The Tremolite Asbestos Registry contains people who lived in or worked in Libby, Montana, while vermiculite was mined there; these people were at risk for exposure to the tremolite asbestos that was naturally occurring in the vermiculite. ATSDR began addressing public health concerns in Libby in 1999 and created the registry in 2004. The purpose of the registry was to monitor the long-term health effects of people in Libby exposed to tremolite asbestos and to assist with communicating important health information to registrants. Researchers have used the registry to study how asbestos exposure affects human health. This research has yielded several important findings. Registry data was used to conduct the first study of the relationship between asbestos exposure and respiratory problems in children. Another study using registry data found a significant relationship between asbestos exposure and death from cardiovascular disease.