alarm
alert
attention
background
barrier
building
caution
danger
dangerous
design
element
energy
entry
exclamation
frame
graphic
halt
hazardous
high
icon
illustration
information
isolated
label
labor
lines
mark
message
metal
object
pictogram
protect
protection
protective
ray
risk
safe
safety
security
sign
signal
stop
symbol
vigilance
voltage
warning
web