Crocidolite and its Shocking Past Use

Written by Frankie Butler, PhD Student at the Department of Earth Sciences, University of Cambridge

Crocidolite is an asbestiform riebeckite mineral, also known as blue asbestos. Asbestiform minerals, when disturbed, release microscopic fibres that can become permanently lodged in lung tissue, leading to a variety of dangerous respiratory diseases. With fine, sharp fibres, crocidolite is considered the most dangerous type of asbestos, making it all the more alarming that the mineral was once used in the manufacture of cigarettes. 

The Kent Micronite was a cigarette filter introduced by the Lorillard Tobacco Company in the 1950s. The American company marketed the filters as a medical revolution that would prevent cigarette smokers from inhaling ‘cancerous’ components of cigarette smoke. The company went so far as to claim that Micronite was safe enough to purify the air in hospital operating rooms. It is now known that 25% of the Micronite filter was crocidolite asbestos. This predated the understanding that inhalation of asbestiform minerals causes respiratory cancers such as mesothelioma.

Concerns were raised by the research department at Lorillard when they began to notice traces of mineral fibres in the smoke. Despite this, the company continued selling Kent Micronite filters for another 16 months. The cigarettes were removed from shelves in 1956, following complaints that the filter made inhalation too difficult. By this time, over 13 billion asbestos-filled cigarettes had been sold.

This sample in the Watson collection originates from Western Australia, where entire areas of previously mined land are now permanently closed to the public due to the abundance of crocidolite minerals in and around the landscape, the most famous example being the former mining town of Wittenoom, Ashburton Shire.