CHEMICAL HAZARDS

MARK ANTHONY B. ENOY BS EE-III mark_enoy@yahoo.com
CHEMICAL HAZARDS
INTRODUCTION
What is the definition of chemical hazard?
 A chemical hazard is any substance that can cause harm, primarily to people. Chemicals of all
kinds are stored in our homes and can result in serious injuries if not properly handled.
 any hazard that results from the accidental, deliberate or potential release of a noxious
substance into the environment.
 An element or mixture of elements or synthetic substances that are considered harmful to
people.
 A chemical hazard arises from contamination of an area with harmful or potentially harmful
chemicals. Possible sources of chemical hazards include:
- the burning of fossils, materials and chemicals used in construction and industry, pollution
of the environment and water supply, chemical spillages, industrial accidents, and the
deliberate release of toxic materials.
- Household cleaning products such as bleach, paints, acids, solvents especially chemicals in
an unlabelled container (warning sign!), it can result in harmful chlorine gas or hydrochloric
acid if carelessly used.
- gases like acetylene, propane, carbon monoxide, helium and Gasoline fumes from
containers for lawnmowers or boats can result in major health hazards if inhaled.
How Chemicals Enter the Body
 Four Routes of Entry:
1. Ingestion – swallowing the chemical
- chemicals may be swallowed
accidentally if food or
cigarettes (or hands) are
contaminated. For this
reason student and workers
should not drink, eat, or
smoke in areas where they
may be exposed to toxic
chemicals.
2. Inhalation – breathing in the chemical
- Chemicals in the air are breathed in
through the mouth or nose.
- Gases & vapors are absorbed
through the lungs directly into the
bloodstream.
- The size of dust particles or mist
droplets can affect where the
chemical settles in the respiratory
tract.
3. Absorption – the chemical soaks
through the skin
-Some chemicals can pass through the
skin into the body.
4. Injection- it can occur when a sharp
object (needle) punctures the skin and
injects a chemical (or virus) directly into
the bloodstream.

Chemicals have symbols to show their possible hazards. Chemicals are grouped according to the
types of effects they could have.
- Hazard symbols are recognizable symbols designed to warn about hazardous materials or locations. The use of
hazard symbols is often regulated by law and directed by standards organizations. Hazard symbols may appear
with different colors, backgrounds, borders and supplemental information in order to signify the type of hazard.
Effects of Chemical Hazards
Some of the health effects of exposure to hazardous chemicals include:
 skin irritation
 occupational asthma
 systemic chemical poisoning
 chemical burns from corrosives
 cancer.
- About 47 000 persons die every year as a result of such poisoning. Many of these poisonings occur in
children and adolescents, are unintentional (“accidental”), and can be
prevented if chemicals were appropriately stored and handled. Chronic, low-level exposure to various
chemicals may result in a number of adverse outcomes, including damage to the nervous and immune
systems, impairment of reproductive function and development, cancer, and organ-specific damage.
source: World Health WHO
- Hundreds of millions of people in the developing world are regularly exposed to potentially
harmful indoor emissions, which are believed to contribute to chronic lung disease, cancer,
and ARI.
source: World Resources Institute
Corrosive Chemical cause burns if it comes into contact with
the skin
Highly flammable Can easily catch fire
Toxic Could cause harm if the chemical comes into
contact with skin, if ingested or if vapors are
breathed in.
Harmful to the
environment
Will cause harm to living organisms if released into
the environment.
Irritant Damages skin or eyes if they come into contact
with the chemical.
Explosive Chemical could cause an explosion.
Carcinogen
Carcinogen Chemical can cause cancer if it comes into contact
with the body or is ingested.
Radiation Material is radioactive and gives off ionizing
radiation

How do you get information about hazardous chemicals?
- You can get information two ways:
1. from the product label,
2. from the product material safety data sheet.
- Material safety data sheets or “MSDSs” are information sheets on products
that:
• tells what chemicals are in the product,
• what the hazards of the chemicals are,
• how to protect yourself from the hazards.
Protecting yourself from hazardous chemicals
- Know what is in the product your work
with (read the “MSDSs”)
- Use the smallest amount of a chemical
to do the job
- Maintain machinery and
equipment to prevent
leaks or releases
- Using available ventilation
to reduce amounts of
chemicals in the air,
- Keeping lids, doors or covers closed on
chemical processes
- Wearing necessary personal protective
equipment.
IF YOU HAVE BEEN EXPOSED TO A CHEMICAL AND FEEL SICK:
- Let your instructor or supervisor know
- Find out what the chemical was
- Follow the first aid directions in the MSDS
- Get medical attention as needed
- Check your (PPE) Personal Protective equipment before going back to the area.
IN THE CASE OF A LEAK OR SPILL, PROTECT YOURSELF BY:
- Informing your instructor or supervisor of unusual odors, spills, or releases
By leaving an area of a large spill or chemical release

Food Safety - Chemical Hazards
- The accidental or intentional addition of excessive amounts of toxic chemicals to food can cause
illness or even death. No poisonous or toxic materials should be used that are not immediately
necessary or appropriate for the maintenance of the establishment, the cleaning or sanitizing of
equipment or utensils, or the control of insects or rodents. Chemicals must be used in accordance with
manufacturers' recommended instructions. No poisonous or toxic materials should be used in a way
that contaminates food.
Chemical Contamination in Food
- The contamination of food by chemical hazards is a worldwide public health concern and is a leading
cause of trade problems internationally. Contamination may occur through environmental pollution of
the air, water and soil, such as the case with toxic metals, PCBs and dioxins, or through the
intentional use of chemical compounds that may contaminate incoming food products like herbicides,
pesticides, growth-limiting chemicals (such as sprout retardant on potatoes), and fertilizers. The
critical control procedure is to immediately wash all incoming produce to remove these chemicals and
to dilute these chemicals to a safe level.
Cleaning Compounds
- In-house cleaning supplies and pesticides are chemical hazards. Detergents, sanitizers, polishes,
caustics, acids, and other cleaning supplies must be stored in an area, cupboard, or room that is
separate from any food supplies. Detergents, bleaches, etc., should never be stored in a food container
nor measured in a food container. These products should always be labeled prominently and
distinctly, clearly indicating the contents. Detergents, sanitizers, or related compounds should not be
stored above sinks used for food preparation.
Culinary Chemicals
- All chemicals used in food should be weighed or very carefully measured before being added to food
products. People have become very ill when too much MSG (monosodium glutamate), nitrates, and
sulfates have been added to food.
Chemical food poisoning results from eating a plant or animal that contains a toxin.
 The poisoning occurs after ingesting poisonous species of
mushrooms or plants or contaminated fish or shellfish.
 The most common symptoms are diarrhea, nausea, and
vomiting and sometimes seizures and paralysis.
 The diagnosis is based on symptoms and examination of the
ingested substance.
 Avoiding wild or unfamiliar mushrooms and plants and
contaminated fish reduces the risk of poisoning.
 Replacing fluids and ridding the stomach of the toxic substance are the best forms of treatment;
however, some substances are deadly.
Pest Control and Materials Used
- The key to pest control is cleanliness, not chemicals. The interior and exterior of the building
should be maintained according to the cleaning schedule and doors must fit tightly. Open poison
bait stations should not be used. Instead, trap rodents and insects so that the bodies can be
disposed of properly. Vapona strips and automatic intermittent aerosol insecticide dispenser
should not be used in foodservice facilities.

Chemical Hazards in Laboratory
o Hazards of Chemicals
Chemicals in the organic lab can be flammable, volatile, health hazardous, and/or corrosive. Individuals
who work in a laboratory are required to be adequately informed about the physical and health hazards
present in the laboratory, the known risks, an what to do if an accident occurs. Every laboratory worker
must be trained to know the location and proper use of available personal protective clothing and
equipment. The laboratory supervisor is responsible for providing information about any hazards present
in the lab. This information must be provided at the time initial assignment and prior to any assignments
involving new potential chemical exposure situations.
o Safety Precautions :
- Chemical and Thermal Burns. Many inorganic chemicals such as the mineral acids and alkalis
are corrosive to the skin and eyes. Likewise, many organic chemicals, such as acid halides,
phenols, and so forth are corrosive and often toxic. If these are spilled on the desk, in the hood, or
on a shelf, call for assistance in cleaning them up.
- Absorption of Chemicals. Keep chemicals off the skin. Many organic substances are not
corrosive, do not burn the skin, or seem to have any serious effects. They are, however, absorbed
through the skin, sometimes with dire consequences. Others will give a serious allergic reaction
upon repeated exposure, as evidenced by severe dermatitis. Be careful about touching your face
or eyes in the lab; make sure your hands are clean first. Gloves will be available in the lab.
However, gloves provide only a temporary layer of protection against chemicals on your skin and
may be permeable to some chemical reagents, without visible deterioration. If your gloves come
in contact with a chemical reagent, remove them, wash your hands, and get a new pair
immediately.
- Inhalation of Chemicals. Keep your nose away from chemicals. Many of the common solvents
are extremely toxic if inhaled in any quantity or over a period of time. Do not evaporate excess
solvents in the laboratory; use the hood or a suitable distillation apparatus with a condenser. Some
compounds, such as acetyl chloride, will severely irritate membranes in your eyes, nose, throat,
and lungs, while others, such as benzyl chloride, are severe lachrymators, i.e. they induce eye
irritation and tears. When in doubt, use the hood or consult with the laboratory instructor about
the use of chemicals required for your work. Specific safety information about chemicals used is
included in each experiment write up. MSDS (Material Safety Data Sheets) are available on the
DCIS file server and summarize safety information about substances used in the lab.
- Ingestion of Chemicals. The common ways of accidentally ingesting harmful chemicals are: (1)
by pipet, (2) from dirty hands, (3) contaminated food or drink and (4) food use of chemicals taken
from the laboratory. Below are ways to avoid accidental ingestion of chemical reagents.
• Pipets must be fitted with suction bulbs to transfer chemicals. DO NOT USE MOUTH
SUCTION.
• Wash your hands before handling anything (cigarettes, chewing gum, food) which goes into
your mouth. Wash your hands when you leave the laboratory.
• Do not eat or drink in the laboratory. Use the water fountains for a drink--not a laboratory
faucet. Remove gloves and wash your hands before using the water fountain or bathroom.
• Never use chemicals (salt, sugar, alcohol, bicarbonate, etc.) from the laboratory or stockroom on
food. The source containers may be contaminated or mislabeled.
• Never use laboratory glassware as a food or drink container.
• Never store food or drink in a laboratory refrigerator or ice machine. Never consume ice from a
laboratory ice machine.

Laboratory Safety Guidelines
1. Be familiar with your departmental safety committee and its members.
2. Discuss your safety concerns with your supervisor or seek advice from the safety committee which meets regularly to discuss
problems and seek solutions.
3. Report all accidents or near misses to your supervisor and complete the UNB Accident Report Form.
4. Encourage students and fellow staff members to develop a concern for their own safety and that of others.
5. Evaluate work for specific hazards and for minimizing the risk of injury.
6. Provide incentive to students and staff for safety performance.
7. Read the appropriate safety manuals. Students must be familiar with the laboratory's safety rules, staff with the UNB Safety
Handbook, users of radioactive materials with the UNB Radiation Safety Manual.
8. Conduct periodic laboratory inspections to identify and correct hazardous conditions and unsafe practices.
9. Take opportunity to discuss the results of inspections and aspects of laboratory safety with staff and students.
10. Make learning how to be safe an integral and important part of the science education process.
11. Include in every pre-lab discussion consider-ations for environmental health and safety.
12. Do not work alone in any laboratory without prior knowledge of your supervisor or advising the Security Department.
13. Do not run experiments unattended unless they are fail-safe.
14. When conducting experiments with hazards or potential hazards, ask yourself these questions:
. "What are the hazards?"
. "What are the worst possible things that could go wrong?"
. "How will I deal with them?"
. "What are the prudent practices, protective facilities and equipment necessary to minimize the risk of exposure to the hazards?"
15. Review accidents in-house to avoid re-occurrence.
16. Store only minimum amounts of flammable liquids in each laboratory. Maximize container size 5 L.; maximum volume 50 L.
17. Do not pipette by mouth.
18. Do not smoke, eat, or drink in the laboratory.
19. Do not store food in chemical refrigerators.
20. Be familiar with procedures for such dangers as fire, explosion, poisoning, chemical spill, vapor release or personal
contamination.
21. Read the 'IN CASE OF FIRE' poster next to every pull station and posted prominently on bulletin boards in departments.
22. Store acids and bases separately. Store fuels and oxidizers separately.
23. Maintain a chemical inventory to avoid purchasing unnecessary quantities of chemicals.
24. Use warning signs to designate particular hazards.
25. Maintain good housekeeping practices in all working areas.
26. Develop specific work practices for individual experiments, such as those that should be conducted only in a fume hood or
involve especially hazardous chemicals.
27. Acquire appropriate safety equipment (spills, PPE, fire).
28. Use safety glasses and lab coats in all laboratories.
29. Use appropriate personal protective equipment - goggles, face shields, gloves, lab coats, and bench top shields. Many
hazardous experiments should be done in a fume hood.
30. Be familiar with the location of fire extinguishers, safety showers, eye-wash facilities and fume hoods in each laboratory.
31. Access safety resources (department safety library, main library, Internet or supervisor).
32. Provide guards on all vacuum pumps and secure all compressed gas cylinders.
33. Be familiar with the location of the nearest First Aid kit and the F.A. trained staff in your area.
34. Ensure MSDS are readily available for all chemicals in use.
35. Require ground plugs on all electrical equipment. Ensure electrical cords are not damaged.
36. Label all chemicals to show nature and degree of hazard (WHMIS, TDG).
37. Date chemicals when purchased and discard after predetermined maximum periods of storage.
38. Follow procedures for the safe and environmentally acceptable disposal of lab wastes (paper, glass, sharps, chemical,
radioactive, biological).
39. Store flammable chemicals in fire-rated facilities. Most departments have fire-rated central storage rooms and/or flammable
storage cabinets in labs, where required.
40. Store odoriferous chemicals in a well ventilated area but do not clutter fume hood with chemicals.

Chemical Hazards in Mining
Chemical hazards exist where exposure to an element or compound could cause negative health effects.
Examples of common chemical hazards to workers involved in mining processes include silica dust,
solvents and asbestos.
Chemicals in the mining industry pose a range of hazards to exposed miners, from mild health effects to
death. Some chemicals cause or contribute to chronic health problems, such as heart or kidney disease or
cancer. Others cause acute injuries or illnesses such as dermatitis, burns, and poisonings. Some chemicals
pose hazards by contributing to fires and explosions. The toll of chemically-related injuries and illnesses
in the mining industry can be obscured by years of latency between an exposure to a chemical and the
onset of an illness.
CONTROL METHODS FOR CHEMICAL HAZARDS
A. Designated Area
- This is an area assigned for the usage of
either a particularly hazardous substance
or purpose. For example, if carcinogens are
being used in the lab, a "designated
area" should be assigned, and warning label
should be posted.
1. Clean Area
There are no longer clean areas allowed in an
active research laboratory.
B. Engineering Controls
This is the most effective and desirable method
for minimizing risk of exposure
either to toxic chemicals or to mechanical
equipment. Examples of engineering
controls: guards, remote controls, or interlock
systems.
However, for toxic fumes, mists, and vapors,
ventilation systems are the best
approaches to help reduce personal exposure
to acceptable levels. Generally, there
are two types of ventilation systems:
1. Dilution Ventilation
In most buildings a certain percentage of the
building air is recirculated
periodically through the building ventilation
systems but in laboratories all air
is exhausted directly to the outside. This “single
pass” system is a type of
“dilution ventilation” system for controlling low
risk airborne contaminants.
They are simply exhausted to the outside
before they can build to hazardous
levels.
2. Local Exhaust Ventilation
Used for moderate to high-risk contaminants.
Local exhaust systems capture
the airborne contaminants much more
effectively than dilution systems such
as chemical fume hoods.
3. Fume Hoods
The fume hood is designed to contain and
disperse gases, vapors, and aerosols
to the external environment. It does not
provide absolute containment or
protection from the materials in the hoods,
however, a properly designed hood
in a properly designed room can provide
adequate protection of the following
practices are observed:
• Inspect and ensure that the hood is working.
• Do not store chemicals and equipment in the
hood
• Remove unnecessary chemicals and
equipment.
• All equipment and experiments should be at
least 6 inches back from the
front sash.
• Position the sash no higher than the approved
working height that is
designated by a fluorescent yellow sticker.
• When evaporating or distilling perchloric acid,
special perchloric acid
fume hoods MUST be used.

C. Work Practice Controls
In most cases, a well-designed set of work
practices is the best risk management
tool.
1. Chemical Transportation
Assure that an unbreakable secondary
container is being used, and that
transport carts are designed for this purpose.
2. Eating, Drinking and Smoking
There should be no eating, drinking, smoking,
chewing of gum or tobacco, application of
cosmetics, storage of utensils, food, or food
containers in the laboratories.
3. Pipetting
Mechanical pipetting aids should always be
used for all pipetting procedures.
Oral pipetting is prohibited.
4. Personal Hygiene
All personnel should wash their hands
immediately after the completion of
any procedure in which chemicals have been
used and when they leave the
laboratory. If hazardous chemical exposures
occur to skin, immediately
shower or wash affected areas.
5. Housekeeping
Keeping the working area clean and orderly
reduces the frequency and
severity of accidents. Here is some common
sense tips:
• Keep aisles, exits, stairs and hallways free of
obstructions.
• Avoid slip hazards by keeping the floor clean
of ice, stoppers, glass beads
or rods, other small items and spilled liquids.
• Keep drawers and cabinet doors closed.
• Never store chemicals on the floor.
• Workspaces and storage areas should be kept
clear of broken glassware,
leftover chemicals and scraps of paper.
• Place all non-contaminated broken glass in
rigid containers clearly marked
"Broken Glass".
D. Standard Operating Procedures (SOP)
Lab staff should prepare a SOP for hazardous
operations as well as the use,
storage and disposal of hazardous materials.
SOPs serve as a training tool for new
workers.
E. Personal Protective Equipment (PPE)
PPE comprises of clothing or equipment that is
used to isolate a worker from
direct exposure to workplace hazards. Examples
of PPE include the following:
• Protective clothing
• Gloves
• Eye Protection
• Respirators
• Harnesses
PPE is used in conjunction with engineering and
administrative controls for
worker protection. It should provide adequate
protection if it is properly worn and
appropriately used. Prior to usage, consult
EH&S (752-1493) to ensure proper
PPE selection.
1. Guidelines for PPE Usage
a) PPE protects differently for each hazard
It does not provide protection against all
hazards. Choose appropriate
PPE depending on the hazard and task you are
performing. Remember:
USING THE WRONG PPE MAY BE AS BAD AS
USING NO PPE!
b) PPE does not eliminate the hazard
Know the limitations of PPE. Follow SAFETY
PRECAUTIONS while
working.
c) Use and maintain PPE properly to ensure its
performance
Having safety goggles does no good if it's
resting on your head.
d) Be aware that there may be hazards with
using PPE
Talk to your supervisor or EH&S before using
PPE.
e) PPE does not protect workers the same way!
PPE should be properly sized and fitted to
ensure its adequacy.
f) Wear more than the minimum PPE!
g) Leave your uniform at work and have it
laundered there if a service is
provided. If you take your uniform home, then
wash it separately to avoid
contaminating other clothes.
h) Take off your jewelry (i.e. rings and watches).

This reduces chemical seepage and contact with
electrical sources.
2. Protective Clothing
• Lab clothing (i.e. coats and aprons) should be
worn in the laboratories in
order to keep contaminants from getting onto
street clothes.
• Open-toed shoes, sandals or shoes made of
woven material should not be
worn in the laboratory.
• Shorts, cut-offs and miniskirts are
inappropriate.
• Long hair and loose clothing should be
constrained.
• Jewelry (i.e. rings, bracelets, and watches)
should not be worn in order to
prevent chemical seepage under the jewelry,
contact with electrical
sources, catching on equipment and damage to
jewelry itself.
3. Gloves
Appropriate gloves should always be used when
working in the lab.
Disposable gloves should be discarded after
each use and immediately after
overt contact with chemical.
4. Eye Protection
Devices to provide appropriate eye protection
should be used in the laboratory
work area. The type of device used will depend
upon the hazard presented by
the operation and/or chemical in use. Splash
goggles (vented or non-vented)
are most appropriate when working with liquid
chemicals.
5. Respiratory Protection
At times, masks or respirators may be required
for some procedures where
there may be a potential for inhalation
exposure. However, respirator users
should consult EH&S to assure accordance with
the UCI Respiratory
Protection Program.
F. Chemical Hygiene Plan (CHP)
The CHP is designed to protect you from the
health hazards associated with
hazardous chemicals in your lab. The CHP
outlines standard operating procedures
for all work involving hazardous substances in
your lab. The CHP must be
available to employees in the lab at all times.
G. Chemical Storage
1. Chemical Storage
• Separate incompatible chemicals. Check the
shelf life of your chemical
inventory periodically.
• Store chemicals properly in the
cabinets or on the shelves provided.
• Do not store chemicals in fume hoods.
• Install smoke and heat detectors and
fire extinguishers.
• Do not overcrowd or overload shelves.
• Keep storage facilities locked.
• Keep aisles clutter-free and unobstructed.
2. Labeling
Since there is a wide variety of chemicals used
in the laboratories, appropriate
labeling is extremely important. In order to be
able to determine its use,
disposal and hazards, the UC Davis Hazardous
Communication Program
requires chemicals to be properly labeled.
3. Flammable Storage Cabinets
• Flammable cabinets are designed to protect
flammable liquids against
flash fire; the cabinet should ALWAYS remain
closed when not in use.
• Ensure cabinet can contain any spilled
flammable liquids to prevent fire
spread.
• Cabinet should only accommodate up to 60
gallons of flammable liquids.
• All cabinets should be UL (Underwriter's
Laboratory) Approved and
labeled "Flammable - Keep Fire Away".
4. Lab Refrigerators
• Use only an EH&S approved “lab safe”
refrigerator designed for storing
chemicals.
• NEVER store chemicals and food in the same
refrigerator.
• If not “lab safe” refrigerator, it MUST be
labeled "Caution - Unsafe For
Storage Of Flammable Solvents".
5. Special Considerations
• Store carcinogens separately.

• Store water-sensitive chemicals and
concentrated acids separately.
• Use heat-resistant cabinets for flammable
liquids.
• Wooden cabinets are acceptable for solids.
• Peroxide forming chemicals deserve special
consideration. Due to unusual
stability problems, careful records of the
storage history of compounds
that form peroxides on standing should be
maintained and periodically
reviewed. Discard peroxide forming chemicals
by the manufacturer’s
expiration date or after 6 months of opening,
whichever is sooner.
H. Chemical Waste
1. Hazardous Waste Storage
• All waste must be segregated into categories
and stored to prevent incompatible mixtures
within or among individual containers.
• Waste must be kept in leak-proof containers
with adequate secondary containment in case
of breakage or spillage.
• Waste storage area must be inspected at least
weekly.
• All waste containers must be labeled as
required by UC Davis –
Hazardous Waste Management Program.
• Documentation must be made on the
Hazardous Waste Tag each time
waste is placed in a container.
2. Disposal of Hazardous Waste
Hazardous waste, whether chemical,
radioactive or bio-hazardous.
Chemical Safety: Ten Basic Rules
1. Know the hazards of chemicals in use.
2. Label all chemicals & their waste
properly.
3. Use PPE while handling hazardous
chemicals.
4. Work with volatile & hazardous chemicals
in a fume hood.
5. Store flammables properly.
6. Do not work alone with hazardous
chemicals.
7. Maintain clear access to exits, showers &
eyewashes
8. Keep work areas free to clutter.
9. Wash promptly when chemical contacts
skin.
10. Do not eat, drink, and apply cosmetics
in lab.
Common Specific chemical issues:
Histamine
- is a protein that is stored in the mast
cells of the body that causes
inflammation, mucus productions and
smooth muscles when there is
allergen. This used in diagnostic and
treatment procedures. May cause
rashes, stomach acid.
Bisphenol A
- used to make polycarbonate polymers
and epoxy resins. Can damage in ovaries
and endometrium thickening.
Melamine
- is widely used in plastics, adhesives,
countertops, dishware, whiteboards.
Causes Irritability, blood in urine, little or no
urine, signs of kidney infection, high blood
pressure.
Acrylamide
- used in wastewater treatment, gel
electrophoresis, papermaking, ore proc
essing, and the manufacture
of permanent press fabrics. High levels
of acrylamide to cancer in animals and
neurological damage in humans,
including muscle weakness and
impaired muscle coordination.
Persistent Organic Pollutants (POPs)
- are chemical substances that persist
in the environment, bioaccumulate
through the food web, and pose a
risk of causing adverse effects to
human health and the environment.
Ex. pesticides, polychlorinated
biphenyls (PCBs), polychlorinated
naphthalenes (PCNs). May cause
organ damages or even death.

CHEMICAL HAZARDS

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to CHEMICAL HAZARDS

Similar to CHEMICAL HAZARDS (20)

More from Mark Anthony Enoy

More from Mark Anthony Enoy (12)

Recently uploaded

Recently uploaded (20)

CHEMICAL HAZARDS