advice
advisory
alert
arrow
attention
background
beware
caution
danger
dangerous
death
electric
electrical
electricity
electrocution
electroshock
energy
flash
forbidden
hazard
high
high voltage
high voltage sign
indication
industrial
industry
information
lightning
mortal
nobody
peril
pictogram
power
powerlines
powerplant
precaution
prevention
protection
risk
safety
security
shock
sign
signage
signal
signboard
substation
symbol
tension
triangle
volt
voltage
warning
warning sign
workplace
yellow