ABC of Safety in the Biological Sciences




Spill kits are essentially decontamination packs which contain all of the materials required to deal with spillage's of particular agents. Commercially available kits include those for acids, caustics, flammable solvents, mercury, hydrofluoric acid and cyanide.

A spill kit designed to neutralise spills of formalin (40% aqueous formaldehyde) on either hard or carpeted floors can be prepared as follows:

  • Component A: a saturated aqueous solution of sodium bisulphite.
  • Component B: a corn starch powder.

Component A combines with formalin which effectively destroys all its irritating, pungent properties. Similarly, formalin attacks the chemical structure of component B leading to compounds which again have none of the original undesirable properties of formalin. The toxicity of the corn starch powder is negligible, however the bisulphite may cause irritation to skin and mucous membranes, but only by direct contact. In a dilute form bisulphite has been used as a disinfectant for skin diseases.22

The kit is used as follows:
On a carpeted surface - drench the spill area with three to five times the volume of component A compared to the volume of formalin spilled. Allow the mixture to stand for several minutes. If a strong odour of formalin remains add more component A. A faint odour of sulphur dioxide may be noticeable in the immediate vicinity of the spill area. This is normal and will disappear very quickly. When the formalin odour has been neutralised add component B to the spill area and allow the powder to absorb the liquid. Remove the moist powder then immediately wash the carpet with an excess of water. After drying there should be no effect on the carpet other than bleaching of the colour.

On a hard surface - completely cover the spill area with component B to prevent any further movement of the fluid. Remove and `bag' the moist powder and apply more of component B if the odour has not been completely neutralised. Traces of formalin remaining in cracks can be removed by wiping the area with component A followed, after 5 to 10 minutes, by washing with water.


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