The Johns-Manville Papers: What America’s Largest Asbestos Producer Knew in 1934

This year, a worker who spent his career installing asbestos pipe insulation will receive a mesothelioma diagnosis. He will probably never know that the company whose products he worked with every day of his working life knew — in 1934, nearly four decades before he ever picked up a wrench — that their product was killing him. He will have somewhere between twelve months and several years to live, depending on stage, cell type, and treatment options. He may have legal options he doesn’t know exist.

This is the documented story of what Johns-Manville Corporation knew, when they knew it, and what they chose to do about it.

The Company

Johns-Manville Corporation was, by the mid-twentieth century, the largest asbestos company in the United States. Founded in 1858, by the post-war boom years it operated mines, manufacturing plants, and distribution networks across North America. Its products — pipe insulation, ceiling tiles, floor tiles, roofing materials, joint compound — were installed in virtually every type of American building constructed between 1940 and 1975.

The company was not merely a manufacturer. It was the defining institution of the American asbestos industry, setting prices, lobbying regulators, funding research, and — as the internal documents would eventually reveal — coordinating the suppression of health information across the entire sector.

What the Documents Show

The documents that eventually emerged through litigation discovery — obtained by plaintiffs’ attorneys in the landmark Borel v. Fibreboard case in 1973 — painted a systematic picture of corporate knowledge and deliberate concealment.

As early as 1930, Johns-Manville’s own medical department was aware of research linking asbestos exposure to asbestosis, a progressive and fatal lung disease. Metropolitan Life Insurance Company had completed a survey of workers at the company’s Manville, New Jersey plant. The findings were unambiguous: workers with sustained asbestos exposure showed significantly elevated rates of lung disease.

Johns-Manville negotiated control over the study’s publication. Key findings were omitted from the published version. The workers at the Manville plant were not informed.

By 1934, the company’s position had hardened into formal policy. Internal correspondence from that year — the Simpson-Brown letters — shows that suppression of research findings was not merely tolerated but actively coordinated between the industry’s largest players.

The Legal Strategy

A 1949 memorandum from Johns-Manville’s medical department advises that workers should not be informed of early radiological findings consistent with asbestosis — specifically because notification would create a documentary record usable in future claims. This was not a rogue decision by a single manager. It was company policy, reviewed by legal counsel, applied across multiple facilities.

The company’s legal strategy, developed through the 1950s and 1960s, was built around the same principle: settle cases quietly, avoid creating precedents, and contest any scientific evidence that threatened to establish a definitive causal link between the company’s products and disease.

When Dr. Irving Selikoff of Mount Sinai Hospital published landmark research in 1964 establishing a clear link between asbestos exposure and mesothelioma — a previously rare and invariably fatal cancer — Johns-Manville funded competing research designed to cast doubt on his methodology.

The Bankruptcy and What Came After

By 1982, Johns-Manville faced more than 16,500 pending asbestos lawsuits. The company filed for Chapter 11 bankruptcy — not because it was financially ruined, but as a deliberate legal strategy to cap its liability at a defined amount. The bankruptcy established the Manville Personal Injury Settlement Trust, funded with $2.5 billion, which became the model for the asbestos bankruptcy trust system that would eventually involve more than 60 companies and over $32 billion in total assets.

Johns-Manville continued operating under new ownership. Today it operates as Johns Manville, a subsidiary of Berkshire Hathaway. The trust continues paying claims. Workers who handled Johns-Manville products during their careers — or whose family members did — may still be eligible to file claims against the Manville trust regardless of how long ago the exposure occurred.

What This Looked Like for One Worker

Consider the experience of the men who built post-war America in its shipyards, refineries, and construction sites. A pipefitter who spent thirty years in a Gulf Coast refinery — wrapping pipe with asbestos insulation, cutting lagging, working in the clouds of dust that the work produced — would have had no reason to associate his work with cancer. No one told him. The manufacturer’s installation guidelines said nothing about respiratory risk. His union was not warned. His employer was not warned.

Twenty-five years after his retirement, the diagnosis arrives. Malignant pleural mesothelioma. His doctor, who has seen this before, asks about occupational history. The refinery. The pipes. The dust. He is connected with a mesothelioma attorney, who cross-references his employment history against product databases — and identifies four trust fund claims he didn’t know he had. The trust funds were established specifically because of cases like his: by the manufacturers who knew in 1934, who knew in 1949, who chose not to tell him.

He files the claims. He doesn’t live to see all of them paid. His wife continues the process after his death. It takes another eighteen months. The money does not undo what happened. It was never going to. But it was there, established and waiting, because of the litigation that followed the Borel verdict in 1973 — and because the internal documents of the companies who harmed him were, eventually, obtained.

This is what the Johns-Manville Papers mean in practice. Not as history. As the present.