There are 3 types of Asbestos that are in general use. All types are hazardous but both the Crocidolite and Amosite are known to be more dangerous.
Asbestos only becomes dangerous when fibres from the source are released and become air-borne.
These are then very easily inhaled. The above asbestos related cancers kill more people than any other work-related illness and can take anywhere from 15 to 60 years to manifest itself, making it particularly dangerous because there is no immediate change in someone's health.