blue
building
chemical
chemistry
chimney
construction
electric
energy
engineering
environment
environmental
factory
fuel
gas
gasoline
global
hand
heavy
hold
industrial
industry
landscape
light
manufacturing
metal
night
oil
petrochemical
petroleum
pipe
pipeline
plant
pollute
pollution
power
present
production
refine
refinery
sky
smoke
station
steam
steel
storage
structure
tank
technology
tower
warming