 |
|
ABC of Safety in the Biological Sciences
BASIC REQUIREMENTS
The following gives basic recommendations for common hazards faced by a laboratory worker. It is essential that all personnel develop a thorough knowledge of these for their own protection as well as the protection of colleagues.
Laboratory Chemicals
There needs to be an awareness of the potential hazards, fire risk and toxicity associated with every chemical used in the laboratory. Material safety data sheets, provided by manufactures on request, contain safety related information. A complete list of hazardous substances and relevant safety related data is required by law, in some countries, to be kept in the workplace.1,2,5,6
All chemicals present some degree of danger because of toxicity, irritation or the flammable nature of the substance. Toxicity and irritation can be caused by inhalation, skin contact or ingestion of solid, liquid or vapour. Examples of some of the more commonly used agents and their associated hazards include the following:
- Absolute ethyl alcohol is flammable and within one minute, after 4 litres is spilled and ignited, the ceiling temperature reaches 500oC9
- 10 ml of isopropyl alcohol, ingested, can cause death.9
- Chloroform and 40% formalin are volatile liquids with vapours that are highly toxic when inhaled. Both can also cause skin irritations. Formalin is also a potential carcinogen.9
- Xylene is flammable and can cause severe skin irritations as well as central nervous system disorders.9
Handling potentially infective material
All human material should be handled as though potentially
infectious, even if received in fixative. Not only may viable
organisms be present because of inadequate or insufficient fixation
but some agents, notably those responsible for the spongiform
encephalopathies such as Creutzfeldt-Jakob disease, can withstand
formalin fixation. When handling tissues always wear protective
clothing comprising a long-sleeved laboratory coat or gown with
elasticised wrist bands, rubber gloves and safety glasses. As well
as from contact with contaminated material, infection can also occur
from aerosols created by splattering or spilling contaminated fluids
or simply from opening a container which may release droplets of
moisture which then circulate in the air.
It is advisable for all personnel who handle fresh biological
material to be immunised against hepatitis B. In addition it is
recommended that personnel working with animals be immunised against
anthrax and those in contact with chimpanzees be immunised against
hepatitis A virus. An immunisation policy should form part of the
occupational health and safety strategy for each laboratory.
The location and use of safety equipment
Panic is often the first reaction to accident induced trauma. Those
who receive appropriate, regular instruction in safety procedures,
including evacuation and fire drills, tend to remain calm and in
control.
A safety shower should be provided within any laboratory where
poisonous, corrosive or flammable chemical substances, especially
strong oxidising or reducing agents, are handled regularly.10
The shower is used to dilute and remove chemicals splashed on to the
body or clothing, as well as to extinguish clothing fires. The
location of the safety shower should be clearly marked and all staff
made aware of its location and instructed in its use. The safety
shower must be checked regularly to determine that it is working
correctly. If a safety shower is not available in the immediate
vicinity staff should be made aware of the location of the nearest
shower facility that is available for emergency use. If neither is
available in an emergency a hose, fitted with a spray nozzle and
which will fit at least one tap in the laboratory, can provide an
alternative. The Australian Standard for safety showers recommends
the provision of a minimum of 135 litres of water per minute at low
velocity to avoid further damage to body tissues. Valves should
require a positive action to shut off. Showers should be less than
10 metres travel distance from any point in the laboratory and have
unobstructed access.11
Eye wash equipment should be provided, in the form of an eye wash
bottle or continuous flow facility (see eye wash facility). The
location of this equipment should be known to all laboratory
personnel. Staff should also be familiar with the position, type and
operation of the nearest fire extinguisher and learn what other fire
and safety equipment is nearby.
Basic emergency procedures
Chemical splash to the eye12
Wash the eye immediately in gently flowing, cold water (wash bottle
or continuous flow eye wash facility) for a minimum of 15 minutes.
The eye must be kept open during flushing. At this time it is
essential to obtain appropriate advice about any possible hazard to
the eye from the chemical concerned.
Speed is crucial, a 30 second delay between the splash and the
initial flush can lead to permanent eye damage especially if the
victim is wearing contact lenses.
Never flush an eye with dilute acid or dilute alkali to 'neutralise'
a chemical as these agents can cause more severe damage. Never
wear contact lenses in a preparation area or where an eye splash is
a possibility.
Chemical splash to the body12
Small splash - flush the area with cold water for a minimum of 15
minutes. Warm or hot water should not be used as this may facilitate
the absorption of chemical substances through the skin. Vapour from
hot water can also carry chemical particles which may be inhaled.
Large splash - wash the victim with a safety shower or hose for a
minimum of 15 minutes. Clothing should be removed during and not
before the shower.
For skin contamination, wash the affected area with a large
volume of water for at least 15 minutes until all evidence of the
chemical has been removed.
Contaminated clothing should be washed before re-use.
In case of fire or explosion13
All institutions should have a procedure to follow in case of fire
occur. Personnel should familiarise themselves with the contents of
the fire plan for their area. If a fire plan does not exist it
becomes the responsibility of the safety officer or the laboratory
manager to prepare one. Staff who receive regular (annual) training
in fire safety tend not to panic in an emergency.
The fundamentals of a fire plan are as follows:
- close the door leading to the fire
- raise the alarm by calmly notifying the appropriate authority of the exact location of the fire or call the fire brigade
- select the correct type of fire extinguisher for the class of fire
- attempt to put out the fire using the correct type of fire extinguisher for the type of fire
If the fire has developed beyond the stage where it can be controlled with an extinguisher and if time allows
- turn off all gas outlets and electrical appliances
- close the door
- ensure that the area is evacuated and wait for your fire team, safety officer or fire brigade to direct them to the fire
At this point your responsibility should end unless you are
directed to perform some action by the fire team controller, safety
officer or a member of the fire brigade.
Assembly point
A pre-designated area which does not interfere with access by fire
fighters, is used as an assembly area. All personnel should remain
in the pre-designated area until their names have been checked off
against a staff list. One member of the staff, and a deputy, should
have the responsibility for this procedure. In order to make staff
aware of their responsibilities and the procedure to follow in the
event of a fire, at least two practice fire safety evacuations of
buildings should be performed each year.
Each member of the staff should be able to quickly answer each of the following questions:
- Where is your nearest fire escape?
- Is it readily accessible?
- Is any operation of mechanics required?
- Do you know how to operate the fire escape?
Fire extinguishers
Never use water or foam fire extinguishers on combustible metal
fires or where there is live electrical equipment. If water is
applied to a fire involving combustible metals (magnesium, lithium,
sodium, aluminium, potassium, titanium or zirconium) it can burn
rapidly and violently, becoming increasingly hotter and difficult to
control. For each class of fire there is a particular, recommended
fire extinguisher (see
TABLE 1).
Fire extinguishers, must receive at least one annual safety check
to ensure that they will work in an emergency. Safety checks are
generally carried out by local fire authorities.
Allow staff to learn how to use fire extinguishers so that in an
emergency they are familiar with the application.
Safety blankets are suitable for use on small, contained fires and are effective in suppressing flames when wrapped around a person whose clothing is alight. They should be installed in laboratories in a conspicuous location with ready access, preferably at eye level.
Prevention
Consideration should be given to fire prevention inspections at
least every three months in conjunction with practice fire
evacuations at least every twelve months (two per year is
preferable).
Some priorities would be to:14
- reduce the level of combustible and flammable material to a minimum in the laboratory (supply for one day should suffice)
- store combustible materials in purpose built storage areas
and not in the laboratory
- eliminate ignition sources where combustion might occur (install spark-proof switches in fume hoods and refrigerators, remove all naked flames from the work area wherever possible and eliminate sources of static electricity)
- provide staff training in procedures which reduce fire hazards
- do not use fume hoods as storage areas for flammable solvents
Points to note during a fire prevention inspection include the following:
- clear floors, passage ways and escape routes
- storage of flammable solvents
- storage of combustible materials
- clean and tidy storage areas with spaces between incompatible substances and combustible materials
- evacuation procedures
- fire control training
- siting of gas cylinders
- fully maintained and appropriate fire fighting equipment and siting of the fire fighting equipment
- spark arresters in high risk areas
-
waste management for combustible materials and flammable solvents
BACK to the top
of the Glossary Contents List
BACK to the top of the Chemical
Contents List