Asbestos on Maryland's roads

Our plain-English summary of Asbestos on Maryland's roads, by A.M. Langer, A.N. Rohl, I.J. Selikoff (Lancet, 1978).

The study

• Authors: A.M. Langer, A.N. Rohl, I.J. Selikoff
• Journal: Lancet
• Published: 1978;1(8076):1263-4
• Type of article: Letter
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor of The Lancet, not a full research paper. The authors disputed a Lancet news item suggesting that asbestos concern in Rockville, Montgomery County, Maryland, was an unnecessary scare. They described their own sampling in 1976. Rock from the Rockville quarry, crushed stone from roads, and dust from roadside vegetation were examined by microscopy and X-ray methods. The authors reported that these samples were mineralogically identical and highly contaminated with chrysotile asbestos fibres. The crushed stone contained several tenths of a percent chrysotile. Air sampled near roads surfaced with this crushed serpentinite had levels of 500 to 4700 ng/m3. For comparison, the letter cited levels of 0.1 ng/m3 at non-urban sites and 0.5 to 15 ng/m3 at urban sites in the United States. The authors stated that the crushed rock had been used on over a hundred miles of roads and on school play yards, and that the finer dust had filled children's sandboxes in over 200 county parks. The authors concluded that county authorities were correct to be concerned. According to the letter, the authorities had since covered such areas with asphalt and similar materials.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Letter to the editor (correspondence) replying to a Lancet news item, describing the authors' environmental sampling of rock, dust, water and air
• Who was studied: Environmental samples, not people: rock and minerals from the Rockville quarry, crushed stone from roads, dust from roadside vegetation, and water from the quarry and its streams (early summer 1976), plus air sampled at sites including homes and schools near roads (November 1976), Montgomery County, Maryland
• Exposure: Chrysotile asbestos in crushed serpentine rock (serpentinite) from the Rockville quarry, used for road surfacing, often laid loose
• Main results:
  • Quarry specimens, road material and dusts were mineralogically identical and highly contaminated with chrysotile asbestos fibres
  • Air near Maryland roads surfaced with crushed serpentinite had levels ranging from 500 to 4700 ng/m3
  • For comparison, the letter cited levels of 0.1 ng/m3 at non-urban sites and 0.5 to 15 ng/m3 at urban sites (the scanned text does not make clear which cited study these figures come from)
  • The authors' laboratory's earlier study of air in forty-nine U.S. cities, done for the EPA with the same techniques, found an average concentration of 2.1 ng/m3 in 1970 (the 1969 figure is garbled in the scan)
  • The authors stated that the crushed rock containing chrysotile had been used on over a hundred miles of roads in Montgomery and Prince George County and the District of Columbia, for some twenty years
  • The authors stated that the crushed rock had also been used on parking lots, school play yards, drives and paths, and that the finer dust had been used to fill children's sandboxes in over 200 county parks
  • The authors stated that county authorities had since covered such areas with asphalt and similar materials
  • In an EPA comparison of laboratories, the two laboratories that used similar sample preparation and instrumental methods achieved almost identical results
  • The authors pointed out that the National Institute for Occupational Safety and Health study cited by the news item involved workers employed for less than 20 years, which they described as too short a latency period to expect overt disease
• The authors' conclusion: The authors concluded that the county authorities were correct to be concerned about residents driving in asbestos-containing dust and children playing on loose crushed asbestos-containing stone

Related studies

• Evaluation of public and worker exposure due to naturally occurring asbestos in gravel discovered during a road construction project — R.A. Perkins, J. Hargesheimer, et al. (2008)
• Exposure to naturally occurring mineral fibers due to off-road vehicle use: A review — C. Wolfe, B. Buck, et al. (2017)
• Asbestos distribution in the Central Serpentine District of Maryland-Pennsylvania — J.H. Puffer, M. Germine, et al. (1980)
• Environmental asbestos pollution related to use of quarried serpentine rock — A.N. Rohl, A.M. Langer, et al. (1977)
• Mesothelioma incidence in 50 states and the District of Columbia, United States, 2003-2008 — S.J. Henley, T.C. Larson, et al. (2013)
• Asbestos exposure during brake lining maintenance and repair — A.N. Rohl, A.M. Langer, et al. (1976)

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