alarm
alert
atom
atomic
attention
background
banner
black
caution
chemical
construction
danger
dangerous
death
design
emblem
energy
flammable
hazard
hazardous
high
icon
illustration
industry
isolated
label
mark
material
nuclear
pollution
power
protection
radiation
radioactive
radioactivity
ray
risk
safety
security
set
sign
stop
symbol
toxic
triangle
uranium
warning
white
yellow