ABC of Safety in the Biological Sciences
PERCHLORIC ACID (HCl04)
SYNONYMS
None known.
GENERAL PRECAUTIONS
Use a fume hood.
Highly toxic through all routes of exposure.
Causes permanent eye damage.
Keep away from oxidising materials.
Keep away from hydroxyl compounds.
Keep away from organic material.
Wash hands thoroughly after handling.
HEALTH HAZARD DATA
This substance can form explosive perchlorate esters with many
hydroxyl compounds. In the presence of combustible or reducing
materials it is very unstable and can produce violent
explosions. It is highly toxic via all routes into the body and
a splash to the eye can cause permanent eye damage. It is a
corrosive substance and can cause severe burns.
TREATMENTS
Skin remove contaminated clothing and immediately wash the
affected area with large amounts of water until all evidence of
the chemical has been removed (approximately 15 minutes). Apply
a magnesia/glycerol paste to the affected area and in severe
cases seek immediate medical attention. A magnesia/glycerol
paste should be in your first aid kit if perchloric acid is
handled in your laboratory. It is available off the shelf in
pharmacies.
Eyes immediately wash the affected eye with large amounts of
water until all evidence of the chemical has been removed
(approximately 15 minutes). If pain or blurred vision persist
seek medical attention.
Inhalation remove from the area of exposure to fresh air. If
breathing has ceased apply artificial respiration. Keep warm and
allow to rest. If irritation persists or signs of toxicity
develop seek medical attention.
Ingestion wash out the mouth thoroughly with water and give
water to drink followed by Milk of Magnesia. If signs of
toxicity develop seek immediate medical attention. Milk of
Magnesia should be part of your laboratory first aid kit if
perchloric acid is handled in your laboratory. It is available
off the shelf in pharmacies.
INCOMPATIBILITY
Heating produces toxic fumes of chlorine compounds.
Perchloric acid is incompatible with acetic anhydride or other
dehydrating agents.
Nitric acid and cellulose material explosive.
Hydroxyl compounds explosive.
Dimethyl sulphoxide explosive.
Ketones and glycols violent reactions.
Ferrous sulphate explosive.
Reducing agents explosive.
STORAGE
Store in a cool, dry atmosphere away from heat and incompatible
substances.
HANDLING
This is a highly toxic substance use a fume hood to keep the
level of exposure as low as possible. Wear protective clothing
to avoid any sort of bodily contact. A long sleeved laboratory
coat or gown, rubber gloves, safety goggles and a face mask as a
minimum standard. The fume hood should be constructed of
noncombustible materials.
DISPOSAL
WEAR:
Rubber gloves, face shield and laboratory coat. A body shield
should be available for the more active agents. Replace the face
shield with self contained breathing apparatus for such agents
as chlorine and bromine.
SPILLS:
Gas leak: if the valve is leaking because it cannot be closed,
the gas can be bubbled through a reducer (sodium sulphite) and
excess sodium bicarbonate solution. Be sure to include a trap in
the line to prevent the solution being sucked back into the
cylinder. If this cannot be done the cylinder should be placed
in or adjacent to a fume hood and left to bleed off. If the leak
is in the valve assembly, a plastic bag can be fastened over the
head of the cylinder which can then be taken outside or to a
fume hood.
Liquid or solid: cover with a reducer (sodium thiosulphate, a
bisulphite or a ferrous salt not carbon, sulphur or strong
reducing agent). Mix well and spray with water. A sulphite or a
ferrous salt will require addition of 3mol/l sulphuric acid to
promote a rapid reduction. Scoop the slurry into a container of
water and neutralise with soda ash. Discharge to sewer with a
large excess of water. Wash the site thoroughly with a soap
solution containing some reducer.
PACKAGE LOTS:
Add to a large volume of concentrated solution of reducer
(sodium thiosulphate, a bisulphite or a ferrous salt and acidify
with 3mol/l sulphuric acid). When the reduction is completed add
soda ash or dilute hydrochloric acid to neutralise the solution.
Discharge to sewer with a large excess of water.
ENVIRONMENT:
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