ABC of Safety in the Biological Sciences - Sodium Nitroprusside

 

ABC of Safety in the Biological Sciences

 


 

SODIUM NITROPRUSSIDE [Na2(Fe(CN)5NO).2H2O]

SYNONYMS
Sodium nitroferricyanide.
GENERAL PRECAUTIONS
Very toxic, avoid inhalation or ingestion.
Use a fume hood.
Avoid eye contact.
Keep away from heat.
Keep away from nitrites.
Wash hands thoroughly after handling.
CHARACTERISTICS
Ruby red crystals or crystalline powder.
HEALTH HAZARD DATA
This is a highly toxic compound, the lethal dose is 11 mg per kg of weight for humans. This dose can be by inhalation or ingestion of the powder. It causes a rapid fall in blood pressure with subsequent death. It is also an eye irritant. The effect of this chemical upon skin has not been documented. Treatment for cyanide poisoning must be effected rapidly to ensure recovery.
TREATMENTS
A cyanide poisoning treatment kit should be available in all laboratories which handle cyanides. The kit should contain:
(i) Amyl nitrate ampoules to be administered by inhalation. One ampoule every 5 minutes. Stop administering if the systolic blood pressure falls below 80 mm of mercury.
(ii) 3% Sodium nitrite solution for intravenous use. Inject at the rate of 2.5 ml to 5 ml per minute.
(iii) 50% Sodium thiosulphate solution for intravenous use. Inject at the rate of 2.5 ml to 5 ml per minute.
(iv) Cobalt edetate for injection to induce vomiting.
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 irritation or pain persist seek immediate 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 irritation or pain persist seek immediate medical attention.
Inhalation ­ wear breathing apparatus then remove the patient from the area of exposure to fresh air. Remove all clothing then break a capsule of amyl nitrate and allow to inhale for 15 to 30 seconds. If the victim has ceased breathing apply artificial respiration to help with the inhalation of amyl nitrate. 100% Oxygen can also be administered. If medical assistance is not readily available administer intravenously 10 ml of 3% sodium nitrite solution at the rate of 2.5 ml to 5 ml per minute. Send someone for medical assistance. Wash any contaminated clothing before re­use.
Ingestion ­ as for inhalation.
INCOMPATIBILITY
Heating produces highly toxic fumes of nitrogen compounds and cyanides. Sodium nitroprusside forms explosive mixtures with nitrites when heated.
STORAGE
Store in a secure place that is cool and dry.
HANDLING
Use a fume hood that will keep the level of exposure low and offer protection from inhalation of the dust. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard. If levels of exposure are expected to be high then a respirator or self­contained breathing apparatus is recommended. Use care.
DISPOSAL
WEAR:
Long rubber gloves, self contained breathing apparatus and laboratory coat.
SPILLS:
Eliminate all sources of ignition.
1 General treatment.
Absorb the liquid with vermiculite or on paper towel. If a solid sweep on to paper towel. Place on an iron or glass dish in a fume hood. Evaporate and burn the paper.
On skin: immediately wash the affected area with soap and a large amount of water.
2 Hydrocyanic acid leak.
Turn on the fume hood. allow the gas to leak into a container of sodium hydroxide solution while stopping the leak. Add excess calcium hypochlorite to the alkali cyanide. discharge to the sewer with a large excess of water.
3 Cyanides.
Scoop into a large beaker and make alkaline with sodium hydroxide solution. Add to the slurry an excess of ferrous sulphate solution. After one hour discharge to the sewer with a large excess of water.
4 Nitriles.
Add an excess of calcium hypochlorite solution to produce a cyanate. Scoop the slurry into a large beaker. After one hour discharge to the sewer with a large excess of water. Wash the spill site with a soap solution containing some hypochlorite.
PACKAGE LOTS: Either
1 Add with stirring to strong calcium hypochlorite solution. Allow to stand for 24 hours then discharge to the sewer with a large excess of water.
OR
2 Liquid nitrile can be mixed with a flammable solvent and spraye
d into an incinerator equipped with an afterburner and scrubber. ENVIRONMENT:

 


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