This is the result of the oxidisation of organic compounds in diesel and petrol fumes.
From the abcnews.go.com
They will cause oxidisation or contamination to certain types of materials.
From the en.wikipedia.org
Metals, for example, oxidise, and oxidisation produces heat,'says Furrer.
From the newscientist.com
I avoid any reusable metal filter gadgets, even with gold-plating you can taste the oxidisation.
From the guardian.co.uk
The surfactant causes chemical oxidisation which breaks toxic chemicals into less dangerous ones.
From the smh.com.au
Oxygen leads to oxidisation, bacteria growth and decay.
From the sciencedaily.com
The main advantage to bag-in-a-box packaging is that it prevents oxidisation of the wine during dispensing.
From the en.wikipedia.org
A layer of olive oil on top protects from oxidisation.
From the smh.com.au
It also has intriguing electrical qualities, because the oxidisation process turns the material from a conductor into an insulator.
From the newscientist.com
More examples
Oxidation: the process of oxidizing; the addition of oxygen to a compound with a loss of electrons; always occurs accompanied by reduction
(oxidise) enter into a combination with oxygen or become converted into an oxide; "This metal oxidizes easily"
(oxidised) oxidized: combined with or having undergone a chemical reaction with oxygen; "the oxidized form of iodine"
Redox (shorthand for reduction-oxidation reaction) reactions describe all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ...
Alternative spelling of oxidization
(Oxidise) To combining with Oxygen. Electrons are removed from an atom or a molecule (the atom becomes positively charged).
(Oxidise) is to combine a substance with oxygen. The process called oxidation results in a by-product. For example, rust is the by-product of iron oxidation. Oxidation of fish feed can lead to feed rotting.
(Oxidise) to lose electrons or gain oxygen.
(Oxidised) A chemical reaction with oxygen or where electrons are lost. See reduced.