balance
crude
cycle
danger
dirt
dirty
distillation
ecology
environment
environmental
factory
flow
fuel
hazard
hydrocarbon
industrial
industry
lake
language
leak
liquid
manufacture
nature
ocean
oil
orange
petrol
petroleum
pink
plant
plumbing
polluted
pollution
power
producing
production
progress
protecting
protection
refinery
shift
ship
source
state
technology
toxic
up
water