Who was the largest manufacturer of asbestos?

The largest manufacturer of asbestos in United States and one of largest in world was Johns Manville Corporation, which dominated asbestos production for much of 20th century, producing majority of asbestos products used in construction and industry. Johns Manville, founded in 1858 as H.W. Johns Manufacturing Company in New York, became largest asbestos manufacturer by early 1900s after merging with Manville Covering Company in 1901, producing asbestos insulation, roofing, cement, pipe covering, and brake linings, with plants across US and controlling large portion of asbestos market, at peak producing over 50 percent of asbestos products in US, with sales over 2 billion dollars in 1970s and over 30,000 employees. Other large asbestos manufacturers included Owens Corning which made asbestos insulation, Armstrong World Industries, GAF Corporation, and Raybestos-Manhattan, but Johns Manville was largest. Globally, largest asbestos producers included Johns Manville in US, Cape Asbestos in UK, and Russian and Canadian mining companies producing raw asbestos. Johns Manville's dominance led to massive liability when health risks of asbestos causing asbestosis, mesothelioma, and lung cancer became known, leading to thousands of lawsuits and Chapter 11 bankruptcy in 1982, largest bankruptcy at time, creating trust fund for victims. After reorganization, Johns Manville exited asbestos business in late 1980s and now makes fiberglass insulation and roofing as subsidiary of Berkshire Hathaway since 2001, with plant in Innisfail, Alberta, Canada.