It is curious to think that we can thank 30 million-year-old unicellular algae-like creatures called diatoms for the appealing appearance of such modern consumer goods as cooking oil, liquid soap, beer and wine.

Fossilized diatoms are what make up diatomaceous earth, an abundant, soft, sedimentary rock rich in biogenic silica, derived from diatom cell walls. Chemically inert and with an unusually light density, diatomaceous earth, which acts as an effective filter thanks to its intricate, microscopically small, hollow particles that trap suspended matter, was first discovered in the 1830s in Germany. Wilhelm Berkefeld, a 19th century German engineer, was the first to recognize its filtration properties and developed tubular filters that he adapted to clean drinking water.

The Berkefeld filter, as it was called, was successfully used during the 1892 cholera epidemic in Hamburg, Germany. 

This 1960 Canadian Johns-Manville Co. Ltd., advertisement in Chemistry in Canada promoted CELITE, a trademarked brand name for diatomaceous earth, for the filtration of consumer and industrial goods. Filtration, however, was a side business of the company. Founded in 1858, and called H.W. Johns Manufacturing, the American company produced roofing and insulation products. In 1926, the company was renamed Johns-Manville Corporation, becoming a significant supplier of asbestos roofing materials. As early as 1929, employees at Johns-Manville began disability claims for exposure to the carcinogenic silicate mineral. In Canada, this came to a head in 1949 when unionized francophone workers walked off the job at four asbestos mines — the largest owned by Johns-Manville — near the Quebec communities of Asbestos and Thetford Mines. Demands included the elimination of asbestos dust from inside and outside the mills, a 15-cent an hour wage increase and double time wages for working on Sunday and holidays. The owners rejected the demands. The ensuing strike sparked Quebec’s Quiet Revolution, a period of dramatic socio-political and socio-cultural change in the province.

Asbestos claims haunted the company up until the 1980s, when it filed for bankruptcy protection in 1982 after American asbestos workers sued for more than US$1 billion. The Manville Trust was set up, controlling the majority of the company’s equity, to pay out asbestos claims. In Canada, workers with lung cancer fought for compensation all the way to the Supreme Court of Canada, which ruled in their favour in 1998. By then, only one complainant was still alive. 
In the US, the company emerged from bankruptcy protection in 1988 with a new name, Manville Corporation, re-emerging in 1997 as Johns Manville. The company today, which is owned by Berkshire Hathaway, continues to manufacture a variety of materials, including insulation, for residential and industrial use.