Amosite asbestos, which is often referred to as "brown" asbestos is found and mined in South Africa. Amosite asbestos is generally considered to be among the more hazardous varieties of the mineral. While blue asbestos is generally considered to be the most hazardous, amosite brown asbestos is seen as the second most hazardous variety. Many S. African miners have become sick because of asbestos related disease in a country that has few regulations on asbestos mining or air quality levels.
At one time, amosite asbestos was quite prevalent in building materials and was regularly exported to the United States for inclusion in many construction compounds. Though it accounts for only 5% of known asbestos in the United States today, it was commonly used as a thermal insulation and fire retardant material in products such as floor and ceiling tiles. Today, brown asbestos is banned in most countries but can still be found in many older structures. Any fixtures containing known levels of brown asbestos should be considered highly dangerous as its use would indicate the fibers are likely to be unstable if disturbed at all. If unstable, these fibers could be extremely dangerous and released into the air for possible asbestos exposure.