SAFETY PROCEDURES

TYPES AND CAUSES OF LABORATORY ACCIDENTS

The first few weeks or even months at least of the time spent in a laboratory should be regarded as an apprenticeship in practical experience.

Remember that carelessness may involve serious consequences for others as well as yourself.

The sources of danger in a laboratory are those due to chemicals and due to the equipment or combination of two.

It is well known that certain chemicals cause serious burns in contact with skin but other chemicals may be more dangerous and yet not give any such warning sensation.

A large proportion of laboratory accidents occur from attempts to get results in too great a hurry.

If you are going to perform an experiment on a bench make sure that the bench is not already crowded with apparatus.

Distraction of attention is another common cause of accidents. If anyone tries to engage your attention while you are doing something either stop your work or wait until you have finished it before you reply.

Do not leave anything on the floor likely to impede the free passage of others and if you spill grease or liquid see that it is wiped up and cleaned immediately.

The accumulation of combustible waste material in the laboratory should not be permitted.

GENERAL LABORATORY OPERATIONS

Following are some comments of safety on points of danger which may be commonly encountered in chemical engineering laboratories:

- Handling glass tubing or rod
- Boring corks
- Glass apparatus
- Gas
- Bottles and other containers
- Ice and ice crasher
- Gas cylinders
- Hydrogen
- Hoods (fume cupboards)
- Flasks under pressure greater or lesser than atmospheric
- Vacuum dessicators
- Vacuum distillations
- Supports
- Transfer and storage of inflammable liquids
- Spillage and residues
- Solvent extractions
- Solvent vapors
- Benzene
- Carbon disulfide
- Ethers
- Aluminum chloride
- Bromine
- Mercury
- Methyl silicate
- Sodium and phosphorus
- Sulfuric acid and corrosive liquids
- Goggles
- Rubber tubing and bungs
- Pipettes

GENERAL LABORATORY SAFETY RULES FOR REDUCING CHEMICAL EXPOSURES IN LABS

• Know all emergency procedures and how to use emergency equipment.

• Use personal protective equipment as required.

• Eating, drinking and smoking in the labs is strictly forbidden.

• Label all containers you fill and replace missing or illegible labels.

• Horseplay is strictly forbidden.

• Safety glasses are mandatory in all lab areas.

• Do not use mouth suction to pipette chemicals or start a siphon: a pipette bulb or aspirator should be used to provide vacuum.

• Use good personal hygiene and wash hands before leaving a lab.

• Use of solvents for washing the skin is forbidden.

• If skin contact with any chemical occurs, wash immediately.

• Chemicals are forbidden in eating areas.

• Never use lab glassware to prepare food.

• It is forbidden to store and/or prepare food in the same equipment used for laboratory operations (i.e.: refrigerators, microwaves, etc.)

• Spills must be cleaned up immediately and disposed of properly.

• Contact lenses are not permitted to be worn in laboratories.

• Never smell or taste a chemical to identify it.

TOXIC AND DANGEROUS CHEMICALS

BENZENE
is an inflammable as light petroleum and is much more toxic. No concentration of vapor however small can be considered safe over long periods.

CARBON DISULFIDE
is one of the most inflammable of common solvents and also poisonous. A steam pipe or electric bulb may ignite it.

ETHERS
Diethyl ether is exceedingly inflammable. Diethyl and isopropyl and also higher ethers may form explosive peroxides. They must be kept in dark bottles.

ALUMINUM CHLORIDE
Bottles should be opened with great caution particularly when they have been stored after partial use. It is liable both to cause stoppers to stick and to develop pressure by formation of hydrogen chloride which may burst the container.

BROMINE
is poisonous and can cause burns. Bottles containing bromine fracture because of its great density.

MERCURY
Its poisoning is insidious and produces nervous tremors more frequently than is realized. Metallic mercury is toxic and if it is necessary to leave a surface of mercury exposed in any vessel there should be a layer of water or other non-toxic liquid on top of mercury.

METHYL SILICATE
should be handled cautiously as its vapor can cause serious eye injury or even permanent blindness.

SODIUM and PHOSPHORUS
Sodium which should be stored under paraffin or naphta should not be kept near yellow phosphorus which is stored under water. Sodium residues often become coated with a layer of hydroxide or carbonate and are all more dangerous on this account. Residues should be destroyed with methlylated spirit even when they look as if exhausted.

SULFURIC ACID and CORROSIVE LIQUIDS
Fuming sulfuric acid demands particular care. Acid splashes should always be washed off with water before attempting neutralization with sodium bicarbonate solution. Corrosive chemicals must not be handled in large fragile containers.

SAFETY AS YOU LEAVE

The following are few things you have to check before you leave the laboratory:

- Is your equipment safely turned down?

- Are all heaters and switches also water and fluid flows to your unit turned off?

- Have you turned the cooling water flow off after the equipment was really cool?

- Have you safely closed all vessels containing volatile chemicals which may have dangerous or hazardous vapor?

If you are the last group leaving the lab:

- Is the steam generator turned off?

- What about the air compressor?

- Do you notice any water flow?