alarm
arc
beware
bomb
bright
cable
caution
construction
danger
dangerous
dynamite
electric
electrical
electricity
energy
explosive
extreme
factory
fire
flammable
flash
hazard
hazmat
high
icon
illustration
industrial
insulation
label
light
material
power
prohibition
protection
restriction
risk
safety
security
shock
sign
skill
spark
striped
substance
symbol
volt
voltage
warning
welding