OHS017
OHS Risk Assessment and
Control Form
Faculty/Division: Medicine
Document number
SOMS.CGM.RA037
Initial Issue date
26-June-2009
Risk assessment completed by: Teresa Bonello
Staff/student number: 3286547
Current version
1.0
School/Unit: School of Medical Sciences
Current Version
Issue date
26-June-2009
Next review date
26-June-2012
For additional information refer to the OHS Risk Assessment and Control Procedure, the OHS Risk Rating Procedure and the Hierarchy of Risk Controls.
Risk Assessment title:: MTT Viability Assay
Step 1: Identify the activity
1.
Prepare MTT stock concentration of 2mg/ml from powder in PBS. Filter sterilize and store at 4°C.
2.
Plate mammalian cells at the required density in a 96 well plate, and allow cells to adhere for 24hrs at 37°C and 5% CO2 before proceeding with assay.
2a. Optional*: Treat cells with cytotoxic compound of interest, diluted serially over an 8 log range of concentrations.
3.
Add 50μl MTT stock solution directly to the cells in culture medium and incubate at 37°C with 5% CO2 for 4hrs.
4.
Aspirate media from wells. Add 100μl DMSO to each well to solubilize the purple precipitate and mix solutions thoroughly using a plate shaker.
5.
Measure the absorbance at 540nm for each well.
6.
Subtract the average absorbance values of the control group (media only) from the absorbance of the experimental groups (6a. vehicle control group from the drug-treated
groups).
7.
Determine cell viability by plotting absorbance versus log compound concentration. Higher absorbance intensity values correlate to an increase in total metabolic activity from
cells.
* See: SWP titled “Handling Cytotoxic Compounds: the anti-tropomyosin compound series”
* See: SWP titled “handling cytotoxic compounds”
Describe the location: Wallace Wurth Building, Level 5, Rm 502A laboratory [tissue culture room]/ Rm 511 laboratory [plate reader measurements]
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Risk Assessment and Control Form
Date Effective: 01/01/2007
Uncontrolled document when printed
Current Version: 2.6, 16/07/2008
Step 2: Identify who may be at risk by the activity
A number of people may be at risk from any activity. This may affect the risk controls needed. These people may include fellow workers, visitors, contractors and the public. The
location of the activity may affect the number of people at risk.
Experimental operator: Staff member, student
Other laboratory staff/students
Visitor/contractor
Steps 3 to 7: Identify the hazards, risks, and rate the risks
1. An activity may be divided into tasks. For each task identify the hazards and associated risks.
2. List existing risk controls and determine a risk rating using the UNSW Risk Rating Procedure.
3. Additional risk controls may be required to achieve an acceptable level of risk. Re-rate the risk if additional risk controls used.
Tasks
Hazards
Associated risks
(Step 3)
(Step 4)
Risk rating with existing
controls *
Additional risk
controls required
Risk Rating with
additional controls *
(Step 5)
(Step 6)
(Step 7)
Existing risk controls
C
L
R
(Apply the
hierarchy of risk
controls)
Prepare MTT stock
concentration of 2mg/ml
from powder in PBS
MTT powder
Ingestion,
inhalation, skin or
eye contact
Personal protective
equipment used.
3
D
M
Not required
Plate mammalian cells at
the required density in a
96 well plate.
Mammalian cells
Infection
Personal protective
equipment used.
1
E
L
Not required
Treat cells with cytotoxic
compound of interest
REFER TO RISK
ASSESSMENT ON
HANDLING CYTOTOXIC
COMPOUNDS
-
-
-
Add 50μl MTT stock
solution directly to the cells
in culture medium
MTT stock solution
3
D
M
As above
Personal protective
equipment used.
C
L
R
Not required
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Risk Assessment and Control Form
Date Effective: 01/01/2007
Uncontrolled document when printed
Current Version: 2.6, 16/07/2008
DMSO
Ingestion, vapor
inhalation, skin or
eye contact
Add 100μl DMSO to each
well
* C = consequence
L = likelihood
Decanting performed in
fume hood.
3
D
M
Not required
Personal protective
equipment used
R = risk rating
from the UNSW Risk Rating Procedure
Step 8 Documentation and supervisor approval
Completed by: Teresa Bonello
(signature)
Authorised by: Peter Gunning
(signature)
Date: Jun09
Step 9: Implement the additional risk controls
identified
Indicate briefly what additional risk controls from Step 6 above were implemented, when and by whom.
Risk control:
Date:
Implemented by:
Risk control:
Date:
Implemented by:
Step 10: Monitor and review the risk controls
It is important to monitor risk controls and review risk assessments regularly. Review is required when there is a change in the process, relevant legal changes, and where a cause for concern has
arisen. Reviews could be scheduled on an annual basis. If the risk assessment has substantially changed a new risk assessment is warranted.
Review date:
Reviewed by:
Authorised by:
Review date:
Reviewed by:
Authorised by:
Review date:
Reviewed by:
Authorised by:
Documentation
It is a requirement that legal and advisory documentation that supports this risk assessment be listed. Such documentation includes Acts, Regulations, Australian Standards and Codes of Practice,
where applicable.








NSW OHS Act 2000
NSW OHS Regulation 2001
Safe Work Procedure Form (OHS026)
Australia Dangerous Goods Code.
AS/NZS 2243.2:2006. Safety in laboratories. Part 2: Chemical aspects
Australian Standard AS2243.3-2002. Safety in laboratories. Part 3: Microbiological aspects and containment facilities.
AS/NZS 2161.1:2000 Occupational Protective Gloves – Selection, Use and Maintenance
AS/NZS 1336:1997 Recommended Practices for Occupational Eye Protection
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Risk Assessment and Control Form
Date Effective: 01/01/2007
Uncontrolled document when printed
Current Version: 2.6, 16/07/2008
UNSW Concise OHS Risk Rating Table
OHS697
What you need to do
1. Consider what can go wrong that can hurt someone
2. Determine what the most likely outcome would be - Consequences
3. Determine how likely those consequences are - Likelihood
4. Calculate the risk rating
5. Required action
How severely could someone be hurt
death or permanent disability to one or more persons
hospital admission required
medical treatment required
first aid required
injuries not requiring first aid
CONSEQUENCES:
Severe
Major
Moderate
Minor
Insignificant
How likely are those consequences?
expected to occur in most circumstances
will probably occur in most circumstances
could occur at some time
is not likely to occur in normal circumstances
may occur only in exceptional circumstances
LIKELIHOOD:
Almost certain
Likely
Possible
Unlikely
Rare
CONSEQUENCES
Insignificant
1
Minor
2
Moderate
3
Major
4
Severe
5
M
H
H
VH
VH
M
M
H
H
VH
Possible
C
L
M
H
H
VH
Unlikely
D
L
L
M
M
H
Rare
E
L
L
M
M
M
LIKELIHOOD
Almost
certain
A
Likely
B
Risk level
Very high
High
Medium
Low
Required action
Act immediately:
The proposed task or process activity must not proceed. Steps must be taken to lower the risk level to as
low as reasonably practicable using the hierarchy of risk controls.
Act today:
The proposed activity can only proceed, provided that:
(i) the risk level has been reduced to as low as reasonably practicable using the hierarchy of
risk controls;
(ii) the risk controls must include those identified in legislation, Australian Standards, Codes of
Practice etc.
(iii) the risk assessment has been reviewed and approved by the Supervisor and
(iv) a Safe Working Procedure or Safe Work Method has been prepared.
(v) The supervisor must review and document the effectiveness of the implemented risk
controls.
Act this week:
The proposed task or process can proceed, provided that:
(i) the risk level has been reduced to as low as reasonably practicable using the hierarchy of
risk controls;
(ii) the risk assessment has been reviewed and approved by the Supervisor and
(iii) a Safe Working Procedure or Safe Work Method has been prepared.
Act this month:
Managed by local documented routine procedures which must include application of the hierarchy of
controls.
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Page 4 of 4
UNSW Concise OHS Risk Rating Table
Effective date: 01/01/2007
Uncontrolled document when printed
Current Version: 2.6,16/07/2008