ABC of Safety in the Biological Sciences
CHROMIUM TRIOXIDE (CRO3)
SYNONYMS
Chromic acid, chromic anhydride.
CHARACTERISTICS
Dark red, deliquescent crystals or flakes.
INCOMPATIBILITY
Chromium trioxide is incompatible with bases and reducing
material causing fire and explosion.
HEALTH HAZARD DATA
This substance can spontaneously combust. It is a strong
corrosive substance and can cause severe burns. Kidney damage
can result from ingestion. It is a strong oxidising agent and
whilst it is not normally combustible it will support
combustion. It can be absorbed into the body by inhalation and
ingestion. Acute exposure to the skin and eyes causes redness,
pain and localised burns. Blurred vision may result. Intensive
contact with skin may cause dermatitis. Inhalation may produce
sore throat, coughing, shortness of breath and laboured
breathing. Ingestion may cause sore throat, abdominal spasm,
vomiting and diarrhoea. Potential carcinogen.
HANDLING and GENERAL PRECAUTIONS
Use a fume hood.
Avoid skin and eye contact.
Avoid inhalation or ingestion of the powder.
Keep away from heat.
Keep away from reducing materials.
Keep the lid tightly sealed.
Wash hands thoroughly after handling.
Use a fume hood to keep the level of exposure below the
recommended threshold limit, i.e. 0.05 mgm3. If exposure is
expected to exceed this limit then a respirator is recommended.
Wear protective clothing. A long sleeved laboratory coat or
gown, rubber gloves, safety goggles and a face mask as a minimum
standard. When making an aqueous solution, if there is any
danger of a splash to the face occurring, wear a full face
shield.
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). If
burns develop seek medical attention. Wash contaminated clothing
before reuse.
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 persists or vision is
blurred seek immediate medical attention.
Inhalation remove from the area of exposure to fresh air. If
breathing has ceased apply artificial respiration. Sit in a half
upright position and seek medical attention.
Ingestion rinse the mouth thoroughly with water and give water
to drink. Seek immediate medical attention.
STORAGE
Store in a cool, dry atmosphere away from combustible substances
and reducing agents.
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:
1. 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.
2. 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 3M 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 3M 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
BACK to the
top of the Glossary Contents List
BACK to the top of the
Chemical Contents List