Iron rusts unless it is protected
from water with paint or some other sealant.
It is brittle unless it is combined with carbon in some amount (steel).
Processing it takes a lot of energy and can mess up the environment.
Mining it can mess up the environment.
Pure iron metal is not commonly used commercially and needs to be alloyed with carbon or other metals. This is because it reacts and rapidly corrodes specially in moist air and elevated temperatures.
by Hassan Jama Toodho