Transcript RADIATION SAFETY TRAINING

RADIATION
SAFETY
TRAINING
Presented by:
Ali Shoushtarian
Office of Risk Management, Environmental Health and Safety Service
Last revised Jan. 2009
Manager, Radiation and Biosafety
Lois Sowden-Plunkett
ext. 3058
[email protected]
Compliance Inspector
Ali Shoushtarian
ext. 3057
[email protected]
Radiation Safety Program Web Page http://www.uottawa.ca/services/ehss/ionizing.htm
REGULATORY AGENCIES
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Canadian Nuclear Safety Commission (CNSC)
City of Ottawa
Ontario Fire Marshall
Transport Canada
Ontario Ministry of Labour
STAKEHOLDERS
Radiation Safety Committee
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Reports to the Board of Governors
Chaired by Vice-Rector, Research
Ensures compliance with CNSC regulations
and license conditions, issues permits
Office of Risk Management – EHS
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Manages the radiation safety program
Conducts inspections
Monitors doses, inventory
Conducts training
STAKEHOLDERS
Radioisotope Permit Holder
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Ensures all University regulations, policies and requirements are met
Adheres to all permit limits and conditions
Ensures a safe work environment
Radioisotope User
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Complies with all elements of radiation safety program
Works in a safe fashion (self, colleagues, environment)
attends all appropriate training
PERMITS
1.
2.
3.
4.
Open Sources
Sealed Sources
Sealed Sources incorporated in a device
Exempt Quantities
with associated permit conditions
COURSE OUTLINE
GENERAL INTRODUCTION
physical and biological characteristics
risk analysis
units and calculations
OPERATIONAL PROCEDURES
ordering and receipt of material
inventory and disposal
monitoring
SAFE PRACTICES
personal protection
handling procedures
laboratory safety
MOVIE
WHAT
WHATIS
ISRADIATION
RADIATION??
RADIATION
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Spontaneous decay
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Half-life
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4 geometry
RADIATION
Excess p & n  alpha particles
Excess p  positron ( + )
Excess n  negatron (  - )
Excess nuclear E  gamma ray
Excess orbital E  X-ray
ALPHA EMISSION
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origin: DISINTEGRATING NUCLEUS (Mainly heavy nuclei)
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form of radiation:
PARTICLE
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energy range:
4-8 MeV
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range of travel:
2-8 cm in air
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other characteristics:
LARGE MASS, DOUBLE CHARGE,
HIGH SPECIFIC ACTIVITY
BETA EMISSION
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origin:
DISINTEGRATING NUCLEUS
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form of radiation:
NEGATRON (electron)
POSITRON (similar to an electron but
positive charge)
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energy range:
0.02 - 4.8 MeV
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range of travel:
0 - 10 m in air
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other characteristics: DIFFERS FROM AN ELECTON IN ORIGIN AND ENERGY; TRAVELS
ALMOST THE SPEED OF LIGHT; ALMOST NO MASS (9.1x 10-31 kg)
GAMMA EMISSION
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origin:
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form of radiation:
ELECTROMAGNETIC RADIATION
(emr - photon)
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energy range:
10 keV - 3 MeV
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range of travel:
100 m in air
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other characteristics: ZERO MASS, ELECTRICALLY NEUTRAL
NUCLEUS
X-RAY EMISSION
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origin: ORBITAL ELECTRON
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form of radiation:
ELECTROMAGNETIC RADIATION
(emr - photon)
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energy range:
10eV - 120 keV
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range of travel:
100 m in air
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other characteristics: ZERO MASS, ELECTRICALLY NEUTRAL
INTERACTION WITH MATTER
IONIZATION
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Electron is removed from an electron shell leaving a charged particle.
EXCITATION
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Electron is raised to a higher energy level but isn’t knocked out of the shell
INTERACTION WITH MATTER
BREMSSTRAHLUNG
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A negatron approaches the nucleus and is accelerated.
As it leaves the nucleus it decelerates and emits excess energy as emr.
INTERACTION WITH BIOLOGICAL
MATTER
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DIRECT
vital cell structures
INDIRECT
• ionizes H2O
• forms peroxides
• interacts with the vital cell structure
RADIATION RANGES IN TISSUE
(average linear dimension of a cell = 17.1 m )
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alpha particles of 210Po ……… 15m
beta particles of 3H …………… 5 m
beta particles of 32P ……….. 300 m
gamma rays of 60Co …………. infinity
RADIOSENSITIVITY OF CELLS
• Blood producing and reproductive cells are the most sensitive
• Muscle, nerve and bone cells are the least.
At low doses, the effects of radiation are not known.
INTERNAL DOSES
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CRITICAL ORGANS
 3H – Body water or tissue
 14C – Fat tissue
 32P – Bones
 35S – Gonads
 125I – Thyroid
 57Co – Large Intestine
PREGNANCY
EXTERNAL DOSES
Gamma rays
Beta particles
Alpha particles
BIOLOGICAL RESPONSE TO
RADIATION
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No change
Mutation and repair
Permanent change with limited effect
Changes leading to cancer or other effects
Death of cell / organism (minutes - years)
THE EFFECTS OF RADIATION ON THE
HUMAN BODY
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Genetic
» appears in latter generations
» due to cell damage of the reproductive organs
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Somatic
» appears in the irradiated individual
» immediate or delayed effects
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Stochastic
» refers to probability of biological effect due to ionizing
radiation
» assumes effect is proportional to dose / dose rate, i.e.,
no safe threshold
THERMOLUMINESCENT DOSIMETRY
Dose Limits:
Whole body, gonads,
bone marrow
Skin, thyroid, bone
Tissue of hands, feet,
and forearms
non-NEW
1 mSv
50 mSv
50 mSv
NEW
50 mSv
500 mSv
500 mSv
COMPARISON OF RISK
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exposure to 100 Sv ionizing radiation
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smoking 1.5 cigarettes
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travelling 50 miles by car
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being male and 60 years old for 20 minutes
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canoeing for 6 minutes
UNITS OF RADIATION
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ACTIVITY
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ABSORBED DOSE
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DOSE EQUIVALENT
ACTIVITY UNITS
Non - S.I. (Système international)
CURIE (Ci)
1 Ci = 3.7 x 1010 dps
S.I.
BECQUEREL (Bq)
1 Bq = 1 dps
ABSORBED DOSE UNITS
Non - S.I.
RAD (rad)
1 rad = 100 ergs of energy/g
S.I.
GRAY (Gy)
1 Gy = 1 joule of energy/kg
DOSE EQUIVALENT UNITS
Non - S.I.
REM (rem)
1 rem = rad x Quality Factor
S.I.
SIEVERT (Sv)
1 Sv = Gy x Quality Factor
CALCULATIONS
TWO IMPORTANT CALCULATIONS:
1. Decay correction
2. Converting cpm to Curies
CALCULATIONS
1. DECAY CORRECTION
A
Ao
t

A = Aoe -  t
= activity at time “t”
= activity at time zero
= elapsed time
= decay constant ( = 0.693 / t 1/2)
CALCULATIONS
Example:
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250 Ci of 35S arrived on May 19, 2005
100 Ci was removed and used the same day.
The remaining amount was stored in a freezer for future use.
On June 30, 2005, it is decided to repeat the experiment.
? Does another order of
35S
have to be placed or is there enough remaining activity that the
experiment may proceed?
CALCULATIONS
Solution:
A
= A0e - t
A
= activity at time ‘t’ ( ? )
A0 = activity at time zero (250 - 100 = 150 Ci)
t
= elapsed time (42 days)

= decay constant (0.693 / 87 days = 0.00797 )
A = (150)e - (0.00797)(42)
A = 107.32 Ci
(** SAVINGS **)
CALCULATIONS
2. CONVERTING CPM TO CURIES
Step 1 Determine counting
efficiency of the detector.
Step 2 Convert cpm to dpm.
Step 3 Convert dpm to Curie.
CALCULATIONS
Step 1 Determine counting efficiency of the detector
source with a known activity.
using a
% efficiency = observed cpm - background cpm x 100 source of emission rate (dpm)
Ex.
count rate
= 2045 cpm
background = 65 cpm
source
= 220 Bq = 1.32 x 104 dpm
% efficiency
= 2045 - 65 cpm
=
15%
1.32 x 104 dpm
CALCULATIONS
Step 2 Convert cpm to dpm.
dpm = corrected cpm
efficiency
Ex. Sample
= 4925 cpm
background = 65 cpm
efficiency
= 15%
dpm = 4925 - 65 = 32,400
0.15
CALCULATIONS
Step 3 Convert dpm to curie.
1 Bq = 1 dps = 2.7 x 10-11 Ci
60 dpm = 2.7 x 10-11 Ci
Since
Then
Therefore
32,400 dpm = 1.48 x 10-8 Ci
or, # Bq = __1.48 x 10-8 Ci_ = 540 Bq
2.7 x 10 -11 Ci/Bq
CLASSIFICATION OF LABORATORY
Annual Limit on Intake (ALI)
The activity, in Becquerel (Bq), of a radionuclide that will deliver an effective dose of 20 mSv after the radionuclide is taken into the body
Basic: 5 X ALI
Intermediate: 5-50 X ALI
High: 50-500 X ALI
Exemption Quantity (EQ)
The quantity, in Becquerel (Bq), of a radionuclide, below which no licence is required
10000 EQ: Written approval from CNSC
CLASSIFICATION OF RADIONUCLIDES
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Contamination levels
Decommissioning levels
Class A (high): Na-22, Zn-65
Class B (med): Rb-86
Class C (low): H-3, C-14 , S-35, Ca-45,
P-33, P-32, I-125
DECAY PRODUCTS
32P
 Sulphur
14C
 Nitrogen
35S
 Chlorine
3H
 Helium-3
OPERATIONAL PROCEDURES
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Ordering
Receipt of Radioactive Material (TDG)
Inventory
Disposal
Monitoring
Inspection of Laboratories
ORDERING
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Radioactive materials purchase procedures
- Radioisotopes Purchase Requisition form
- Form must be complete (PO number, signature)
- EHSS approval before ordering
- Documentation (packing slips, shipper’s declaration)
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Permit conditions
Material purchased for other labs
Inventory records
PURCHASE
REQUISITION
FORM
RECEIPT OF RADIOACTIVE MATERIAL
• TDG – Class 7
- Definition of radioactive materials
- Radioactive packages
- Radiation warning labels
- Receipt of radioactive material
TDG – CLASS 7
DEFINITION OF RADIOACTIVE MATERIAL FOR TRANSPORT
Former:
- 70kBq/kg
New:
- radionuclide dependent
- types of radiation
- energies
- chemical forms
- potential biological effect on persons
TDG – CLASS 7
Radioactive packages may be shipped as:
- Excepted packages
- Industrial packages – Categories I, II and III
- Type A packages – lower amounts
- Type B (U) packages – large amounts; ≤ 700 kPa
- Type B (M) packages – large amounts; > 700 kPa
- Type C packages – for air transport of high activity
TDG – CLASS 7
EXCEPTED PACKAGES
- The safety mark ‘RADIOACTIVE’ must be visible on
opening the package
- The radiation level at any point on the external surface
of the package must not exceed 5 Sv/h
All other packages must be categorized by radiation
level and display the corresponding radiation warning
labels as follows:
TDG – CLASS 7
RADIATION WARNING LABELS
Category I-White:
less than 5 Sv/h
Category II-Yellow:
less than 500 Sv/h, TI less than 1
Category III-Yellow:
less than 2 mSv/h, TI less than 10
TI: maximum radiation level in Sv/h at 1 meter from the
external surface of the package, divided by 10.
Ex: 1 Sv/h (0.1 mrem/h) at 1 m equals a TI = 0.1
TDG – CLASS 7
RECEIPT OF RADIOACTIVE MATERIAL
- Radioactive packages must be delivered to the laboratory using a cart
to increase distance between the transporter and the package in order
to minimize radiation exposure
- Inspect packaging both externally and internally for damage or leakage
- Perform contamination monitoring on the package, vial holder and vial
- Deface wording and labels prior to disposal of the package
- Complete an Inventory of Use and Disposition form
Report any anomalies to the supervisor and RSO
INVENTORY
• Sealed Sources
(encapsulated, incorporated in a
device, check sources)
• Open Sources
• Transfers
** HISTORICAL
INVENTORY
DISPOSAL
Radioactive
Waste
Solid
Waste
Water-Soluble
Waste
Liquid Scintillation
Waste
Animal Carcasses
Waste
DISPOSAL
Solid Waste
Landfill
Short-Term Storage
Off-Site
(1 DL / kg)
(t 1/2 = 90 days)
Disposal
(1 DL/kg)
(e.g., sealed sources)
DISPOSAL LIMITS (DL) TO MUNICIPAL GARBAGE
C-14: 3.7 MBq (100 μCi)/kg; H-3: 37 MBq (1000 μ Ci)/kg
I-125: 0.037 MBq (1 μ Ci)/kg; P-32: 0.37 MBq (10 μ Ci)/kg
DISPOSAL
Labels
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On decay can
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Deface contents
DISPOSAL
DISPOSAL
Time required for decay
A = Ao e -  t
t = ln (A/Ao)
-
A
= activity at time ‘t’
Ao
= activity at time zero
t
= elapsed time
 = decay constant (  = 0.693 / t 1/2 )
DISPOSAL
Example:
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100 μCi of 32P solid waste collected
Weight of waste = 0.785 kg
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Disposal limit of 32P is 0.37 MBq/kg (10 μ Ci)
half life (t1/2) of 32P is 14.3 days
DISPOSAL
Solution:
Step 1
Determine activity (A) permitted at disposal
Weight = 0.785 kg
1 DL/kg = 10 Ci / kg
A = Weight X 1 DL / kg
A = 0.785 kg X 10 Ci / kg
A = 7.85 Ci
DISPOSAL
Step 2: Determine Length of Decay Period (t)
t = ln (A/Ao)
-
A
= activity at time ‘t’ (7.85 Ci)
Ao = activity at time zero (100 Ci)
t
= elapsed time (?)

= decay constant (0.693 / 14.3 days = 0.0485/day)
t =
ln (7.85 Ci / 100 Ci) = 52.5 days
- 0.0485/day
DISPOSAL
Water Soluble
Waste
DL/Year/Building
C-14: 0.01 TBq, H-3: 1 TBq
I-125: 100 MBq, P-32: 4 GBq
DISPOSAL
Liquid Scintillation
Waste
Off-Site Disposal
DISPOSAL
DISPOSAL
A n im a l C a rc a s s es
W a s te
B io m ed ical W aste
(O ff-S ite
D is p o s a l)
R a d io a c tiv e W a s te
(O ff-S ite
D is p o s a l)
MONITORING
Survey Meters
versus
Contamination Monitors
MONITORING
• Leak testing
• Contamination monitoring
• Dose rate around storage, waste, use areas
* prior to repair of equipment
MONITORING
Leak Testing (Sealed Sources)
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Sources  1.35 mCi
frequency [6 (in use), 12 (in a device), or 24 months (storage)],
CNSC procedures,
certificates
reporting criteria (200 Bq leakage)
transfers, incidents (immediately)
MONITORING
Contamination Monitoring (Open Sources)
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Map of lab
Weekly or after 5 x ALI
Decontaminate
Record “no radioisotope used”
After any spill
MONITORING
Contamination
Criteria <
Class A: 3.0 Bq/cm2
Class B: 30 Bq/cm2
Class C: 300 Bq/cm2
Decommissioning
Criteria <
Class A: 0.3 Bq/cm2
Class B: 3.0 Bq/cm2
Class C: 30 Bq/cm2
EHSS Criteria
0.3 Bq/cm2
Contamination Monitoring
Parameters of interest for contamination monitors-Efficiency
Detector Covering
Efficiency:
1) Distance: 1/r2
2) Beta Absorption
3) Size of window
Detector Volume
Surface
Not all decay emissions
Are detected!
Contamination Monitoring
Converting cpm results into Bq/cm2 for GM pancake
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Bq/cm2 = (Cpm – Bkg) / Ec X Ew X 60 X A
where Cpm = counts per minute for the wipe,
Bkg = counts per minute of the background filter,
Ec = scintillation counter efficiency (see note below), or GM efficiency
Ew = wipe efficiency, assume 10% (0.1), and
A = area wiped in cm2.
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Note: As a rule of thumb, when the counter efficiency (Ec) is unknown,
the following
efficiencies can be used for the purpose of counting wipes:
100% (1) for 32P, 14C, 35S
75% (0.75) for 125I
50% (0.5) for 3H and unknowns
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INSPECTIONS
1.
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4.
5.
General Condition of lab
Inventory/Disposal
Contamination Monitoring
Measurements
Questionnaire
Dose rate measurements should be
undertaken:
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Routinely to ensure doses are ALARA
Around storage, waste and use areas
Whenever new sources arrive, or new radioisotopes are used
When new experimental procedures are implemented
SAFE HANDLING PRACTICES
A
L
A
R
A
As
Low
As
Reasonably
Achievable
SAFE HANDLING PRACTICES
TIME
D=dXt
D = radiation dose
d = radiation dose rate
t = time duration of exposure
SAFE HANDLING PRACTICES
DISTANCE
D1 = dose at distance 1
s1 = distance 1
D2 = dose at distance 2
s 2 = distance 2
Inverse Square Law
D1 s12 = D2 s22
SAFE HANDLING PRACTICES
SHEILDING
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reduces or stops radiation
• dependent on:
- energy of radiation
- type of shielding
remember: 4 geometry
PERSONAL PROTECTION EQUIPMENT
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LAB COAT
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GLOVES
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SAFETY GLASSES
SPILL RESPONSE
1. REPORTING
2. CLEAN-UP
3. LEAVING CONTAMINATED AREA
4. PERSONAL DECONTAMINATION
SPILL RESPONSE
1.
REPORTING
 Inform co-workers & supervisor.
 Inform Protection Services (5411)
 Inform ORM
(3058, 3057)
SPILL RESPONSE
2.
CLEAN-UP
1. Attend to injured person and ensure personal safety.
2. Assess the size of the spill.
3. Obtain necessary supplies.
4. Cover spill with absorbent.
SPILL RESPONSE
5. Push spill towards centre.
6. Decontaminate area in sections.
7. Check for contamination (record).
8. Re-clean as necessary.
9. Inform Radiation Safety Officer of fixed contamination.
SPILL RESPONSE
3.
LEAVING A CONTAMINATED AREA
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Monitor self (especially feet, hands and lab coat).
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Leave lab coat behind if contaminated and remove
dosimeter badge.
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Put up sign and lock door.
SPILL RESPONSE
DO NOT ENTER!
Name
Telephone #
Nature of Spill
Location
Time of Return
SPILL RESPONSE
4.
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PERSONAL DECONTAMINATION
Use tepid water and mild soap.
Avoid causing abrasions to skin.
Wash for a few minutes, dry and monitor. (fingernails too!)
Carefully monitoring is the only way to measure progress.
Suspicious packages
Unopened
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Do not open and do not shake
Place in secondary container or cover
Inform others of the situation
Clear the room and section off the area
All individuals who may have come into contact with the material
must wash their hands
 Call Protection Services and wait for their arrival
 List all the individuals present in the room or area when the package
arrived. Give this list to Protection Services for follow-up
Suspicious packages
Opened
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Contents Intact
Do not manipulate contents further
Cover the package
Inform others of the situation
Clear the room and section off the area
All individuals who may have come into contact with the material
must wash their hands
• Call Protection Services and wait for their arrival
• List all the individuals present in the room or area when the package
arrived. Give this list to Protection Services for follow-up
Suspicious packages
Contents not intact (spilled)
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Do not try to clean up the spill
Gently cover the spill
Inform others of the situation
All individuals who may have come into contact with the material
must wash their hands
• Call Protection Services
• Remove heavily contaminated clothing (place in bag) and shower
using soap and water
• List all the individuals present in the room or area when the package
arrived. Give this list to Protection Services for follow-up
SUMMARY
External Dose:
time
distance
shielding
Internal Dose:
critical organs
prevent: …. ingestion
…….absorption
…….inhalation
THINK SAFETY
PLAN
PRACTICE
REVIEW