After Readin this article of this lesson, you will be able to:
- Define the term toxicity and hazard.
- Define Permissible Exposure Limit of chemicals.
- Describe the physical and health hazards of chemicals.
- Elaborate the route of entry of chemicals.
- List the measures for the safe storage of chemicals. And Safe Chemical Storage procedure.
- Classify the chemical emergencies into various classes.
- Describe the importance of eye/face wash, shower point.
- Elaborate the safety measures for acid, bases and alkali metals.
The ability of a chemical substance to cause harm.
Likelihood that a material will cause harm under the conditions of use.
- Permissible Exposure Limit (PEL):
PEL is regulatory limit set by OSHA (Occupational Safety and Health Administration) on the amount or concentration of a substance in the air.
The PEL is further divided into two limits:
- UEL (upper exposure limit).
- LEL (lower exposure limit).
3. Physical Hazard:
Hazards due to physical characteristics of a chemical are known as physical hazards.
a. Flammable – catches fire easily and bums rapidly. This term is used mostly for liquid & gas fuels (with flash point lower than 37.8c).
b. Combustible – will burn under most conditions. This term is used for solid fuels, (with flash point lower than 37.8c.)
c. Explosive – will explode / detonate releasing hot gases.
d. Oxidizer – yields oxygen to enhance combustion, may cause ignition of combustibles with no external source.
e. Organic peroxide – uniquely hazardous, potentially explosive.
f. Unstable – tends to decompose during normal handling and storage.
g. Water reactive – reacts with water to release flammable gases| causes fire or presents a health hazards.
3.1 Health Hazard:
The hazards which are caused by the chemicals on the health, body and mind of the humans are known as the health hazards.
- Carcinogenic – A group of chemicals which cause cancer or suspected to cause cancer.
- Toxic Agent – A group of chemicals which are poisonous / cause acute or chronic effects.
- Reproductive toxin (teratogen) – A group of chemicals which could have harmful effect on male or female reproductive system or on developing fetus.
- Irritant – A group of chemicals which can cause inflammation of skin or eyes’
- Corrosive — A group of chemicals which cause irreversible damage to living tissue.
- Sensitizer – A group of chemicals which cause the exposed se during normal handling and person to develop allergies to the substance or a chemical.
- Target organ-specific agents – A group of chemicals which are hazardous to specific organs in body e.g. lungs, liver, blood, kidneys, nervous system etc.
Route of Entry Of Chemicals:
For a chemical to have an effect on a person, He/ she must be exposed to it and some of it must get into his/ her body to cause any health problem or hazard.
There are 5 ways of entry of chemicals into the human body which are as follows:
- Inhalation / breathing.
- Absorption through the skin.
- Ingestion / swallowing.
- Eye Contact.
- Inhalation / breathing:
Most common route, gases / vapors can pass to blood, solid particles inhaled into lungs.
- Absorption through the skin:
Many solids, liquids, vapors and gases can be absorbed through the skin.
- Ingestion / swallowing:
While not intentional, failure to wash hands, lab, etc.
Accidents handling glass, sharps, etc.
- Eye Contact:
The rout of entry of chemical dictates the selection and use of the relevant personal protective equipment for handling of chemicals.
5. Safe Chemical Storage:
There are a lot of things to consider while discussing the importance of safe chemical storage.
5.1 inventory of chemicals:
An inventory in the form of register for all the chemicals present in a store must be prepared & updated.
This inventory must be submitted by the store in-charge to his seniors on monthly & yearly basis. This inventory should contain all the information of all the chemicals which are being used in that specific premises, material safety data sheets, chemical formulas of chemicals, precautions of chemicals must also be present and written in the inventory.
Chemicals must be disposed off (old & un-used) according to the EHS and OSHA regulations and by following the chemical waste requirements in terms of safety.
5.2 Dry chemical storage:
In case of dry chemicals, segregate and separate the organic and in-organic materials and also store them separately.
5.3 Liquid chemical storage:
In case of liquid chemicals, first of all determine major storage groups (acids, bases, etc).
Then store highly toxic chemicals separately.
Segregate the chemicals according to their hazards and their physical & chemical properties. The principle of segregation is that “store different groups of chemicals or chemicals separately from each other”.
To store different chemicals in a same store, small compartments are made and chemicals are stored in them according to their properties and hazards caused by them. It is known as compartmentalization.
Labeling of all the containers, cartons etc is very important.
- Write down simple names of chemicals inside the containers.
- Never use any abbreviation or chemical formula on the label
- Store the chemicals according to the label of chemicals.
Documentation of all the chemicals and record Keeping is very necessary for safe chemical storage. The details of accumulation area of chemicals, material safety data sheet, training record regarding chemicals and audit form of chemicals etc must be recoded & written record must be compiled & maintained.
5.8 The 5-S of Good Housekeeping:
For safe storage of chemicals and for the purpose of good housekeeping, the following 5-S formula of good housekeeping must be followed which is as under.
- S- sort.
- S-set in order.
- S- shine.
- S- sustain.
5.9 General Instructions:
- Separate acids from bases.
- Separate acids and bases from flammables.
- Separate flammables from oxidizers.
- Store flammable liquids separately.
- Store corrosive materials separately.
- Store reactive materials (oxidizers & reducers separately).
- Store gas cylinders separately.
- Store thermally unstable materials in cool place.
Classification of Chemical Emergencies:
Simple Spill — one which you can safely clean up yourself.
Major Emergency or High Hazard Spill — one which you cannot safely clean up yourself.
This is a point in industrial premises & any other place of handling or storage of chemicals where any person affected by the chemicals can wash his affected area of body with tap water. These points must be marked at various locations in the industrial set ups & chemicals handling places. The affected part of the body must be flushed for 15-20 minutes with tap water if affected.
7.1 Chemical emergency response:
- In case of chemical emergency:
- Call emergency services like Rescue 1122.
- Evacuate the area.
- Inform your seniors and other people.
- Try to wash affected part of the body with tap water for 15-20 minutes.
- Consult material safety data sheet for safety precaution and initial first aid.
- For spill on clothing, skin, remove clothes, wash with soap & water, consult MSDS & seek medical advice.
- Safety Measures for acids, Bases & Alkali metals:
- Concentrated Nitric acid (HNo3) & sulfuric acid (H2so4) are very dangerous.
- Acids need to be handled with care.
- Acids can damage the skin and are corrosive in nature.
- Acids can produce toxic gases.
- Use DCP, sand & as a last option, use AFFF for firefighting on acid fire incidents.
- Bases are also very dangerous in nature.
- Caustic soda (NaoH) and caustic potash (KoH) are extremely dangerous.
- These bases are mostly water reactive.
- Bases produce heat.
- Most of the bases are not flammable.
- Use DCP, sand & as a last option use AFFF foam for firefighting on bases.
- Alkali Metals:
Lithium, sodium, potassium etc are known as Alkali metals. These are water reactive in nature.
React vigorously with water and from hydroxide.
Some kept in kerosene oil and ignite when exposed to air. Dry powder must be used for firefighting of all alkali metals.