Marinite

Marinite is a brand name for a family of rigid, high-density insulating boards manufactured by Johns-Manville beginning in the 1930s. Earlier formulations (through roughly the early 1980s) contained substantial amounts of asbestos (typically chrysotile, sometimes with amphibole fibers) bound in a calcium silicate or diatomaceous earth matrix. Marinite was prized for its fire resistance, structural strength, and machinability, and it was widely installed in ships, power plants, ovens, kilns, and laboratory benchtops.

Origin

The name derives from the product's original marine application. It was developed by Johns-Manville in the 1930s as a fireproof bulkhead and partition material for U.S. Navy and merchant ships. The trade name was retained through multiple reformulations and is still used today, though modern Marinite is asbestos-free. According to the 1986 Sourcebook on Asbestos Diseases, a compilation by plaintiffs' attorneys, a company called Marinite Ltd. became a wholly owned subsidiary of the Cape Asbestos Co. Ltd.¹

Significance in Asbestos Context

Marinite is one of the most commonly identified asbestos-containing products in shipyard, Navy, and industrial mesothelioma cases. Because it was cut, drilled, sanded, and sawed on site to fit bulkheads, furnaces, and laboratory casework, it released respirable fibers directly into the breathing zone of workers and anyone nearby. Identifying Marinite in a patient's exposure history can be powerful evidence because the product is well-documented, the manufacturer is known, and the asbestos content of pre-1980s formulations is established in the scientific and litigation record. Patients who worked on ships, in boiler rooms, in laboratories with fume hoods or benchtops, or in high-temperature industrial settings should specifically be asked whether they handled or worked near Marinite board.

Example Sentence

The industrial hygienist's report identified Marinite panels cut during the 1972 refit of the destroyer as a likely source of the patient's asbestos exposure.

Related Terms

Calcium Silicate Insulation, Chrysotile, Johns-Manville, Shipyard Exposure, Transite, Product Identification

Notes

• If you or a family member worked in shipyards, the Navy, power plants, refineries, or laboratories, try to recall whether you handled rigid white or off-white insulating boards used as bulkheads, furnace linings, oven panels, or benchtops, and note this for your legal team.
• Preserve any photographs, ship records, work logs, purchase orders, or co-worker contacts that could help confirm Marinite was present at your worksite during the asbestos-containing era (pre-1980s).
• Ask your attorney whether a product identification expert or industrial hygienist should review your work history; Marinite has well-developed evidentiary records tied to Johns-Manville's bankruptcy trust and successor trusts.
• Modern Marinite sold today is asbestos-free, so the date of installation and the date of your exposure, not the brand name alone, determines whether asbestos was involved.

References

1. Barbara J. Peters and George A. Peters, Sourcebook on Asbestos Diseases: Medical, Legal, and Engineering Aspects, vol. 2 (New York: Garland Law Publishing, 1986), p. 159.