PDC 420

Naturally Occurring Asbestos from A to Z: A Comprehensive Assessment







advanced | Credits: 8 CM Credit Hours / 0.8 CEU / 0.5 CMP
Sunday, May 22 | 8:00 AM – 5:00 PM
Limit: 45


Environmental Issues, Exposure Assessment Strategies, Risk Assessment and Management


This course explores methodologies for assessing and managing naturally occurring asbestos (NOA) on construction projects. The course will begin with toxicology and epidemiology background on non-regulated minerals and amphiboles. The course will discuss toxicity values used in the EPA’s 2008 Asbestos Framework document and the recent IRIS Toxicological Review of Libby Amphibole Asbestos. Fundamentals and methodologies required to conduct a hazard identification for NOA that is consistent with regulatory requirements and geologic standard of practice will be presented. Class participants will learn how to select the appropriate sampling and testing protocol, and interpret results. Participants will learn fundamentals of Gaussian Dispersion Modeling, including hands-on experience using an EPA-approved screening level dispersion model. Case study examples will show how toxicity values can be used to develop risk_based air concentration criteria, and how dispersion modeling can be used in the derivation of perimeter air thresholds that are protective of offsite receptors. The course will discuss other minerals that can form finely fibrous crystals, including palygorskite, brucite, sepiolite, and talc. Participants will learn about erionite (believed to be the cause of environmental mesothelioma in Turkey. A concluding section of risk communication and risk perception will complete this course.


Knowledge of exposure assessment and risk assessment principles. Knowledge of statistics and uncertainty. General knowledge of meteorology and pollutant dispersion.

Learning Aids

Participants must bring a scientific calculator and laptop.

Value Added

Screening Level Dispersion Model will be provided as well as U.S. EPA’s ‘Screening Procedures for Estimating the Air Quality Impacts of Stationary Sources.


Upon completion, participants will be able to:

  • Demonstrate geological and mineralogical concepts related to naturally occurring asbestos and other EMPs.
  • Discuss site assessment and analytical considerations for naturally occurring asbestos.
  • Explain the effects of wind speed, turbulence, and atmospheric stability on dispersion of airborne pollutants.
  • Calculate an emission factor for hypothetical airborne emissions using a box model and Gaussian dispersion algorithm.
  • Demonstrate the use of emission factors in a screening level model to predict airborne concentrations downwind from a source.
  • Use an Excel spreadsheet to calculate a risk-based concentration using an established inhalation unit risk value.
  • Use dispersion techniques to predict offsite concentrations, and identify protective perimeter air concentrations.
  • Identify the benefits and limitations of risk management tools.


  • Background on the Toxicology and Epidemiology of Elongated Mineral Particles and Amphiboles
  • Site Characterization and Mineralogy
  • Meteorology and Dispersion
  • Hands on Modeling Laboratory
  • Development of Risk-Based Air Concentration Criteria and Air Monitoring Methods
  • Emissions Inventory Measurements, H&S Management, Site Controls, Dust Controls, Decontamination
  • New Horizons
  • Concluding Remarks with Risk Communication and Perception

Transfer of Knowledge

Instructors will evaluate participants understanding of the materials presented based on:

  • Hands-on demonstrations and practicum
  • Practice exercises
  • Group activities

Course Survey Link: https://www.surveymonkey.com/r/16PDC420

Sponsoring Committee

Risk Assessment