Monitoring for asbestos: U.S. EPA methods

Our plain-English summary of Monitoring for asbestos: U.S. EPA methods, by K.C. Callahan (Environmental Health Perspectives, 2004).

The study

• Author: K.C. Callahan
• Journal: Environmental Health Perspectives
• Published: 2004;112(13):A728
• Type of article: Comment, Letter
• Read it: PubMed · Publisher · Free full text

In plain English

This is a letter to the editor, not a research study. The author, from U.S. Environmental Protection Agency (EPA) Region 2 in New York, wrote to correct what the author called a misimpression in an article by Landrigan et al. (2004) about how the EPA monitored air for asbestos after the World Trade Center collapsed. The letter said that article suggested the EPA emphasized phase-contrast light microscopy (PCM) over transmission electron microscopy (TEM). The author stated that the EPA began asbestos sampling on the afternoon of September 11 and relied more heavily on TEM, because PCM cannot distinguish asbestos from other mineral fibers. TEM counts were recorded for both short and long asbestos fibers. According to the letter, the EPA's website summarizes 9,604 TEM-analyzed samples from 22 lower Manhattan monitoring stations, not the 8,000 cited in the article. Most samples were also analyzed by PCM, to provide total fiber counts and data for the Occupational Safety and Health Administration. The author concluded that the EPA used the most accepted and appropriate method.

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) correcting a description in a previously published article (Landrigan et al. 2004); no new study was carried out
• Who was studied: Not a study of people. The letter concerns EPA ambient air samples for asbestos from 22 monitoring stations in lower Manhattan after the World Trade Center collapse in September 2001
• Exposure: Airborne asbestos in lower Manhattan after the World Trade Center collapse, as measured by EPA air sampling. The letter discusses two laboratory methods: transmission electron microscopy (TEM) and phase-contrast light microscopy (PCM). No specific fiber type is named.
• Main results:
  • The author stated that the EPA relied more heavily on TEM than on PCM, because PCM cannot distinguish asbestos from other mineral fibers. The author also stated that the suggestion in Landrigan et al. that the EPA emphasized PCM was incorrect.
  • According to the letter, the EPA World Trade Center website summarizes 9,604 asbestos samples from 22 lower Manhattan monitoring stations analyzed by TEM, not the 8,000 samples cited by Landrigan et al.
  • Following Asbestos Hazard Emergency Response Act (AHERA) procedures, TEM counts were recorded for both short and long asbestos fibers.
  • Most samples were also analyzed by PCM. The letter describes this as ancillary information about total fiber counts and data for the Occupational Safety and Health Administration.
• The authors' conclusion: The author concluded that the EPA used the most accepted and appropriate method to protect the health of residents and response workers after the disaster.

Related studies

• Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002 — A.S. Geyh, S. Chillrud, et al. (2005)
• Development of an exposure assessment method for epidemiological studies of New York State personnel who responded to the World Trade Center disaster — M.L. Herdt-Losavio, M.P. Mauer, et al. (2008)
• Evaluation of vacuum and wet-wipe methods for removal of World Trade Center dust from indoor environments — K.M. Tang, C.G. Nace, et al. (2004)
• The legacy of World Trade Center dust — J.M. Samet, A.S. Geyh, et al. (2007)
• Characterization of the dust/smoke aerosol that settled east of the World Trade Center (WTC) in lower Manhattan after the collapse of the WTC 11 September 2001 — P.J. Lioy, C.P. Weisel, et al. (2002)
• Physical characteristics and health effects of aerosols from collapsed buildings — S.H. Gavett (2006)

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