Dear Mike,
Comment by another colleague is correct, you can use UV Lamps; these are
usually factory fitted, but can be done by your engineering staff. There are
however a couple of points that must be born in mind:- viz. 1) the lamps
must be located such that laminar flow is unaffected, which means either
high up on the back or side walls, this can be checked by using a smoke
generator.
2) The lamps will require periodic replacement, whether they appear to be
still working is not an issue, their effectiveness does drop off with age.
The manufacturer of the lamps eg. Oliphant etc. can advise you on a
replacement schedule.
3) If retrofitting the lamps, then get your electrican to wire them in so
that whenever the unit is turned off, the lamps come on automatically. And
always make sure you have the cover in place when turned off.
4) Never operate the unit with the lamps on, or you will risk "Flash-over",
just ask any welder who has had a dose of it!
5) It would be still advisable to use a formaldehyde bomb on a weekly or
forthnightly basis in a busy lab. this would be best undertaken on a Friday
night just about when people are knocking off to go home, ie. last person
out. We have done this in our pouring rooms and flow hoods (Sterile rooms)
for over 10yrs without any inconvenience. There are no cleaning services on
a Friday night in our workplace and we have a tape seal accross the entry
door stating "Fumigation in Progress". An Acid Gas Breathing Apparatus is
provided external to the door in case anyone has to enter the rooms during
the night.
6) Under no circumstances disinfect or clean the unit while it is in
operation, esp. with volatile solvents or formaldehyde, as many of these
units have open bushes and the risk of explosion is very real.

As for the idiots you refer to,  if they don't want to work by the rules
then they can find somewhere else to work. Give them a written warning which
includes a statement of grounds for immediate dismissal and make them sign
the file copy. If they do not follow std. procedures without written
authority again (Anywhere) Sack'em on the spot. They're a danger to
themselves and their colleagues.
Regards Mike (Downunder)
-----Original Message-----
From: Mike Kirby <mikek@mail.saimr.wits.ac.za>
To: HistoNet@Pathology.swmed.edu <HistoNet@Pathology.swmed.edu>
Date: Monday, 7 June 1999 4:42
Subject: Decontamination


>
>Dear Histonetters.
>
>This is more a question for the Microbiologists than Histopathologists, but
>does any one out there know of an alternative method for decontaminating a
>Class II Biohazard Cabinet other than using formaldehyde gas???
>We've got 30 of these "beasts" scattered throught our Organisation and have
>experienced two near fatalities in the past 6 months due to certain "know
>it all" idiots who did not follow our Standard Operating Procedures.
>Thanks in advance.
>
>Mr.M.Kirby.
>Chief Safety Officer
>S.A.I.M.R
>Johannesburg.
>South Africa
>
>
>
>