Discover STEM - Petrosains, The Discovery Centre

Could The PETRONAS Twin Towers Become Rusty?

We often hear that environmental pollution can give harmful effects on humans or animals, but did you know that it can also affect things around us such as buildings?


Some buildings will change colour or get rusty over time. For example, any time the paint on your fence is chipped to expose the iron underneath, rust is likely to develop in that spot.

Weather, rainstorms and high humidity can both cause rust. Wrought iron fences are more likely to rust especially in highly humid areas.

Let’s get to know examples of buildings that rust over the years…

Statue of Liberty

Year 1886

The Statue of Liberty is coated in a thin layer of copper.

Year 2020

Over the years, the chemical reactions between copper and oxygen, that is surrounded by Sulphur which was present in the air turns the  original colour into blue-ish green.

Another building that is affected due to environmental issues…


Originally, Taj Mahal was made with very beautiful, pearl white marble.

The discolouration is caused by the aquatic insect that excretes on the surface of the marble, hence leaving the marble with green/ black spots.

Garbage pile-ups and sewage in the rivers increased the population of those aquatic insects, Chironomus calligraphus which will migrate to Taj Mahal and their excrement will further stain the marble.

Let’s get back to our Twin Towers..

Alloying Element

PETRONAS Twin Towers is made from stainless steel.

Stainless steel remains stainless, or does not rust, because of the interaction between its alloying elements and the environment.

Stainless steel contains iron, chromium, manganese, silicon and in many cases, significant amounts of nickel and molybdenum.

How stainless steel are protected from being rusty…

Alloy elements in stainless steel react with oxygen from water and air to form a very thin, stable film that consists of such corrosion products as metal oxides and hydroxides.

The presence of the stable film prevents additional corrosion by acting as a barrier that limits oxygen and water access to the underlying metal surface.

In addition to corrosion resistance, the advantageous physical properties of stainless steel include:

High and low temperature resistance

Malaysia enjoys tropical weather year round, thus a material with high temperature resistance is suitable for a monument.

Hygiene and ease of cleaning

Due to the fact that PETRONAS Twin Towers are located at the center of Kuala Lumpur, hence there is a lot of debris lingering in the air. So stainless steel makes it easier to clean the surface.

Aesthetic appeal

A stunning combination of stainless steel and glass finishing on the building was used to form beautiful Islamic patterns.

Therefore, we can conclude that PETRONAS Twin Towers will not get rusty over a million years!!

Do you think there are other monuments out there that has changed its colour or shape due to environmental effects?

Do find out!