app
art
atom
atomic
attention
background
badge
biological
blue
button
caution
chemical
chemistry
concept
danger
dark
design
document
ecology
energy
file
flat
graphic
hazard
icon
illustration
information
isolated
label
mark
medical
nuclear
pollution
power
radiation
radioactive
radioactivity
report
science
seal
shape
sign
silver
stamp
symbol
test
token
toxic
warning