A variety of smokes and obscurants have been developed and are used to screen armed forces from view, signal friendly forces, and mark positions. Obscurants are anthropogenic or naturally occurring particles suspended in the air that block or weaken transmission of particular parts of the electromagnetic spectrum, such as visible and infrared radiation or microwaves. Fog, mist, and dust are examples of natural obscurants. Smokes are produced by burning or vaporizing some product. Red phosphorus smoke and graphite smoke are examples of anthropogenic obscurants. The U.S. Army seeks to ensure that exposure to smokes and obscurants during training does not have adverse health effects on military personnel or civilians. 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 the toxicity of four obscuring smokes: white phosphorus, brass, titanium dioxide, and graphite. The results of the subcommittee's study are presented in this report, which is the second volume in the series. Toxicity data and exposure guidance levels for diesel-fuel, fog-oil, red phosphorus, and hexachloroethane smokes were presented in Volume 1. Seven colored smokes will be reviewed in a subsequent volume.

Contents

• Subcommittee on Military Smokes and Obscurants
• Committee on Toxicology
• Board on Environmental Studies and Toxicology
• Commission on Life Sciences
• Other Reports of the Board on Environmental Studies and Toxicology
• Other Reports of the Committee on Toxicology
• Preface
• List of Abbreviations
• Summary
• 1. Introduction
  • The Subcommittee's Task
  • Definitions of Exposure Guidance Levels
  • Approach to Developing Exposure Guidance Levels
  • Organization of the Report
  • References
• 2. White Phosphorus Smoke
  • Background Information
  • Toxicokinetics
  • Toxicity Summary: White Phosphorus And White Phosphorus Smoke
  • Previous Recommended Exposure Limits
  • Subcommittee Evaluation and Recommendations
  • Research Needs
  • References
• 3. Brass Smoke
  • Background Information
  • Previous Recommended Exposure Limits
  • Subcommittee Evaluation and Recommendations
  • Research Needs
  • References
• 4. Titanium Dioxide Smoke
  • Background Information
  • Toxicokinetics
  • Toxicity Summary
  • Previous Recommended Exposure Limits
  • Subcommittee Evaluation And Recommendations
  • Research Needs
  • References
• 5. Graphite Smoke
  • Background Information
  • Toxicokinetics
  • Toxicity Summary
  • Previous Recommended Exposure Limits
  • Subcommittee Evaluation and Recommendations
  • Research Needs
  • References

This project was supported by Contract Nos. DAMD 17-89-C-9086 and DAMD 17-99-C-9049 between the National Academy of Sciences and the U.S. Department of Defense. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project.

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 competencies and with regard for appropriate balance.

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce Alberts is president of the National Academy of Sciences.

The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. William A. Wulf is president of the National Academy of Engineering.

The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.

The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice chairman, respectively, of the National Research Council.