The Classical Elements are foundation elements for Material Universe, every object in physical realm has some configuration of these five elements viz:
Space/Aakash : most subtle and difficult to understand.
Water/Jal : more subtle than water Manu Smriti describes creation in water.
Air/Vayu : not just atmospheric air more subtle meanings/forms exist.
Fire/Agni : related with every thing that burns including acid in stomach.
Earth/Bhoomi : anything which is solid.
There are certain situations in which these elements are(said to be) contaminated, like when impure woman touches fire/water, when someone eats food(mainly associated with earth and water element) prepared by impure person etc.
Question : Is there any proof in Hindu scriptures about this contamination concept?
If I am correct fire gets contaminated for sure, because Girija(Godess Parvati Shiva's consort) cursed Agni (that he will be impure and surrounded by black smoke) at the time of Skanda/Murugan's birth, which is mentioned in Skanda Purana.