Amphibole refers to a group of dark-colored silicate minerals that is typically composed of iron and magnesium ions. Crocidolite asbestos is a fibrous amphibole that is considered to be one of the more dangerous asbestos minerals.
What are Some of the Characteristics of Crocidolite?
This form of amphibole asbestos is naturally blue to blue-gray in color. It has needle-like fibers that are the strongest of all asbestos fibers. They also have a high resistance to acids.
Flexibility is another important characteristic of crocidolite fibers. They can bend more than ninety degrees before they split in two. They have a fine texture and appear naturally in long, straight bundles. Their texture makes them easily inhalable.
Where is Crocidolite Asbestos Found?
It is most commonly found in Western Australia, Bolivia and South Africa. Crocidolite asbestos accounted for only four percent of all of the asbestos mined commercially in this country. Its limited use was a result of its lower heat resistance than some other forms of asbestos.
How was Crocidolite Asbestos Used?
Crocidolite was primarily used in products such as asbestos-containing cement. Its low heat threshold was the reason it wasn’t feasible to use it extensively as an insulator. It was also a popular component in ceiling tiles that had a low insulation factor, insulation boards that weren’t high density, and casings used to cover water, electrical, and telecommunication wires. Other commercial uses included lagging and gaskets, limpet spray and fire door insulation.
Crocidolite Asbestos had a Very Unique Commercial Use
In an article titled “Crocidolite Asbestos Fibers in Smoke from Original Kent Cigarettes”, published in the June 1, 1995 edition of Cancer Research, the level of crocidolite asbestos used in Kent Micronite cigarette filters between 1952 to mid-1956 is discussed.
The researchers removed a filter from one of these cigarettes and ashed it in a muffle furnace at a temperature ranging between 450-500 degrees Celsius overnight. The weight of the residue was determined to be the amount of asbestos contained in the filter, which was found to be 10 milligrams.
Crocidolite fibers were present in the smoke from the first two puffs of each cigarette smoked. The researchers concluded that at the rate at which asbestos was released, a person smoking a pack of these cigarettes daily would have ingested more than 131 million crocidolite fibers longer than 5 micrometers in one year. This led them to conclude that, “people who smoked the original version of this cigarette should be warned of their possible substantial exposure to crocidolite during the 1950s.”
An interesting side note to this research is how it came about. The P. Lorillard Company that manufactured Kent cigarettes claimed that the Micronite filter was healthier for smokers. However, when a significant number of employees who made these filters began developing respiratory diseases, it signaled the need for investigation. That is when the scientists who authored the study described above found an unopened pack of Kent cigarettes with cellophane intact, marked with a Pennsylvania tax stamp, which had been manufactured around 1955, and conducted their research.