The 1935 Lanza Asbestos Study: 87% Fibrosis, One Edited Sentence

The 1935 Lanza study did not begin as a cover-up. It began as a survey — an honest count of how many Johns-Manville workers had asbestosis after years inside the plant. The cover-up came later, in the editing room, when Johns-Manville's lawyers crossed out a single sentence. The deletion held for 42 years.

What follows is the documented chain of how the country's largest asbestos manufacturer, working with Metropolitan Life Insurance Company, edited a federal public-health publication to protect a litigation defense — and how the evidence that re-emerged in 1977 reshaped American mesothelioma law. For families investigating a diagnosis, the Lanza story is not academic history. It is the foundational record cited in nearly every modern asbestos trust fund and lawsuit decision.

Who Was Dr. Anthony J. Lanza, and Why Did Metropolitan Life Hire Him?

Dr. Anthony J. Lanza was, by 1929, one of the most respected figures in American occupational medicine. Born in New York City in 1884, he trained at George Washington University School of Medicine and joined the U.S. Public Health Service in 1906. Around 1910 he worked with the U.S. Bureau of Mines team in Pitcher, Oklahoma, studying lead miners suffering from chest disease — and he is credited with coining the term "dust disease."

In 1926, Lanza joined Metropolitan Life Insurance Company as Assistant Medical Director, later promoted to Associate Medical Director. The reason was structural. MetLife insured large industrial employers and wrote group life policies on their workers. The company had a direct financial interest in understanding — and managing — the occupational diseases that drove premiums and claims. Lanza became MetLife's in-house expert on industrial lung disease.

In 1929, Johns-Manville and Raybestos-Manhattan, the two largest American asbestos producers, hired MetLife to conduct an industrial-hygiene survey of their plants. The companies needed data. The 1930 Merewether-Price Report from the British Factory Department had found asbestosis in 66% of long-term UK textile workers, and American litigation pressure was building. A controlled, in-house American study could either confirm or counter that finding.

"Dust diseases and the legacy of corporate manipulation of science and law" — the title of David Egilman's 2014 review in the International Journal of Occupational and Environmental Health — describes the Lanza affair as the template for later corporate science manipulation across multiple industries.

— Egilman D, Bird T, Lee C, 2014

Lanza was not, in 1929, a passive academic. As early as November of that year, he sent a bibliography on asbestosis to Allan Wardwell, a partner at Davis and Polk — Johns-Manville's Wall Street corporate counsel. In 1931, he sent survey findings to Wardwell with a written note: "It is, of course, understood that this report is confidential and it will be given no publicity by us except with the consent of the firms concerned." The industry had veto power over publication before a single word was typeset.

What Did the 1932 Lanza Survey Actually Find?

The largest of the Lanza-Meriwether surveys was a cross-sectional examination of all 1,140 employees at the Johns-Manville plant in Manville, New Jersey, conducted in 1932. The methodology was thorough for its era: occupational histories, abbreviated medical histories, physical examinations, fluoroscopy, and chest radiographs interpreted against contemporary pneumoconiosis criteria. The 1932 cohort was later reconstructed in detail in a peer-reviewed 1997 paper in the American Journal of Industrial Medicine, which preserved the original raw data for modern analysis.

The headline finding: 327 of 1,140 subjects (29%) had pneumoconiosis confirmed on x-ray. Among those cases, 64% had prior exposure to dusts in addition to asbestos — coal being the most common second exposure — while 36% had been exposed to asbestos dust alone.

When the data was organized for publication around 1934, the textile-worker subset showed a stark dose-response gradient:

Exposure Duration	Workers Showing Fibrosis on X-Ray
Up to 5 years	43%
5 to 10 years	50%
10 to 15 years	58%
15 years and longer	87%

Across all textile workers combined, 53% showed fibrosis. This is the dataset Johns-Manville's outside counsel sat down with in late 1934, knowing the company was already defending the Pirskowski v. Johns-Manville lawsuit — the first American asbestos personal-injury case, settled in 1933 for $30,000 divided among 11 plaintiffs, with a gag order on plaintiffs' attorney Samuel Greenstone.

How Did Johns-Manville Edit the 1935 Lanza Study?

By December 1934, Lanza had a draft ready for publication in the U.S. Public Health Reports. Galley proofs circulated for review. Johns-Manville general counsel Vandiver Brown — Vice President, Corporate Secretary, and brother of company president Lewis H. Brown — read the galleys and was alarmed by what he saw.

The Hobart Letter and the "Most Serious Consideration"

Brown discussed the paper with George S. Hobart, one of Johns-Manville's outside counsel. On approximately December 15, 1934, Hobart sent Brown a marked-up version of Lanza's paper. Hobart articulated the legal stakes directly:

"One of our principal defenses in actions against the company on account of asbestosis has been that the scientific and medical knowledge has been insufficient until a very recent period to place upon the owners of plants or factories the burden or duty of taking special precautions against the possible onset of the disease to their employees."

— George S. Hobart, outside counsel, Johns-Manville, December 1934

Translated: if the study published as written, Johns-Manville's central defense — that the company did not know asbestos was dangerous — would collapse. Brown forwarded the marked-up galleys to Lanza with his own letter. The tone was carefully euphemistic, coercive while preserving deniability:

"I am sure that you understand fully that no one in our organization is suggesting for a moment that you alter by one jot or tittle any scientific facts or inevitable conclusions revealed or justified by your preliminary survey. All we ask is that all of the favorable aspects of the survey be included and that none of the unfavorable be unintentionally pictured in darker tones than the circumstances justify."

— Vandiver Brown, General Counsel, Johns-Manville, December 1934

The Deleted Sentence — and Why It Mattered

The single most consequential edit was the deletion of one sentence:

"It is possible for uncomplicated asbestosis to result fatally."

That sentence established a medical fact the industry needed to deny: asbestosis alone — without secondary infection, without tuberculosis, without any complication — could kill. Removing it allowed Johns-Manville to argue for decades that asbestosis was a relatively mild condition and that deaths attributed to asbestos exposure were really caused by something else. There is no surviving record of Lanza protesting. He accepted the edits. The censored version was published in U.S. Public Health Reports, Vol. 50, No. 1, on January 4, 1935. A federal court later described it as "allegedly heavily censored," noting that it "minimized or ignored significant data."

Did Lanza Know What He Was Doing? The 1933 Warning Signs Memo

The question of intent matters in fraud-based litigation. The record is unambiguous. In 1933, a Johns-Manville plant physician at the Waukegan, Illinois facility proposed a basic public-health measure: posting signs warning employees that asbestos dust was hazardous. The plant physician asked Lanza directly whether he agreed.

Lanza objected, citing concerns about "the legal situation." In the preserved correspondence, he wrote:

"One of the difficulties and vexations of pneumoconiosis is that economics as well as production factors must be balanced against the medical factors."

— Dr. Anthony J. Lanza, MetLife, 1933

This was not testimony years later. It was contemporaneous written correspondence, relayed through internal Johns-Manville channels by executive George S. Williams to Manville plant manager A.R. Fisher. In the same exchange, Johns-Manville considered transferring an asbestosis-diagnosed worker from the Waukegan plant to operations across the border in Michigan, where no workers' compensation law applied — rather than removing him from dust exposure or notifying him of his condition.

Lanza's role did not end in 1935 or 1947, when he left MetLife to found the Institute of Industrial Medicine at New York University. He served on the board of trustees and Research Advisory Council of the Industrial Hygiene Foundation. He continued as a consultant to the asbestos industry. And he helped fire researchers who tried to publish on asbestos hazards — including Dr. Arthur Vorwald at Saranac Laboratories in 1953 and Dr. W.E. Smith at NYU in 1956. Egilman, Bird, and Lee's 2014 review concluded that Lanza was a willing participant, not a coerced expert.

How Were the Suppressed Documents Discovered in 1977?

For 42 years, the editing correspondence stayed inside Johns-Manville and Raybestos-Manhattan files. No contemporaneous reviewer publicly flagged the alterations. The industry cited the Lanza study favorably for decades as evidence of its "long concern" about asbestos hazards — a striking inversion given that the industry had gutted the report's most damning findings before permitting release.

The discovery came through litigation. In 1977, during Austin v. Johns-Manville Products Corp. in New Jersey, plaintiff's attorney Karl Asch obtained a court order to depose William Simpson — then head of Raybestos-Manhattan and son of former president Sumner Simpson, who had died in 1953. In the deposition, William Simpson revealed that he had found a box of his father's papers: roughly 6,000 pages of internal documents from 1933 to 1943.

The chain of custody was straightforward. Sumner Simpson had kept the documents in a company vault. They passed to William Simpson when his father died. They emerged under subpoena in 1977. The papers included:

• The complete Lanza editing correspondence (December 1934)
• George S. Hobart's letter identifying objectionable statements
• Vandiver Brown's "jot or tittle" forwarding letter to Lanza
• The 1935 Simpson-Brown-Rossiter correspondence with the editor of Asbestos magazine, in which Sumner Simpson wrote: "I think the less said about asbestos, the better off we are," and Vandiver Brown replied: "Our interests are best served by having asbestosis receive the minimum of publicity"
• The Pirskowski settlement and its gag order on the plaintiffs' attorney
• Industry funding contracts with Saranac Laboratory giving sponsors publication veto power

The Austin case settled for $15.5 million before the papers reached the jury. But the documents quickly became the most consequential body of evidence in American asbestos litigation.

How Did the Lanza Documents Change Asbestos Litigation?

Attorney Ron Motley used the newly discovered material to win a new trial in a 1978 asbestos case he had previously lost. The order granting the new trial, issued by the South Carolina Court of Common Pleas in Greenville County on August 23, 1978 in Barnett v. Owens-Corning Fiberglas Corp., found that the correspondence "reflects a conscious effort by the industry in the 1930s to downplay, or arguably suppress, the dissemination of information to employees and the public for fear of the promotion of lawsuits."

In 1984, Judge Harold Ackerman of the U.S. District Court for the District of New Jersey held in Billetz v. Johns-Manville Corp. that Metropolitan Life's conduct supported charges of negligence, fraudulent concealment, and conspiracy. MetLife had collected premiums from the same asbestos companies whose research it shaped — a financial entanglement the court found relevant to the conspiracy claim.

The downstream effects compounded. Punitive-damages awards followed. Ten such awards were entered in 1981 and the first half of 1982 alone, averaging $600,000 per case. By August 1982, Johns-Manville filed for Chapter 11 bankruptcy with 16,500 pending cases and an estimated 52,000 future claims. The Manville bankruptcy in turn produced one of the first major Section 524(g) trusts — the model now used by more than 60 active asbestos bankruptcy trusts holding an estimated $30 billion in assets.

For mesothelioma families today, the Manville Personal Injury Settlement Trust still pays scheduled-value claims. As of 2024 trust filings, the mesothelioma scheduled value remains $350,000, with a payment percentage of approximately 5.1% — meaning an Expedited Review meso claim returns roughly $17,850 from the Manville trust alone. Asbestos trust funds and active-defendant lawsuits are routinely filed in parallel.

What the Lanza Story Means for Mesothelioma Cases in 2026

Three things changed in 1977 that still shape modern mesothelioma lawsuits:

The disputed question is no longer whether the industry knew. The Hobart letter, the Brown letter, the deleted sentence, and the Simpson "less said about asbestos" memo are all in the record. Defense counsel can argue contributory negligence, alternative exposures, or causation specific to one product. They cannot credibly argue, in 2026, that 1930s asbestos manufacturers were operating in ignorance.

Punitive damages have a documentary foundation. Compensatory damages address the patient's loss. Punitive damages address corporate conduct. The Lanza documents reframed conduct as the central question in many cases and made large punitive awards defensible on appeal.

The trust system exists because conduct broke the companies. Section 524(g) of the Bankruptcy Code, codified in 1994, created the legal framework for asbestos personal-injury trusts in part because Johns-Manville and other manufacturers could not survive the conduct-based litigation the Simpson Papers unlocked. Today, families with a pleural mesothelioma diagnosis routinely file with multiple trusts and pursue active defendants simultaneously — a strategy directly traceable to the post-1977 evidentiary record.

For families investigating a diagnosis, the practical implications are unchanged from the 1980s: occupational history matters, product identification matters, and timing matters. Statutes of limitations for mesothelioma generally run from the date of diagnosis, not the date of exposure, but the windows are short — often 1 to 3 years depending on the state. A qualified mesothelioma lawyer can review work history, identify Johns-Manville and other Section 524(g) trust eligibility, and file before the limitations period closes.

Sources and Further Reading

The standing scholarly literature on the Lanza affair is concentrated in three places. Egilman, Bird, and Lee's 2014 review in the International Journal of Occupational and Environmental Health, Dust diseases and the legacy of corporate manipulation of science and law, places the Lanza edits in the broader pattern of corporate science manipulation. Borron and colleagues' 1997 paper in the American Journal of Industrial Medicine, An early study of pulmonary asbestosis among manufacturing workers: original data and reconstruction of the 1932 cohort, preserves the original raw survey data. Paul Brodeur's Outrageous Misconduct (1985) remains the standard narrative reference. Barry Castleman's Asbestos: Medical and Legal Aspects compiles the underlying industry documents across multiple editions. Stephan Landsman's 2025 article in the DePaul Law Review, "Industrywide Corruption in Three American Industries," is the most recent legal scholarship on the litigation history.