ABC of Safety in the Biological Sciences




Giemsa stain is a mixture of azur A eosinate, azur B eosinate, methylene blue eosinate and methylene blue chloride dissolved in methyl alcohol with glycerol as a stabiliser.

Dark greenish­black powder. Quinone­imine group of dyes.
Heating produces toxic fumes of nitrogen, sulphur and bromine compounds.
There is no data available on the effects of this compound dye on humans. However, methylene blue is a mutagen, very toxic and an irritant whilst eosin is an animal carcinogen and an eye and skin irritant (see Methylene blue and Eosin, this Section). Giemsa stain should therefore be handled with due care. The powder is combustible and should not be handled close to heat or a naked flame.
Use a fume hood when handling the powder.
Potential carcinogen.
Suspect mutagen ­ the powder should not be handled by staff who are pregnant.
Avoid skin and eye contact.
Avoid inhalation or ingestion of the powder.
Keep away from heat.
Wash hands thoroughly after handling.
Use a fume hood to keep the level of exposure to a minimum. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard.
Skin ­ remove contaminated clothing then immediately wash the affected area with soap or mild detergent and large amounts of water until all evidence of the dye has been removed (approximately 15 minutes). If irritation persists or dermatitis develops seek medical attention. Wash contaminated clothing before re­use.
Eyes ­ immediately wash the affected eye with large amounts of water until all evidence of the dye has been removed (approximately 15 minutes). If irritation or pain persist seek immediate medical attention.
Inhalation ­ remove from the area of exposure to fresh air. If breathing has ceased apply artificial respiration. Give oxygen of necessary. Keep warm and allow to rest. If irritation or discomfort persist seek medical attention.
Ingestion ­ wash the mouth thoroughly with water and give two to four glasses of water to drink. If the victim is conscious induce vomiting by touching a finger to the back of the throat. Seek immediate medical attention.
Store in a cool, dry atmosphere away from heat.
Butyl rubber gloves, laboratory coat and self contained breathing apparatus.
On skin and clothing: wash skin with strong soap solution immediately. Rinse thoroughly. Contaminated clothing should be removed, dried and washed with strong soap solution or destroyed. It may be necessary to destroy shoes by burning.
Small spills: absorb liquid on paper towels. Brush solids on to paper. Place in an iron pan and allow evaporation in a fume hood. Add crumpled paper and burn. Wash spill site with a strong soap solution.
Large spills: cover with sand and soda ash mixture (90/10). Mix and shovel into a cardboard box. Pack with a large excess of crumpled paper. Burn in an open pit or incinerator equipped with an afterburner and scrubber.
1 Pour or sift on to a thick layer of sand and soda ash mixture (90/10). Mix, and shovel into a heavy paper box with much paper packaging. Burn in an incinerator. The fire may be augmented with scrap wood. Stay on the upwind side.
2 Dissolve in a flammable solvent and spray into the firebox of an incinerator equipped with an afterburner and scrubber.


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