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> What is Asbestos?
> What is Lead?

Asbestos is a naturally occurring mineral. It differs from other minerals in its crystal development. The crystal formation of asbestos is in the form of long thin fibers. Asbestos is divided into two mineral groups - Serpentine and Amphibole. The division between the two types of asbestos is based upon the crystalline structure. Serpentines have a sheet or layered structure where as amphiboles have a chain-like structure.

As the only member of the serpentine group, Chrysotile is the most common type of asbestos found in buildings. Also known as "white asbestos," Chrysotile makes up approximately 90 percent to 95 percent of all asbestos contained in buildings in the United States.

In the amphibole group, there are five types of asbestos. As an acronym for the Asbestos Mines of South Africa, Amosite is the second most prevalent type of asbestos found in building materials. Amosite is also known as "brown asbestos." Next, there is Crocidolite or "blue asbestos," which is an asbestos found in specialized high temperature applications. The other three types (Anthophylite, Tremolite, and Actinolite) are rare and found mainly in contaminants in other minerals. Asbestos deposits can be found throughout the world and are still mined in Australia, Canada, South Africa, and the former Soviet Union countries.

Over the years, asbestos has had many uses. Its primary use is as an insulator or fire retardant, but can also be used as a binder. Due to this versatility, asbestos can be found in may types of building materials. Even though the federal government placed a moratorium on the production of many asbestos products in the early 1970's, installation of these products continued through the late 1970's and even into the early 1980's.

Asbestos today is found in numerous building products sold throughout the United States. Under new trade agreements asbestos products are imported from Canada, Mexico, China, Russia and many other nations that still create products with asbestos. Asbestos building products being sold include drywalls, plasters, mortars, grouts, mastics, insulations, ceiling tiles, floor tiles, roofing products, etc. Once installed, most asbestos products are regulated by state and federal regulations. Due to the fact many of these products are not labeled, one of our challenges here at the University of Minnesota is to make sure asbestos containing materials are not installed in new construction.

Non-building material products that can be purchased in the United States range from crayons to brake pads and may or may not be labeled as asbestos. If you are concerned about a particular product you should contact the company that produces the product for more information.

What is Lead?

Lead is one of the first metals to have been used by humans. Its use dates back as far as 6500 BC.

Archaeological discoveries of ancient lead pipes have been discovered in Egypt dating to the time of the Pharaohs. The Roman Empire also used lead pipes and fixtures throughout their waters systems that included thousands of miles of aqueducts. These and many other early cultures have also been found to use lead in the glazes on their pottery. It is believed that poising through the food and water may have had an effect in the decline of these civilizations.

Lead is a naturally occurring element present in the earth's formation. It is usually associated with other minerals, notably zinc, silver and copper. Trace amounts of other elements, including gold are sometimes found with lead ore. The most common lead ore is galena or lead sulfide. The ore is mined, concentrated and then smelted in a blast furnace with limestone and coal. It is refined to remove and recover other metals.

Recycled lead is a significant market since lead is easily melted and molded. Lead actually is the most recycled of all industrial metals in the world. In the United States, 80 percent of lead used is in automotive-type batteries and more than 95 percent of these batteries are recycled.

Lead is important to many industries because of its natural properties:

• Mass
• Malleability
• Low Melting Point
• Corrosion Resistance
• Electrical Properties
• Long Life

Today we are seeing lead becoming essential to the production of many highly technical products such as fiber optics, microcircuits, computer monitors, TV's, Medical shielding products, etc.