2. Safety signs and symbols are important safety communicating
tools. They help to indicate various hazards that present in
plant site or workplace. At the same time, they warn workers to
always keep watching on those hazards by giving required
information and safety instructions.
They do not only inform the presence of hazards but also keep
workers' safety awareness. It is very important in reducing
accidents at workplace and in chemical plants.

3. To get the most out of health
and safety signs and
symbols, you should choose
the right one for each work
location in plant site. Each
work area needs different
workplace health and safety
signs and symbols. It is
because each work area has
difference type of hazard.

4. Safety Signs and Symbols Standards
Safety symbols and signs consist of messages, words and
pictorial symbol with variety of sizes, shapes and colors. All
the shapes and colors are standardized. Each shape has
different meaning and each color reflects specific meaning.
Using the standardized health and safety signs and symbols will
make them understandable and overcome language barriers.
The shapes of workplace health and safety signs are triangles,
circles and squares or rectangles.

5. a. Triangles: indicates caution (potential hazards) or warning
(definite hazards), for example toxic gas and electric shock.
b. Circles: reflects mandatory or recommended actions are
normally used to depict mandatory or recommended actions,
for example wearing eye goggles and safety hard hats.
c. Squares or rectangles: shows information, i.e. general
information and emergency information (first aid, fire
fighting).
d. Circle with a 45° diagonal slash across the middle from the
upper left to the lower right: point out forbidden or prohibited
actions.

6. The colors used in workplace safety signs and
symbols are red, yellow, blue and green.
a. Red signs: designates emergency devices like fire fighting
equipment, or to emphasize unsafe or forbidden actions.
b. Yellow: notifies workers to take caution and be alerted of
hazards, reducing necessary risks.
c. Blue: shows a particular action or behavior, for example
instruction to wear personal protective equipment.
d. Green: designates the location of emergency measures like
first aid kits, evacuation routes, fire exits, escape ladders, or
assembling point.

7. Source links:
http://www.signarama-of-canada.com/
http://ezinearticles.com/?Safety-Signs-and-Symbols---A-ShortGuide&id=5379015