Chrysotile asbestos, like all other forms of asbestos, has produced tumors in animals. Mesotheliomas have been observed in people who were occupationally exposed to chrysotile, family members of the occupationally exposed, and residents who lived close to asbestos factories and mines. Amosite and crocidolite are the most hazardous of the asbestos minerals because of their long persistence in the lungs of exposed people. Tremolite often contaminates chrysotile asbestos, thus creating an additional hazard.
Asbestos exposure becomes a health concern when high concentrations of asbestos fibers are inhaled over a long time period. People who become ill from inhaling asbestos are often those who are exposed on a day-to-day basis in a job where they worked directly with the material. As a person's exposure to fibers increases, because of being exposed to higher concentrations of fibers and/or by being exposed for a longer time, then that person's risk of disease also increases. Disease is very unlikely to result from a single, high-level exposure, or from a short period of exposure to lower levels.