organisms, primarily that of
humans. This can include medical waste or
samples of a microorganism, virus or toxin
(from a biological source) that can affect
human health. It can also include substances
harmful to other animals.

5. • Biological hazards, also known as biohazards, are
organic substances that pose a threat to the health
of humans and other living organisms. Generally
speaking, biological hazards include pathogenic
micro-organisms, viruses, toxins (from biological
sources), spores, fungi and bioactive substances.
Biological hazards can also be considered to
include biological vectors or transmitters of
disease. Outside the health arena, biological
hazards include substances that cause social and
economic disruption, property damage and
environmental degradation, such as insect plagues
or infestations. Worldwide, It is estimated that
around 320 000 Workers die each year from
communicable diseases caused by work-related
exposures to biological hazards (Driscoll et al.
2005; OSHA 2007).

6. • Biological hazards pose risks for many
workers in a wide variety of ways. For
example, workers in health care professions
are exposed to biological hazards via
contact with human bodily matter, such as
blood, tissues, saliva, mucous, urine and
faeces, because these substances have a
high risk of containing viral or bacterial
diseases

7. • people who work with live animals or animal
products (blood, tissue, milk, eggs) are exposed
to animal diseases and infections.
• Zoonoses have the potential to infect humans
(e.g. Q-fever, avian flu or Hendra virus) or cause
serious allergy via sensitisation.
• Exposure to biological hazards, are in contact
with laboratory cell cultures, soil, clay and plant
materials, organic dusts, food, and rubbish,
wastewater and sewerage.

8. • Exposure to moulds and yeasts is common in
some industrial processes, in workplaces with
air conditioning systems and high humidity,
and in the Construction industry.
• Exposure to biological hazards is therefore
widespread and the risk of exposure is not
always obvious.

9. Exposure to biological hazards
• human bodily matter (blood, tissues,
vomit, urine, faeces, saliva and breast
milk etc.) -75% of exposed workers
• animal products (meat, offal, skins,
bones, blood, milk and eggs) - 18% of
exposed workers

10. • live animals (mammals, birds, fish,
invertebrates and their urine or faeces) -
12% of exposed workers
• biohazard waste, sewerage and rubbish -
3.4% of exposed workers, and
• laboratory cultures - 2.8% of exposed
workers.

11. Bio hazardous agents are classified for
transportation by UN number
1. Category A, UN 2814- Infectious substances affecting
humans and animals: An infectious substance in a form
capable of causing permanent disability or life-
threatening or fatal disease in otherwise healthy
humans or animals when exposure to it occurs.
2. Category B, UN 2900- Infectious substances affecting
animals only: An infectious substance that is not in a
form generally capable of causing permanent disability
of life-threatening or fatal disease in otherwise healthy
humans and animals when exposure to themselves
occurs.

12. 3. Category C, UN 3373- Biological substance
transported for diagnostic or investigative
purposes.
4. Regulated Medical Waste, UN 3291- Waste or
reusable material derived from medical
treatment of an animal or human, or from
biomedical research, which includes the
production and testing of biological products

13. Levels of biohazard
• The United States Centers for Disease Control
and Prevention (CDC) categorizes various
diseases in levels of biohazard, Level 1 being
minimum risk and Level 4 being extreme risk.
Laboratories and other facilities are
categorized as BSL (Biosafety Level) 1-4 or as
P1 through P4 for short (Pathogen or
Protection Level).

14. • Biohazard Level 1: Bacteria and viruses including Bacillus
subtilis, canine hepatitis, Escherichia coli, varicella (chicken
pox), as well as some cell cultures and non-infectious
bacteria. At this level precautions against the biohazardous
materials in question are minimal, most likely involving gloves
and some sort of facial protection.
• Biohazard Level 2: Bacteria and viruses that cause only mild
disease to humans, or are difficult to contract via aerosol in a
lab setting, such as hepatitis A, B, and C, influenza A, Lyme
disease, salmonella, mumps, measles, scrapie, dengue fever.
"Routine diagnostic work with clinical specimens can be done
safely at Biosafety Level 2, using Biosafety Level 2 practices
and procedures. Research work (including co-cultivation, virus
replication studies, or manipulations involving concentrated
virus) can be done in a BSL-2 (P2) facility, using BSL-3
practices and procedures.

15. • Biohazard Level 3: Bacteria and viruses that can
cause severe to fatal disease in humans, but for
which vaccines or other treatments exist, such as
anthrax, West Nile virus, Venezuelan equine
encephalitis, SARS virus, tuberculosis, typhus, Rift
Valley fever, HIV, Rocky Mountain spotted fever,
yellow fever, and malaria. Among parasites
Plasmodium falciparum, which causes Malaria, and
Trypanosomacruzi, which causes trypanosomiasis,
also come under this level.

16. • Biohazard Level 4: Viruses and bacteria that cause severe
to fatal disease in humans, and for which vaccines or other
treatments are not available, such as Bolivian and
Argentine hemorrhagic fevers, Marburg virus, Ebola virus,
hantaviruses, Lassa fever virus, Crimean–Congo
hemorrhagic fever, and other hemorrhagic diseases. Variola
virus (smallpox) is an agent that is worked with at BSL-4
despite the existence of a vaccine. When dealing with
biological hazards at this level the use of a positive pressure
personnel suit, with a segregated air supply, is mandatory.
The entrance and exit of a Level Four biolab will contain
multiple showers, a vacuum room, an ultraviolet light
room, autonomous detection system, and other safety
precautions designed to destroy all traces of the biohazard.
Multiple airlocks are employed and are electronically
secured to preventboth doors opening at the same time. All
air and water service going to and coming from a Biosafety
Level 4 (P4) lab will undergo similar decontamination
procedures to eliminate the possibility of an accidental
release.

17. Chemical hazards

18. • Chemicals : physical and health hazards.
• Chemicals can exhibit more than one
hazard or combinations of several
hazards.
• Several factors can influence how a
chemical will behave and the hazards the
chemical presents, including the severity
of the response:

19. • Concentration of the chemical.
• Physical state of the chemical (solid, liquid, gas).
• Physical processes involved in using the chemical
(cutting, grinding, heating, cooling, etc.).
• Chemical processes involved in using the
chemical (mixing with other chemicals,
purification, distillation, etc.).
• Other processes (improper storage, addition of
moisture, storage in sunlight, refrigeration, etc.).

20. • It is important to note that the following
sections are general guidelines. Laboratory
personnel should always review MSDSs and
other resources FIRST, before working with
any chemical.
• MSDS : Material Safety Data Sheets

21. A. Explosives
• Whenever work using potentially explosive
compounds:
1. Always use the smallest quantity of the
chemical possible.
2. Always conduct the experiment within a fume
hood and use in conjunction with a properly
rated safety shield.

22. 3. Be sure to remove any unnecessary
equipment and other chemicals
(particularly highly toxic and flammables)
away from the immediate work area.
4. Be sure to notify other people in the
laboratory what experiment is being
conducted, what the potential hazards are,
and when the experiment will be run

23. 5. Do not use metal or wooden devices
when stirring, cutting, scraping, etc. with
potentially explosive compounds. Non-
sparking plastic devices should be used
instead.
6. Ensure other safety devices such as high
temperature controls, water overflow
devices, etc., are used in combination to
help minimize any potential incidents.

24. 7. Properly dispose of any hazardous waste
and note on the hazardous waste tag any
special precautions that may need to be
taken if the chemical is potentially explosive.
8. Always wear appropriate PPE, including
the correct gloves, lab coat or apron, safety
goggles used in conjunction with a face
shield, and explosion-proof shields when
working with potentially explosive chemicals.

25. 9. For storage purposes, always date chemical
containers when received and opened.
10. Compounds that must remain moist or wet so
they do not become explosive (ex. Picric acid, 2,4-
Dinitrophenyl hydrazine, etc.).
11. Attention to any potentially explosive compounds
that appear to exhibit the following signs of
contamination:
– Deterioration of the outside of the container.
– Crystalline growth in or outside the container.
– Discoloration of the chemical.

26. B. Flammable and Combustible Liquids
Classification Flash Point Boiling Point
Flammable Liquid
Class IA <73 degrees F <100 degrees F
Class IB <73 degrees F >=100 degrees F
Class IC >=73 degrees F, <100 degrees F >100 degrees F
Combustible Liquid
Class II >=100 degrees F, <140 degrees F --
Class IIIA >=140 degrees F, < 200 degrees F --
Class IIIB >=200 degrees F --

27. C. Oxidizers and organic peroxides
• Concern for laboratory safety due to their
ability to promote and enhance the potential
for fires in labs.
• fire tetrahedron :
• A fuel source.
• An oxygen source.
• An ignition source
• A chemical reaction.

28. D. Poisons
• A chemical that has a median lethal dose
(LD50) of more than 50 milligrams per
kilogram, but not more than 500 milligrams
per kilogram of body weight when
administered orally to albino rats weighing
between 200 and 300 grams each.

29. • A chemical that has a median lethal dose
(LD50) of more than 200 milligrams per
kilogram, but not more than 1000 milligrams
per kilogram of body weight when
administered by continuous contact for 24
hours (or less if death occurs within 24 hours)
with the bare skin of albino rabbits weighing
between two and three kilograms each.

30. • A chemical that has a median lethal
concentration (LC50) in air of more than 200
parts per million, but not more than 2000
parts per million by volume of gas or vapor, or
more than two milligrams per liter but not
more than 20 milligrams per liter of mist,
fume, dust, when administered by continuous
inhalation for one hour (or less if death occurs
with in one hour) to albino rats weighing
between 200 and 300 grams each.

31. Some questions to ask before working with
poisonous chemicals:
1. Do I need to use the poisonous chemical or
can a less toxic chemical be substituted?
2. What are the routes of entry into the body for
the poison (inhalation, ingestion, injection, or
skin absorption)?
3. What are the signs and symptoms of potential
chemical exposure?

32. 4. What are the proper PPE required (type
of glove, safety glasses vs. splash goggles,
face shield, etc.)?
5. Does the chemical require any special
antidote?
6. What are the emergency procedures to
be followed?