• Notice
• Subcommittee
• Preface
• Contents
• Summary

NATIONAL ACADEMY PRESS
Washington, D.C., 1997

NATIONAL ACADEMY PRESS • 2101 Constitution Avenue, N.W. • Washington, DC 20418

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.

This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.

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The project was supported by the U.S. Department of Defense under contract DAMD 17-89-C-9086.
Additional copies of this report are available from the Board on Environmental Studies and Toxicology, 2101 Constitution Avenue, NW, Washington, DC 20418.


Copyright ©1997 by the National Academy of Sciences. All rights reserved.

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Subcommittee on the Assessment of
Military Smokes and Obscurants


MICHELE A. MEDINSKY (Chair), Chemical Industry Institute of Toxicology, Research Triangle Park, N.C.
DEBORAH A. CORY-SLECHTA, University of Rochester School of Medicine, Rochester, N.Y.
CHARLES E. FEIGLEY, University of South Carolina School of Public Health, Columbia, S.C.
DONALD E. GARDNER, Inhalation Toxicology Associates, Raleigh, N.C.
SIDNEY GREEN, Corning Hazelton, Inc., Vienna, Va.
ROGENE F. HENDERSON, Lovelace Biomedical and Environmental Research Institute, Albuquerque, N.Mex.
CAROLE A. KIMMEL, U.S. Environmental Protection Agency, Washington, D.C.

Staff

KULBIR S. BAKSHI, Program Director for the Committee on Toxicology
MARGARET M. MCVEY, Project Director
RUTH E. CROSSGROVE, Editor
CATHERINE M. KUBIK, Senior Program Assistant
LINDA V. LEONARD, Senior Project Assistant
LUCY V. FUSCO, Program Assistant

Sponsor: U.S. Department of Defense

Committee on Toxicology


ROGENE F. HENDERSON (Chair), Lovelace Biomedical and Environmental Research Institute, Albuquerque, N.Mex.
DONALD E. GARDNER (Vice-Chair), Inhalation Toxicology Associates, Raleigh, N.C.
GERMAINE M. BUCK, State University of New York at Buffalo, N.Y.
DEBORAH A. CORY-SLECHTA, University of Rochester, Rochester, N.Y.
KEVIN E. DRISCOLL, Procter & Gamble Company, Cincinnati, Ohio
ELAINE M. FAUSTMAN, University of Washington, Seattle, Wash,
CHARLES E. FEIGLEY, University of South Carolina, Columbia, S.C.
DAVID W. GAYLOR, U.S. Food and Drug Administration, Jefferson, Ark.
IAN A. GREAVES, University of Minnesota, Minneapolis, Minn.
SIDNEY GREEN, Corning Hazleton, Inc., Vienna, Va.
WILLIAM E. HALPERIN, National Institute for Occupational Safety and Health, Atlanta, Ga.
LOREN D. KOLLER, Oregon State University, Corvallis, Oreg.
GEORGE B. KOELLE, University of Pennsylvania, Philadelphia, Pa.
DANIEL KREWSKI, Health Canada, Ottawa, Ontario
THOMAS E. MCKONE, University of California, Berkeley, Calif.
MICHELE A. MEDINSKY, Chemical Industry Institute of Toxicology, Research Triangle Park, N.C.
JOHN L. O'DONOGHUE, Eastman Kodak Company, Rochester, N.Y.
ROBERT SNYDER, Environmental and Occupational Health Sciences Institute, Piscataway, N.J.
BERNARD M. WAGNER, Wagner Associates, Inc., Millburn, N.J.
BAILUS WALKER JR., Howard University, Washington, D.C.
ANNETTA P. WATSON, Oak Ridge National Laboratory, Oak Ridge, Tenn.
HANSPETER R. WITSCHI, University of California, Davis, Calif.
GAROLD S. YOST, University of Utah, Salt Lake City, Utah

Staff of the Committee on Toxicology

KULBIR S. BAKSHI, Program Director
MARGARET E. MCVEY, Program Officer
RUTH E. CROSSGROVE, Editor
CATHERINE M. KUBIK, Senior Program Assistant
LUCY V. FUSCO, Program Assistant
LINDA V. LEONARD, Senior Project Assistant

Board on Environmental Studies and Toxicology


PAUL G. RISSER (Chair), Oregon State University, Corvallis, Oreg.
MAY R. BERENBAUM, University of Illinois, Urbana, Ill.
EULA BINGHAM, University of Cincinnati, Cincinnati, Ohio
PAUL BUSCH, Malcolm Pirnie, Inc., White Plains, N.Y.
EDWIN H. CLARK II, Clean Sites, Inc., Alexandria, Va.
ELLIS COWLING, North Carolina State University, Raleigh, N.C.
GEORGE P. DASTON, The Procter & Gamble Co., Cincinnati, Ohio
PETER L. DEFUR, Virginia Commonwealth University, Richmond, Va.
David L. Eaton, University of Washington, Seattle, Wash.
DIANA FRECKMAN, Colorado State University, Ft. Collins, Colo.
ROBERT A. FROSCH, Harvard University, Cambridge, Mass.
DANIEL KREWSKI, Health & Welfare Canada, Ottawa, Ontario
RAYMOND C. LOEHR, The University of Texas, Austin, Tex.
WARREN MUIR, Hampshire Research Institute, Alexandria, Va.
GORDON ORIANS, University of Washington, Seattle, Wash.
GEOFFREY PLACE, Hilton Head, S.C.
BURTON H. SINGER, Princeton University, Princeton, N.J.
MARGARET STRAND, Bayh, Connaughton and Malone, Washington, D.C.
BAILUS WALKER, JR., Howard University, Washington, D.C.
GERALD N. WOGAN, Massachusetts Institute of Technology, Cambridge, Mass.
TERRY F. YOSIE, E. Bruce Harrison Co., Washington, D.C.

Staff

JAMES J. REISA, Director
DAVID J. POLICANSKY, Associate Director and Program Director for Natural Resources and Applied Ecology
CAROL A. MACZKA, Program Director for Toxicology and Risk Assessment
LEE R. PAULSON, Program Director for Information Systems and Statistics
RAYMOND A. WASSEL, Program Director for Environmental Sciences and Engineering

Commission on Life Sciences


THOMAS D. POLLARD (Chair), The Salk Institute, La Jolla, Calif.
FREDERICK R. ANDERSON, Cadwalader, Wickersham & Taft, Washington, D.C.
JOHN C. BAILAR III, University of Chicago, Chicago, Ill.
PAUL BERG, Stanford University School of Medicine, Stanford, Calif.
JOHN E. BURRIS, Marine Biological Laboratory, Woods Hole, Mass.
SHARON L. DUNWOODY, University of Wisconsin, Madison, Wisc.
URSULA W. GOODENOUGH, Washington University, St. Louis, Mo.
HENRY W. HEIKKINEN, University of Northern Colorado, Greeley, Colo.
HANS J. KENDE, Michigan State University, East Lansing, Mich.
SUSAN E. LEEMAN, Boston University School of Medicine, Boston, Mass.
THOMAS E. LOVEJOY, Smithsonian Institution, Washington, D.C.
DONALD R. MATTISON, University of Pittsburgh, Pittsburgh, Pa.
JOSEPH E. MURRAY, Wellesley Hills, Mass.
EDWARD E. PENHOET, Chiron Corporation, Emeryville, Calif.
EMIL A. PFITZER, Research Institute for Fragrance Materials, Hackensack, N.J.
MALCOLM C. PIKE, University of Southern California, Los Angeles, Calif.
HENRY C. PITOT III, University of Wisconsin, Madison, Wisc.
JONATHAN M. SAMET, The johns Hopkins University, Baltimore, Md.
CHARLES F. STEVENS, The Salk Institute, La Jolla, Calif.
JOHN L. VANDEBERG, Southwest Foundation for Biomedical Research, San Antonio, Tex.

PAUL GILMAN, Executive Director

Other Recent Reports of the
Board on Environmental Studies and Toxicology


Carcinogens and Anticarcinogens in the Human Diet: A Comparison of Naturally Occurring Synthetic and Natural Substances (1996)
Upstream: Salmon and Society in the Pacific Northwest (1996)
Science and the Endangered Species Act (1995)
Wetlands: Characteristics and Boundaries (1995)
Biologic Markers (Urinary Toxicology (1995), Immunotoxicology (1992), Environmental Neurotoxicology (1992), Pulmonary Toxicology (1989), Reproductive Toxicology (1989))
Review of EPA's Environmental Monitoring and Assessment Program (three reports, 1994-1995)
Science and Judgment in Risk Assessment (1994)
Ranking Hazardous Sites for Remedial Action (1994)
Pesticides in the Diets of Infants and Children (1993)
Issues in Risk Assessment (1993)
Setting Priorities for Land Conservation (1993)
Protecting Visibility in National Parks and Wilderness Areas (1993)
Dolphins and the Tuna Industry (1992)
Environmental Neurotoxicology (1992)
Hazardous Materials on the Public Lands (1992)
Science and the National Parks (1992)
Animals as Sentinels of Environmental Health Hazards (1991)
Assessment of the U.S. Outer Continental Shelf Environmental Studies Program, Volumes I-IV (1991-1993)
Human Exposure Assessment for Airborne Pollutants (1991)
Monitoring Human Tissues for Toxic Substances (1991)
Rethinking the Ozone Problem in Urban and Regional Air Pollution (1991)
Decline of the Sea Turtles (1990)
Tracking Toxic Substances at Industrial Facilities (1990)

Copies of these reports may be ordered from the National Academy Press
(800) 624-6242 or (202) 334-3313

Other Recent Reports of the Committee on Toxicology


Toxicity of Alternatives to Chlorofluorocarbons: HFC-134a and HCFC-123 (1996)
Permissible Exposure Levels for Selected Military Fuel Vapors (1996)
Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume I (1994), Volume 2 (1996), and Volume 3 (1996)
Nitrate and Nitrite in Drinking Water (1995)
Guidelines for Chemical Warfare Agents in Military Field Drinking Water (1995)
Review of the U.S. Naval Medical Research Institute's Toxicology Program (1994)
Health Effects of Permethrin-Impregnated Army Battle-Dress Uniforms (1994)
Health Effects of Ingested Fluoride (1993)
Guidelines for Developing Community Emergency Exposure Levels for Hazardous Substances (1993)
Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants (1992)
Review of the U.S. Army Environmental Hygiene Agency Toxicology Division (1991)
Permissible Exposure Levels and Emergency Exposure Guidance Levels for Selected Airborne Contaminants (1991)

Preface

U.S. Army personnel are exposed to various smokes and other obscurants during combat training. This report is intended to assist the Army in its efforts to ensure that exposures to these substances do not adversely effect the health of military personnel or the public living and working near military-training facilities. In this report, the National Research Council's Subcommittee on Military Smokes and Obscurants reviews the available toxicity data on four obscuring smokes—fog oil, diesel fuel, red phosphorus, and hexachloroethane—and develops exposure guidance levels for each.

The subcommittee was greatly assisted by several individuals who provided information on the uses and toxicity of the smokes considered in this report. We gratefully acknowledge Colonel Francis L. O'Donnell, Major James Martin, Lieutenant Colonel Forrest Oliverson, and the Office of the Surgeon General of the U.S. Army for their interest and support of this project. We also thank other persons who provided information for the subcommittee, including Winnifred Palmer, Sandra Thomson, Stephen Kistner, and Michael Burnham (all from the U.S. Army), Ian Greaves (University of Minnesota), David Gaylor (U.S. Food and Drug Administration), and Catherine Aranyi (IIT Research Institute).

We are grateful for the assistance of the NRC staff in the preparation of this report. In particular, the subcommittee wishes to acknowledge Kulbir S. Bakshi, program director for the Committee on Toxicology, and Margaret E. McVey, project director for the subcommittee. Other staff members who contributed to this effort are Paul Gilman, executive director of the Commission on Life Sciences; James J. Reisa, director of the Board on Environmental Studies and Toxicology; Carol A. Maczka, program director for toxicology and risk assessment; Ruth E. Crossgrove, editor; and Lucy Fusco and Linda V. Leonard, project assistants.

Finally, we would like to thank all the members of the subcommittee for their expertise and dedicated effort throughout development of this report.




Michele A. Medinsky, Ph.D.
Chair, Subcommittee on Military
Smokes and Obscurants

Rogene F. Henderson, Ph.D.
Chair, Committee on Toxicology

Contents




LIST OF ABBREVIATIONS

SUMMARY


1 INTRODUCTION
  Smokes Reviewed in this Report
  U.S. Army Policy Concerning Use of Obscurants
  Subcommittee Task
  Definitions of Exposure Guidance Levels
  Approach to Developing Exposure Guidance Levels
  Summary of Approach
  References

2 DIESEL-FUEL SMOKE
  Background Information
  Toxicokinetics
  Toxicity Summary
  Existing Recommended Exposure Limits
  Subcommittee Evaluation and Recommendations
  Research Needs
  References

3 FOG-OIL SMOKE
  Background Information
  Toxicokinetics
  Toxicity Summary
  Existing Recommended Exposure Limits
  Subcommittee Evaluation and Recommendations
  Research Needs
  References

4 RED PHOSPHORUS SMOKE
  Background Information
  Toxicokinetics
  Toxicity Summary: Elemental Red Phosphorus
  Toxicity Summary: Red Phosphorus-Butyl Rubber
  Existing Recommended Exposure Limits
  Subcommittee Evaluation and Recommendations
  Research Needs
  References

5 HEXACHLOROETHANE SMOKE
  Background Information
  Toxicokinetics
  Toxicity Summary
  Existing Recommended Exposure Limits
  Subcommittee Evaluation and Recommendations
  Research Needs
  References

List of Abbreviations

Summary


A variety of smokes and obscurants have been developed and used in wartime operations to screen armed forces from view, signal friendly forces, and identify enemy targets. Obscurants are anthropogenic or naturally occurring particles that are suspended in the air and block or weaken transmission of a particular part or parts of the electromagnetic spectrum, such as visible and infrared radiation or microwaves. Fog, mist, and dust are examples of obscurants. Smokes are produced by burning or vaporizing some product.

Large quantities of smokes and other obscurants are used in military training. The U.S. Army wishes to ensure that exposure to smokes and obscurants during training does not have adverse health effects on military personnel. To protect the health of exposed individuals, the Office of the Army Surgeon General requested that the National Research Council (NRC) review data on the toxicity of smokes and obscurants and recommend exposure guidance levels for military personnel in training and for the general public residing or working near military-training facilities.

The NRC assigned this project to the Committee on Toxicology (COT), which convened the Subcommittee on Military Smokes and Obscurants. The subcommittee conducted a detailed evaluation of data on the toxicity of four obscurant smokes: fog oil, diesel fuel, red phosphorus, and hexachloroethane. Toxicity data and exposure guidance levels for other smokes and obscurants will be presented in subsequent volumes.

The Army requested recommendations for four types of exposure limits: (1) emergency exposure guidance levels (EEGLs) for a rare, emergency situation resulting in exposure of military personnel for less than 24 hrs; (2) permissible exposure guidance levels (PEGLs) for repeated exposure of military personnel during training exercises; (3) short-term public emergency guidance levels (SPEGLs) for a rare, emergency situation potentially resulting in an exposure of the public to military-training smoke; and (4) permissible public exposure guidance levels (PPEGLs) for repeated accidental exposures of the public residing or working near military-training facilities.


EXPOSURE GUIDANCE LEVELS
FOR MILITARY PERSONNEL
Using NRC guidelines published in 1986 and 1992 for developing exposure guidance levels, the subcommittee developed EEGLs and PEGLs for the four obscuring smokes as shown in Table S-1 and described below.


Diesel-Fuel Smoke
Diesel-fuel smoke is formed by injecting diesel fuel into the exhaust manifold of a tactical vehicle. The fuel is vaporized and expelled with the vehicle's exhaust. The vapor condenses when exposed to the atmosphere, producing a visual obscurant composed of respirable particles.

Although extensive data are available on the health effects of combusted diesel-fuel exhaust, little information is available on the health effects of uncombusted diesel-fuel smoke. The mortality of rodents following one-time exposure depends on the product of exposure concentration and time (CT). One-time and repeated exposures to diesel-fuel smoke produce adverse effects in the respiratory tract of rats and mice. Toxic effects include pulmonary congestion, bronchopneumonia, bronchitis, edema, and hemorrhage. In several studies, diesel-fuel was neither neurotoxic nor genotoxic. In one developmental toxicity study, a slight delay in skeletal development was observed in rats; however, in several other studies, developmental or reproductive toxicity was not observed.

For diesel-fuel smoke, the subcommittee developed EEGLs on the basis of an estimate of the CT product that induces a 1% mortality of rats following a single exposure for 2 to 6 hr (i.e., a CT product of 8,200 milligrams per cubic meter multiplied by hour (mg·hr/m³)). Considering the severity of the end point (death), the subcommittee divided the CT product by an uncertainty factor of 10 to predict a nonpermanent health impairment and by another uncertainty factor of 10 to account for interspecies differences in sensitivity. The result is an EEGL (expressed as a CT product) of 80 mg·hr/m³. Assuming that Haber's law applies in the absence of evidence to the contrary, the 15-min EEGL is 300 mg/m³, the 1-hr EEGL is 80 mg/m³, and the 6-hr EEGL is 15 mg/m³.

The subcommittee based the PEGL on a lowest-observed-adverse-effect level (LOAEL) of 8,000 mg·hr/m³ per week for focal pneumonitis in rats exposed for 9 weeks. The LOAEL was divided by an uncertainty factor of 10 to estimate a no-observed-adverse-effect level (NOAEL) and by another uncertainty factor of 10 to account for interspecies differences in sensitivity. The resulting PEGL, expressed as a CT product, is 80 mg·hr/m³ per week. That PEGL corresponds to a PEGL of 10 mg/m³ for one 8-hr exposure per week and 5 mg/m³ for two 8-hr exposures per week. The subcommittee recommends those PEGLs as ceiling values; in other words, those PEGLs apply even if the exposure events are less than 8 hr in a given day. The subcommittee also recommends that protective equipment be worn if exposures to diesel-fuel smoke during training appears to produce chronic dermatitis in any individuals.


Fog-Oil Smoke
Fog-oil smoke is the term used for an oil smoke generated by injecting mineral oil into a heated manifold. As for diesel-fuel smoke, the fog-oil vapors condense when exposed to the atmosphere, producing respirable particles. The chemical and physical properties of fog oil are similar to those of petroleum-based lubricating and cutting oils.

In this report, the subcommittee distinguishes between "old" and "new" fog oil. Conventionally refined mineral oils, including old fog oil, can cause cancer of the skin of the arms, hands, and scrotum of humans. Polycyclic aromatic hydrocarbons (PAHs) and related compounds in conventionally refined mineral oils are thought to be responsible for those effects. In 1986, the military changed its specifications for fog oil and required severe solvent refining or severe hydro-treatment of fog oil to remove carcinogenic or potentially carcinogenic constituents. Severely refined fog oil is referred to as new fog oil.

Because of the carcinogenic properties of conventionally refined mineral oils, the subcommittee endorses existing Army recommendations that fog oil purchased before revision of the military specifications in 1986 no longer be used to produce smoke. The subcommittee also endorses Army recommendations that fog oil purchased after the specifications were revised be tested for carcinogenic constituents to ensure that all batches are free of carcinogens. The subcommittee's exposure guidance levels described below apply to new fog oils only.

The most sensitive toxic end point following short- and long-term exposures to new fog-oil aerosols in humans and animals appears to be respiratory-tract toxicity. To develop EEGLs, the subcommittee divided a 2-hr LOAEL of 4,500 mg/m³ for pulmonary effects in mice by an uncertainty factor of 10 to estimate a NOAEL from a LOAEL and by another uncertainty factor of 10 to account for interspecies differences in sensitivity. The resultant EEGL is 45 mg/m³ for 2 hr. Assuming Haber's law applies in the absence of evidence to the contrary, the 15-min EEGL is 360 mg/m³, the 1-hr EEGL is 90 mg/m³, and the 6-hr EEGL is 15 mg/m³. The PEGL of 5 mg/m³ is based on a study that indicated few, if any, complaints from workers exposed at or below that level.


Red Phosphorus Smoke
Red phosphorus smoke is deployed explosively from grenades and mortar shells. The obscurant portion of the grenades consists of a 95:5 mixture of red phosphorus and butyl rubber, which, when combusted, produces aerosols of phosphoric acid in a complex mixture of polymeric forms.

The high phosphoric acid content of the smoke causes respiratory-tract irritation and inflammation in humans and animals at concentrations of 180 mg/m³. Inhalation of red phosphorus-butyl rubber smoke by rats produces terminal bronchiolar fibrosis. Induction of fibrosis appears to be influenced by both concentration and duration of exposure.

The most sensitive toxic effect following short-term exposures of humans and animals to red phosphorus-butyl rubber aerosols is respiratory distress. Concentrations as low as 100 mg/m³ are considered to be intolerable to humans, even for short periods. Data from dogs and rats indicate that exposure to approximately 1,200 mg/m³ for 1 hr induces respiratory distress. Dividing by an uncertainty factor of 10 to account for interspecies differences in sensitivity and by another uncertainty factor of 10 to estimate a NOAEL from a LOAEL, the subcommittee developed a 1-hr EEGL of 10 mg/m³. Assuming Haber's law applies over relatively short exposure durations in the absence of evidence to the contrary, the 15-min EEGL is 40 mg/m³, and the 6-hr EEGL is 2 mg/m³.

The PEGL recommended for red phosphorus-butyl rubber is based on the American Conference of Governmental Industrial Hygienist's (ACGIH) Threshold Limit Value (TLV) time-weighted average (TWA) for phosphoric acid, which is the primary combustion product of concern. The TLV-TWA of 1.0 mg/m³ appears to protect occupational workers adequately and, therefore, seems appropriate for military personnel as well.


Hexachloroethane Smoke
Hexachloroethane (HCE) smoke (often referred to as HC smoke) is produced by burning a mixture containing roughly equal parts of HCE and zinc oxide and approximately 6% granular aluminum. The toxicity of HC smoke is attributed to the production of zinc chloride (ZnCl₂). Fatalities have occurred when military personnel were exposed to the discharge of HC smoke devices in enclosed spaces.

Inhalation of HC smoke causes respiratory effects in humans and animals. Data from humans indicate a threshold for slight nausea and irritation of the nose, throat, and chest from exposure to HC smoke with CT products of ZnCl₂ between 160 and 240 mg·min/m³. With CT products at 1,700 mg·min/m³ and above, effects can be severe and require hospitalization and treatment. Data from animals are sparse but indicate a NOAEL for HC smoke with ZnCl₂ at 26.6 mg/m³ in rodents for daily 1-hr exposures and a LOAEL for HC smoke with ZnCl₂ at 254 mg/m³ for inflammatory changes in the lung and death, suggesting a relatively steep dose-response curve.

HC smoke has been reported to produce alveolar carcinomas in mice. Fitting a generalized multistage linear dose-response model to those data provides an upper limit of the cancer risk of 0.086 per milligram ZnCl₂ per kilogram of body weight per day.

To establish EEGLs, the subcommittee used the CT product threshold of 160-mg.min/m³ for nausea and respiratory irritation in humans as an acceptable exposure level for short-term emergencies. Applying Haber's law to the CT product of 160 mg·min/m³, the 15-min EEGL is 10 mg/m³, the 1-hr EEGL is 3 mg/m³, and the 6-hr EEGL is 0.4 mg/m³ expressed as milligrams of ZnCl₂.

Virtually no human data are available to estimate a PEGL for HC smoke. Dividing the rodent NOAEL of 26.6 mg/m³ by an uncertainty factor of 10 to account for the shorter daily exposures of the test animals than of military personnel and by another uncertainty factor of 10 to account for interspecies differences in sensitivity, the subcommittee developed a PEGL of 0.2 mg/m³ for 8 hr per day, 5 days per week.

Because one study suggested that HC smoke is carcinogenic in mice, the subcommittee derived a cancer potency factor for HC smoke to determine whether its potential carcinogenicity required further attention. The subcommittee found that the possible cancer risks associated with the recommended EEGLs and PEGLs were approximately 1 in a million. Moreover, using actual air-concentration data from a real training facility and using unrealistic worst-case weather conditions, the subcommittee estimated risks to the community closely surrounding that facility to be less than 1 in a million.


EXPOSURE GUIDANCE LEVELS AT BOUNDARIES
OF MILITARY-TRAINING FACILITIES

The subcommittee developed SPEGLs and PPEGLs to ensure the protection of communities living near the facilities (Table S-2). In developing SPEGLs and PPEGLs, the subcommittee assumed that the general population includes sensitive subpopulations, such as the elderly, pregnant women, infants, children, and the chronically ill. In the absence of direct information on the toxicity of the smokes and obscurants in sensitive subpopulations, the subcommittee recommends that an uncertainty factor of 10 be used to extrapolate from guidance exposure levels derived for a population of healthy adults in the military to levels protective of more sensitive human subpopulations.

For all four obscurant smokes evaluated in this volume, the SPEGLs were estimated by dividing the EEGLs by an uncertainty factor of 10 to account for the likelihood of sensitive subpopulations in nearby communities. In addition, for all four smokes, the PPEGLs were estimated from the PEGLs and divided by an uncertainty factor of 10, again to account for the possibility that more sensitive subpopulations might reside near a military-training facility. Thus, all SPEGLs and PPEGLs in Table S-2 are 0.1 times the corresponding EEGLs and PEGLs in Table S-1.