air
atmosphere
blue
chemical
chemistry
chimney
city
construction
crude
distillery
ecology
energy
engineer
engineering
environment
factory
fuel
gas
gasoline
global
grey
heavy
industrial
industry
manufacturing
metal
oil
petrochemical
petrol
petroleum
pipe
pipeline
pipes
plant
pollution
power
production
pump
refinery
sky
smog
smoke
steam
steel
tank
technology
tower
toxic
under
white