scales

operating

petroleum

arm

scientist

fossil

gasoline

biochemistry

chemist

examining

test

expertise

solution

concentration

exploration

fuel

laboratory

manufacturing

pollution

research

uniform

engineer

gas

gloves

production

check

chemical

heavy

land

petrol

oil

control

steel

technique

worker

power

drilling

horizontal

petrochemical

mining

derrick

instrument

dirty

weighing

density

holding

lever

rig

raw

materials

sludge