When remaining vapour has cleared remove night door and beaker. The manual valve should be shut to prevent accidental escape of formaldehyde. Hang the end of the trunking out of a window, or in the basement, place in the fume cupboard. The night door should be sealed with PVC tape and the cabinet fumigated, as above. During the bubbling of the formalin the cabinet fans may be run for 10 seconds on a couple of occasions to ensure adequate dispersal of formaldehyde.
Overnight fumigation allows adequate time for dispersal of formaldehyde by passive means.
Following decontamination the cabinet should be purged of all residual formaldehyde gas. After 10 minutes, the fumigation switch is switched off and the night door removed. The cabinet should then be run for a further 10-15 minutes to remove the last of traces of formaldehyde. 4.6 Motor vehicles Never use a vehicle without permission and if necessary, instruction from an authorised person. Never use a vehicle without first making sure that you are insured to drive it.