access
area
asphyxiate
asphyxiation
asthma
atmospheric
avoid
background
breathing
carbon
carcinogen
chemical
confined
danger
do
dust
enter
entry
environment
gas
hazard
health
icon
illustration
industrial
label
lung
mask
not
permit
poison
pollution
protection
protective
required
respirator
restricted
risk
safety
shield
sign
space
sticker
suffocation
symbol
tag
template
toxic
zone