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Chemical Safety
Working with potentially hazardous chemicals is an everyday occurrence in a laboratory setting. Hazardous
situations can occur if users are not educated in general chemical safety, toxicological information, and
procedures for handling and storage for the chemicals they are using. This section spells out specific protocols
to minimize hazardous chemical exposures.
The dangers of chemical hazards are:
4.1
4.2
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Health: Chemicals can enter the human body by inhalation, injection, skin absorption or by ingestion
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Fire: Some chemicals are very flammable when can easily cause fire
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Reactivity
Materials Safety Data Sheet (MSDS)
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MSDS contains information on chemical identification, composition, and physical properties along with
health, physical, and environment hazards. Other sections include emergency, first aid and handling and
storage procedures. The MSDS will discuss engineering controls for handling materials, and personal
protective equipment that should be used. Some also provide stability and reactivity information, toxicology,
ecological information, disposal considerations, transport and regulatory information.
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All chemicals purchased must come with the Materials Safety Data Sheet (MSDS).
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Lab users MUST READ THE MSDS and understand the hazardness of chemical before use. All lab users
should know how to access manufacturer specific MSDSs for the chemical they work with.
Basic Chemical Handling and Storage Procedure
General Safety Practices
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Keep the work area clean and uncluttered
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Do not leave exposed sharps (needles, razor blades, etc.) unattended
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Label all containers and keep containers closed when not in use
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Know the locations of fire extinguishers, eye washers and showers
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Wash hands frequently especially before eating
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Clean up all spills promptly
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Wear shoes that completely cover the feet
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Avoid exposure to hazardous materials – wear proper personal protective equipment
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Horseplay, practical jokes, or other acts of carelessness are prohibited
Chemicals Handling and Storage Procedures
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Minimise all chemical exposures. Approach all chemicals as hazardous and use common sense – do not
taste chemicals, avoid smelling chemicals and do not mouth pipette.
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Protective glasses or goggles should be worn in the laboratory. Non-vented goggles should be worn when
working with acids, caustics, explosives, or hot molten materials.
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Wear proper gloves when working with any hazardous or potentially hazardous materials.
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Warning signs should be posted near any dangerous equipment, reaction or condition.
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Use fume hoods and other ventilation devices to control exposure to airborne substances
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4.3
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All containers must be labeled with chemical name, concentration and hazardous warning.
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Store chemicals by compatibility. It is also acceptable to alphabetize with compatibility groups.
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Do not store materials in the fume hood or on the floor.
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Flammable materials must be stored in approved containers.
Waste Chemical Disposal
General Classification of Chemical Wastes
In general the chemical wastes in the labs can be divided into the following categories:
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Inorganic acids (e.g. Hydrochloric acid, Nitric acid, Sulphuric Acid and Hydrofluoric acid)
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Organic Acids (e.g. Acetic Acid, chromic acid)
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Non-chloro-Organic Chemical (e.g. acetone, alcohol and Tetrahydrofuran)
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Chloro-Organic Chemicals (e.g. Chloroform and Carbon Tetrachloride)
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Solid Waste (e.g. Polymers and Inorganic fillers)
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Reactive Substances (Sodium, hydrides of alkali metals, phosphorus compounds)
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Waste Oil ( Silicon Oil, Vacuum Pump Oil)
General Guidelines for Chemical Waste Disposal
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Chemicals of the same category can be disposed into the same waste container.
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DO NOT mixed chemicals of different categories. It may result in explosion!
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All the waste bottles must be clearly labeled.
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The name and amount of waste chemicals must be recorded each time when they are poured into waste
bottles.
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Those who use chemicals must have sufficient knowledge on their safety handling and disposal. They
should read MSDS and consult trained personnel when in doubt.
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Undergraduate students are not allowed to handle any hazard chemicals unless they are under close
supervision.
Guidelines for Disposal of Spent Acids & Bases
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All the inorganic acid waste solutions must be neutralized or diluted until their pH ≥ 2 before being disposed
into waste bottles.
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After neutralization, the acids should be stored in plastic bottles.
Do not store HF in Glass bottles.
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Bottles used for storage of organic chemicals can not be used for storage of inorganic acid wastes.
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Neutralization of acids should be carried out based on quantitative calculation. Neutralization is a very
vigorous reaction, which may generate a large amount of heat (Always acid to water, not water to acid).
Stirring and cooling is required for large-scale neutralization.
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Neutralization must be done by trained personnel. Undergraduate students are not allowed to handle it
unless they are under close supervision.
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Aqueous corrosive wastes shall not contain sulfides, cyanides, metals, or other materials that can give off
hazardous fumes upon reaction with the acid or base.
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Guidelines for Disposal of Organic Chemicals
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All the organic chemicals, no matter chloro- or non-chloro, should be stored in glass bottles.
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Some organic chemicals are highly reactive and hence cannot be disposed directly without treatment.
Those who use such chemicals must have sufficient knowledge on their safety handling and disposal. They
should read MSDS and consult trained personnel when in doubt.
Guidelines for Disposal of Solid Wastes
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Solid chemical wastes should be stored in a container strong enough to withstand the weight of the waste.
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Broken glassware & needles should be disposed in a separate bin marked with “sharps”.
Guidelines for Disposal of Other Special Chemicals
Based on our records, the following chemicals are frequently used in SME labs.
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Developer, fixer, photoresist
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perchloric acids
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mercury
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Copper Sulphate solution
Each of the above wastes must be placed in a separate bottle and clearly labeled.
Guidelines for Disposal of Highly Reactive Substances
The following chemicals must not be disposed before proper treatment:
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waste sodium and other alkali metals
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hydrides of alkali metals
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phosphorus compounds
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concentrated acids
Each lab should have their own specific procedures for disposal of special chemical wastes produced
in their lab., e.g. mercury solid wastes, radioactive or bio-active chemicals
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