interactions (SUVA, 2015; Teuschler and Hertzberg, 1995) the
chemical under authorization and/or the by-products might have
with other chemicals.
In the lethal toxic osmium tetroxide (OsO4) example, it has
been agreed that the work will only be carried out by an authorized
person in a confined fume hood located in a laboratory
with positive pressure differential designed to prevent migration
of contaminants. Only one person equipped with a lone-workersafety-device
is allowed to work in there. To further reduce the
risk of uncontrolled chemical contaminants leaving the working
space, the laboratory has been subdivided. This was achieved
by putting a special mobile room divider that creates a barrier
between the working area and a small space before the exit
door. In this way, the authorized person working in the laboratory
benefits from a clean area within the laboratory itself before
entering the working area. This is also beneficial in the case the
operator has to leave the room for emergency reasons as the
hazard left behind the barrier will be separated from the
entrance.
Even if strategic protective measures, like changing to a safer
protocol or by automating a hazardous process, can be implemented
to minimize the exposure risk, the user will have to wear
the correct type of equipment to protect his entire body efficiently
from the substance and/or the energies (laser, UV, heat, pressurised
gases, etc.) required during the process. Bearing in mind that this
authorization procedure also aims at educating people, the colleagues’
knowledge about Personal Protective Equipment (PPE)
and how to wear them properly will be checked at this point. As
no universal PPE exists, a research might have to be carried out
to find the required and adapted PPEs for each case. The SB-SST
responsible person decides on the appropriate protective measures
to be implemented in agreement with the user. Given the risk that
OsO4 might sublimate accidentally outside the confined ventilated
areas due to a possible leak or a fall and break of the ampoule outside
the fume hood, it has been decided that the user must wear a
respiratory air supply system with full facial protection, as shown
in Fig. 6:
Only when fully equipped the user can take out, from a locked
cabinet inside the fume hood, an ampoule containing OsO4. The
latter is then broken with a special apparatus and the chemical
used in the next step of the established procedure.
The required respiratory protective measure is reported in a
third information sheet (Fig. 7) together with all other required
PPEs:
This third information form will also show information on how
the chemical should be stored and how to dispose of any related
waste. For example, the substance might need to be stored in a
fire-proof cabinet or in an ATEX (ATEX, 2014) approved refrigerator
and/or specifically treated according to its nature before being
thrown into a compatible waste container.
3.4.2. Storage
To ensure a safe storage, the rules about substances’ incompatibilities,
the storage place as well as appropriate labelling to inform
about the presence of the hazardous chemical are discussed.
Then, according to the laboratory’s set-up, the right equipment is
being installed. Legally, all toxic compounds have to be stored in
a ventilated and lockable cabinet to restrict access only to trained
and authorized persons (Swiss ordinances OChim, 2015 and
ORRChim, 2014).
If an expiry date for the chemical is reported or a specific storing
procedure must be followed, as for example always keep an unstable
chemical in a neutral media, the protocol and periodicity are
agreed with the requester. The necessary information is reported
in the document, as shown in Fig. 8:
3.4.3. Waste disposal
Finally the waste disposal is discussed. Very often waste is treated
with less care than the initial chemical or the obtained product.
This is understandable as its value is not comparable with either
one of the latter. However, waste should be treated very carefully,
even more than any other chemical as undesirable reactions may
occur in the container possibly harming the person who produced
it, the colleagues sharing the laboratory or the staff taking care of
it. If the wrong destruction-procedure (temperature, filters, etc.)
is applied, the released fumes will also harm the environment. Furthermore,
if the material of the waste container is not compatible
with the waste it could lead to damage and spill. People receiving
the waste to be packed, transported or destroyed need to know
what the waste is in order to wear the corresponding PPE and
avoid incompatibilities. This is also true for material (glove, tissue,
syringes, etc.) contaminated with the substance subject to authorization.
Thus it is mandatory to use the right container and label
it with the description of waste (SB-STT website, Swiss ordinances
DETEC, 2010 and OMoD, 2014).
Given the fact waste resulting from the use of osmium tetroxide
is also hazardous, it i