Vermiculite ore is a naturally occurring fibrous mineral widely used in various consumer products, such as attic insulation, lawn and garden products, and fireproofing material. While most vermiculite ore and products do not pose a health hazard, the vermiculite mined from Libby, MT was contaminated with naturally occurring asbestos. The federal Agency for Toxic Substances and Disease Registry (ATSDR) has documented a significant number of asbestos-related deaths among Libby residents. Additionally, as part of the ongoing investigation, ATSDR has learned that this contaminated ore was shipped to hundreds of locations around the United States for processing. While the Libby mine is now closed, studies from ATSDR and elsewhere show that people who worked in the Libby mine or vermiculite processing facilities may have been exposed to hazardous levels of asbestos while the facilities were in operation. People who lived or worked near these sites also may have been exposed to asbestos if they came into contact with contaminated vermiculite. Prolonged exposure to asbestos can cause serious and life-threatening health conditions, including asbestosis, lung cancer, and mesothelioma. In response, ATSDR has initiated 10 different activities to help evaluate the potential health effects among Libby residents and populations throughout the United States who might have been exposed to the asbestos-contaminated ore found in Montana. Some of these activities include conducting environmental exposure evaluations, health statistics reviews, community screenings, and disease-specific surveillance. This article presents the various follow-up activities that have been conducted to date by ATSDR and partnering state health departments.