This document summarizes various radiation hazards. It describes the characteristics and effects of different types of radiation including ultraviolet, visible, infrared, radiofrequency/microwave, lasers, ionizing radiation, and provides safety precautions for each. Specifically, it notes that UV radiation can cause eye damage and skin cancer, lasers require special precautions due to their intensity, and ionizing radiation can damage tissues and DNA leading to cell death or mutation and potentially cancer if exposure limits are exceeded.

1. RADIATION HAZARDS

2. Important characteristics of
radiation
• Wavelength
• Frequency
• Intensity
• Velocity
• Straight line propagation
• Spectrum
• Inverse square law

3. Ultraviolet radiation hazards
• Common sources: sun, UV lamps (‘black lights’),
welder’s arc
• Some devices may emit only a small amount of
visible light while emitting intense UV radiation
• Especially dangerous to the eyes since they do not
dilate readily in response to UV -- retinal burns
• Photosensitization to UV can occur from certain
dermal chemicals and oral drugs (e.g. antibiotics)

4. Types of UV Radiation
Type Wavelength Effect
UV-A
“Black light” Region
315-400 nm Little effect
UV-B 280-315 nm Skin cancer
possible
UV-C 100-280 nm Cornea damage

5. Visible radiation hazards
• Common sources: sun, all visible lamps
• Major damage likely only if intense beam is
focused on the retina
• Eye usually registers pain before serious
damage occurs

6. Infrared Hazards
• Major effect is burns
• Eye is not very sensitive so can be damaged
if IR is intense
• Skin burns possible but usually avoided
due to pain from heat before serious injury
occurs

7. Radio-frequency and Microwave
Hazards
• Sources include analytical instruments (e.g.
NMR), cathode ray tubes (including oscilloscopes,
TVs, and computer monitors), microwave ovens,
and communications devices (e.g. cell phones)
• Biological effects to man uncertain
• Suggestion of sterility problems, birth defects and
cataracts from microwaves
• Pacemakers are effected by microwaves

8. LASER HAZARDS
• LASER = Light Amplified by Stimulated
Emission of Radiation
• Especially hazardous due to very narrow
beam which can be very intense
• Lens of eye may concentrate energy onto
retina by another 100,000 times

9. LASER HAZARDS (cont’d)
• Use minimum power laser possible for job
• Keep laser beam off or blocked when not in use
• Post warning signs when lasers are in use
• Never look directly at a laser beam or align it by
sighting over it
• If possible, use laser in lighted room so that pupils
will be constricted
• Do not depend on sunglasses for shielding.
• Make sure any goggles used are for the
wavelength of the laser used and are of adequate
optical density

10. Ionizing Radiation
Characteristics
Mass Charge Stopped by
Alpha 4 +2 4 cm air
Beta 0 -1 6-300 cm
air
Lowered
10% by
X-ray 0 0 15-30 cm
tissue
Gamma 0 0 50 cm

11. Ionizing Radiation Units
• Curie (Ci) = 37 billion disintegrations/sec
• Roentgen (R) = energy which will produce
1 billion ion pairs/mL air
• Rad = 100 ergs absorbed energy/gm
• Rem = absorbed dose in rads multiplied by
factor related to type of radiation (1 for
beta, gamma, X-ray; 20 for alpha)

12. Ionizing radiation damage
• Tissue burns, minor and/or destructive
• DNA breaks leading to cell death or
mutation, potentially cancer

13. Human radiation dose-effect data
DOSE (rems) PROBABLE EFFECT
0-25 No noticeable effect
25-100 Slight blood changes
100-200 Vomiting, fatigue
(recovery in weeks)
200-600 Vomiting, severe blood
changes, hemmorhage
(recovery in 1-12 mo.)
600-1000 Survival unlikely

14. Regulatory mandates
on ionizing radiation
• Nuclear Regulatory Commission
occupational standard (10 CFR 20) is 5
rems/yr for whole body radiation. [Note
that a lifetime exposure to 5 rem total is
thought to shorten life by 1-3 weeks.]
• Standard for nonwork environment is 170
mrem/yr.

15. Ionizing radiation
General precautions
• Confine radioactive chemicals to small areas
which are posted
• Cover bench tops with plastic-backed absorbent
material
• Use trays to catch spills
• Wear gloves to protect hands and lab coat to catch
splatters
• Dispose of contaminated clothes appropriately

16. Radiation monitoring devices
• Film badges – after the fact measurement,
developed weekly or monthly
• Geiger counter – best for high energy beta,
gamma
• Scintillation counter – used for wipe
surveys