blue

building

business

chemical

chemistry

chimney

construction

crude

distillation

distillery

ecology

energy

engineering

environment

environmental

equipment

factory

fossil

fuel

gas

gasoline

industrial

industry

manufacturing

metal

natural

oil

petrochemical

petrol

petroleum

pipe

pipeline

plant

pollution

power

processing

production

refinery

silver

sky

smoke

station

steam

steel

storage

structure

tank

technology

valve

white