New reports from the NIOSH health hazard evaluation program

Our plain-English summary of New reports from the NIOSH health hazard evaluation program (International Journal of Occupational and Environmental Health, 2015).

The study

• Journal: International Journal of Occupational and Environmental Health
• Published: 2015;21(2):180-1
• Read it: PubMed · Publisher · Free full text

In plain English

This item presents short summaries of three NIOSH Health Hazard Evaluations; only one, described here, concerns asbestos. Managers of the Kootenai National Forest in Montana asked NIOSH to evaluate employees' possible exposure to Libby amphibole during forest management and fire suppression work around a former vermiculite mine. The site had about 40 full-time employees and up to 100 more in summer. The evaluators observed work and protective equipment use. They collected personal air samples, bulk samples of bark, duff and soil, and wipe and vacuum samples from a hydrology lab. Six of 109 air samples analyzed by PCM exceeded the occupational exposure limit of 0.1 f/cc, but non-asbestos material meeting the definition of a fiber was found on them. Of 27 samples examined by TEM, six contained mineral fibers. Five contained richterite, a component of Libby amphibole: four from fireline construction and one from tree thinning. One contained chrysotile. No Libby amphibole was found in bulk or surface samples. The authors concluded that employee exposures to Libby amphibole did not exceed occupational exposure limits during activities in the mine area. Their recommendations included a respirator program and periodic monitoring.

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: Workplace health hazard evaluation (exposure assessment by observation and air, bulk and surface sampling), reported here as a brief summary of a NIOSH report
• Who was studied: Employees serving the Kootenai National Forest in Montana working in an area surrounding a former vermiculite mine; approximately 40 full-time employees and up to 100 additional employees in summer. Dates are not given in this summary.
• Exposure: Libby amphibole (and asbestos generally) during forest management and wildland fire suppression activities, including fireline construction, tree thinning, trail maintenance and fuel reduction
• Main results:
  • Six of 109 personal air samples analyzed by PCM exceeded the occupational exposure limit of 0.1 f/cc, but non-asbestos material meeting the definition of a fiber was found on these samples
  • Of 27 personal air samples evaluated by TEM (including the six above 0.1 f/cc), six contained mineral fibers: five contained richterite and one contained chrysotile
  • Of the five samples containing richterite, four were collected during fireline construction and one during tree thinning
  • No Libby amphibole was detected in the bulk (bark, duff, soil) or surface samples
  • Employees wore respirators during trail maintenance and fuel reduction activities and completed a 3-stage decontamination
• The authors' conclusion: The authors concluded that employee exposures to Libby amphibole did not exceed occupational exposure limits during activities in the mine area. They recommended a respirator program, periodic exposure monitoring, electron microscopy analysis for Libby amphibole, scheduling dusty work when dust potential is low, and training on work practices to minimize dust.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Libby vermiculite mine, Montana

All asbestos mines

Topics

Medical terms in this study, explained in our Lexicon: NIOSH.

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