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ABC of Safety in the Biological Sciences
BURNS
Burns in laboratories can be from chemicals, hot surfaces, flames or cryogenic liquids.
General treatment
- to relieve pain and swelling flush with cold water then apply cold water compresses
- do not lance blisters
- do not apply any lotions, ointments or oily dressings
- always obtain medical attention for all but the most superficial burns. Fluoride burns, in particular, always require medical treatment
Specific injury treatment
If necessary:
1. Remove or cut away clothing over the burned
area but leave clothing that is stuck.
2. Flush liberally with cold water.
3. Cover the burned area with a sterile or
clean dressing.
Chemical Burns
1. Wash off chemical immediately with a large
volume of water-use a safety shower if available.
2. Flush splashes out of the eyes with an
ophthalmic irrigator or by holding the face under a stream of cold
water. Ensure that all chemical is flushed from under the eyelids.
3. Remove contaminated clothing.
4. Cover the burned area with a sterile
dressing.
Cryogenic liquid burns (cold contact
burns)
Tissue damage does not normally occur
immediately upon contact with a cryogenic liquid. Initially, the
blood supply to the tissue acts as a heat source and creates a
heat-insulating gas film at the liquid/tissue interface. This time
delay is usually sufficient for severe injury to be avoided even
when a large volume of fluid is involved, provided that appropriate,
subsequent action is taken.36
If cryogenic fluid is splashed onto the body, immediately flush the affected area with water and remove any saturated clothing. It is especially important to remove gloves or footwear quickly if liquid is splashed into them, as large volumes can be trapped inside enhancing the risk of tissue damage by prolonged contact.
The high heat capacity of water, its harmlessness and ready availability all combine to make it an important safety factor in cryogenic operations. If practicable, water should be made readily available wherever cryogenic liquids are handled. All bulk storage installations should include a safety shower.
If, despite initial treatment, cold contact burns are inflicted, the overriding first aid considerations are to remove the casualty to hospital quickly and, if the burns are severe, to avoid thawing the affected area before admission. Always seek professional medical attention for cold contact burns as these carry a risk of tissue necrosis.
Irrespective of severity, general first aid rules are:
- do not rub or massage affected area
- do not expose to a radiant heat source
- do not allow the casualty to smoke, or to drink alcoholic beverages
Common sense safety dictates the use of:
- tongs to remove material immersed in fluid
- personal protective clothing-a long sleeved laboratory coat or gown with elasticised wrist bands, a full face shield, leather gloves and footwear impervious to the cryogenic fluid
- well-ventilated areas
- cryogenic vessels specifically designed for low temperature fluids
Asphyxiation
If a person begins to exhibit signs of
asphyxia while working with cryogenic liquids, remove him or her to
a well-ventilated area immediately. If breathing has stopped, apply
artificial respiration. If the oxygen level is depressed to below
about 15 per cent v/v in air or the gas is toxic, the rescuer will
need to wear a self-contained or supplied air respirator. In sudden
and acute asphyxia, such as that from inhalation of pure nitrogen,
unconsciousness is immediate and death may occur within a few
minutes.
Where asphyxia develops slowly by gradual reduction of the oxygen content in the air, early outward signs are the inability to think clearly, disturbance of muscular coordination, rapid fatigue and easy arousal of emotions, particularly ill-temper. If the oxygen reduction becomes severe, complete physical collapse may occur. The victim may be unaware that anything is wrong until beyond self-rescue or the summoning of aid. A respirator should be available wherever large volumes of cryogenic liquids are handled.
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