Search the Properties of Matter site Properties of Matter glossary Photos, illustrations and streaming media on the Properties of Matter site Properties of Matter table of contents Properties of Matter home page Link to NSRC home page

Reading Selection, Lessson 6

The Properties of Asbestos: The Pros and Cons

Click here for audio and Spanish translation
piece of asbestos rock, with penny in foreground for scale
This is a piece of asbestos rock. Can you see the fibers?

Many substances burn when they are heated. Others melt or evaporate. Some substances, such as asbestos, do not change when they are heated. This property can be very useful. For centuries, people have known that this fibrous mineral has many useful properties. It is fire resistant. It does not melt or react with air, at least not until it gets very hot. One form of the mineral withstands temperatures up to 2750 °C. It is a very good insulator. It is strong. It resists acid. It is chemically inactive. It can be woven into cloth. Asbestos has some very useful properties, and it is readily available at a low cost.

The Romans used asbestos for lamp wicks. Egyptians used it to make burial cloths. In modern times, asbestos has been used in roofing and flooring, electrical and heat insulation, and brake linings. Because of its fire-resistant properties, asbestos has been used for a wide variety of other purposes, from theater curtains to firefighters' suits and gloves.

Two firefighters wearing asbestos suits.
These firefighters are wearing suits woven from asbestos to protect them from the intense heat produced by a fire.

Until the 1970s, asbestos was widely used and asbestos mining and production were important industrial activities in the United States. Today, asbestos mining is banned in this country, and the use of asbestos has been strictly regulated.

Why? It is now known that inhaling asbestos fibers can cause lung disease. Asbestos releases tiny particles that remain suspended in the air. Once inhaled, these downy particles can remain in the lungs for decades. They cause delicate lung tissue to stiffen. A lung disease, called asbestosis, and a type of cancer may occur years after the original exposure.

Today, construction companies are not allowed to use asbestos as insulation or fireproofing in new buildings. Workers who are exposed to asbestos must wear protective clothing. They have to shower and change clothes before going home.

Government regulations also apply to some buildings that had already been built when the new laws were passed. For example, schools that contain asbestos products have had to remove them.

Asbestos fiber under a microscope
Asbestos fibers as seen through a microscope

So, there's good news and bad news. Regulating the mining, manufacture, and use of asbestos has reduced the health risk that millions of Americans were being exposed to daily. But nothing has yet been found that can replace asbestos. However, researchers are exploring the use of synthetic fibers, fiberglass, and plastics as asbestos substitutes.

It's a trade-off: using a substance that has many useful properties versus having a safer environment. In the United States, the decision has been made. What other similar trade-offs can you think of?

Asbestos fiber in human lung tissue
Asbestos fibers in the human lung can cause several diseases, some fatal.

QUESTION

Many substances with useful properties have some undesirable ones as well. (Although the amount of the substance involved is an important factor.) Use library and Internet resources to answer the following question: What are some properties and some of the pros and cons of using one of the following substances: mercury, plutonium, or benzene?

Information about the STC/MS curriculum Link to NSRC home page NSRC contact information NSRC copyright and permissions information Smithsonian Institution privacy policy Properties of Matter site map