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Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants MAY 9 2008 THE GEORGE E. BROWN, JR. LIBRARY Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants Committee on Toxicology Board on Environmental Studies and Toxicology Commission on Life Sciences National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1992
NATIONAL ACADEMY PRESS 2101 Constitution Ave., N.W., Washington, D.C. 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 competencies 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. The National Academy of Sciences is a private, non-profit, 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. Frank Press 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. Robert M. White 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. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. The project was supported by the National Aeronautics and Space Administration under contract No. NASW-3749 and grant No. NAGW-2239. Additional copies of this report are available from the Board on Environmental Studies and Toxicology, 2101 Constitution Avenue, N.W., Washington, D.C. 20418 Printed in the United States of America TL1530.N375 1992 c. 1 Guidelines for developing spacecraft maximum allowable ... /
Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants DONALD E. GARDNER, Chairman, ManTech Environmental Technology, Inc., Research Triangle Park EULA BINGHAM, University of Cincinnati, Cincinnati JOSEPH BRADY, Johns Hopkins School of Medicine, Baltimore RICHARD BULL, Washington State University, Pullman CHARLES E. FEIGLEY, University of South Carolina, Columbia MARY ESTHER GAULDEN, University of Texas Southwestern Medical School, Dallas PAUL F. HALFPENNY, Engineering and Consulting, Van Nuys, CA WILLIAM E. HALPERIN, National Institute for Occupational Safety and Health, Cincinnati ROGENE F. HENDERSON, Lovelace Biomedical and Environmental Research Institute, Albuquerque MICHAEL HOLICK, Boston University School of Medicine, Boston E. MARSHALL JOHNSON, Thomas Jefferson Medical College, Philadelphia RALPH L. KODELL, National Center for Toxicological Research, Jefferson, AR DANIEL KREWSKI, Health and Welfare Canada, Ottawa, Ontario ROBERT SNYDER, Rutgers University, Piscataway KATHLEEN TAYLOR, General Motors Research Laboratories, Warren, MI BERNARD M. WAGNER, Wagner Associates, Inc., Millburn, NJ G. DONALD WHEDON, Shriners Hospitals for Crippled Children, Tampa Staff KULBIR S. BAKSHI, Project Director RICHARD D. THOMAS, COT Program Director MARVIN A. SCHNEIDERMAN, Senior Staff Scientist RUTH E. CROSSGROVE, Editor BEULAH S. BRESLER, Senior Editorial Assistant CATHERINE M. KUBIK, Senior Program Assistant in
Committee on Toxicology JOHN DOULL, Chairman, University of Kansas Medical Center, Kansas City EULA BINGHAM, Vice-Chairman, University of Cincinnati, Cincinnati R. HAYS BELL, Eastman Kodak Company, Rochester, NY DEAN E. CARTER, University of Arizona, Tucson CHARLES E. FEIGLEY, University of South Carolina, Columbia DONALD E. GARDNER, ManTech Environmental Technology, Inc., Research Triangle Park MARY ESTHER GAULDEN, University of Texas Southwestern Medical School, Dallas WALDERICO GENEROSO, Oak Ridge National Laboratory, Oak Ridge IAN GREAVES, University of Minnesota, Minneapolis RONALD A. KITES, Indiana University, Bloomington CAROLE A. KIMMEL, Environmental Protection Agency, Washington, DC RALPH L. KODELL, Food and Drug Administration, National Center for Toxicological Research, Jefferson, AR LOREN D. ROLLER, Oregon State University, Corvallis ERNEST EUGENE MCCONNELL, Raleigh, NC ROBERT SNYDER, Rutgers University, Piscataway BERNARD M. WAGNER, Wagner Associates, Inc., Millburn, NJ BAILUS WALKER, JR^ University of Oklahoma, Oklahoma City HANSPETER R. WITSCHI, University of California, Davis GAROLD S. YOST, University of Utah, Salt Lake City Staff RICHARD D. THOMAS, Program Director KULBIR S. BAKSHI, Senior Program Officer MARVIN A. SCHNEIDERMAN, Senior Staff Scientist BEULAH S. BRESLER, Senior Editorial Assistant CATHERINE M. KUBIK, Senior Program Assistant IV
Board on Environmental Studies and Toxicology PAUL G. RISSER, Chairman, University of New Mexico, Albuquerque FREDERICK R. ANDERSON, Cadwalader, Wickersham & Taft, Washington, DC JOHN C. BAILAR in, McGill University, Faculty of Medicine, Montreal LAWRENCE W. BARNTHOUSE, Oak Ridge National Laboratory, Oak Ridge GARRY D. BREWER, University of Michigan, Ann Arbor EDWIN H. CLARK, Department of Natural Resources & Environmental Control, State of Delaware, Dover YORAM COHEN, University of California, Los Angeles JOHN L. EMMERSON, Lilly Research Laboratories, Greenfield, IN ROBERT L. HARNESS, Monsanto Agricultural Company, St. Louis ALFRED G. KNUDSON, Fox Chase Cancer Center, Philadelphia GENE E. LIKENS, The New York Botanical Garden, Millbrook PAUL J. LJOY, UMDNJ-Robert Wood Johnson Medical School, Piscataway JANE LUBCHENCO, Oregon State University, Corvallis DONALD MATTISON, University of Pittsburgh, Pittsburgh GORDON ORIANS, University of Washington, Seattle NATHANIEL REED, Hobe Sound, FL MARGARET M. SEMINARIO, AFL/CIO, Washington, DC I. GLENN SIPES, University of Arizona, Tucson WALTER J. WEBER, JR^ University of Michigan, Ann Arbor Staff JAMES J. REISA, Director DAVID J. POLICANSKY, Associate Director and Program Director for Natural Resources and Applied Ecology RICHARD D. THOMAS, Associate Director and Program Director for Human 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 BRUCE M. ALBERTS, Chairman, University of California, San Francisco BRUCE N. AMES, University of California, Berkeley J. MICHAEL BISHOP, University of California Medical Center, San Francisco MICHAEL T. CLEGG, University of California, Riverside GLENN A. CROSBY, Washington State University, Pullman LEROY E. HOOD, California Institute of Technology, Pasadena DONALD F. HORNIG, Harvard School of Public Health, Boston MARIAN E. KOSHLAND, University of California, Berkeley RICHARD E. LENSKI, Michigan State University, East Lansing STEVEN P. PARES, University of Texas, Dallas EMIL A. PFTTZER, Hoffmann-LaRoche, Inc., Nutley, NJ THOMAS D. POLLARD, Johns Hopkins Medical School, Baltimore JOSEPH E. RALL, National Institutes of Health, Bethesda, MD RICHARD D. REMINGTON, University of Iowa, Iowa City PAUL G. RISSER, University of New Mexico, Albuquerque HAROLD M. SCHMECK, JR, Armonk, NY RICHARD B. SETLOW, Brookhaven National Laboratory, Upton, NY CARLA J. SHATZ, University of California, Berkeley TORSTEN N. WIESEL, Rockefeller University, New York JOHN E. BURRIS, Executive Director
Acknowledgments The Committee on Toxicology's Subcommittee on Spacecraft Maximum Allowable Concentrations for Space Station Contaminants gratefully acknowledges the valuable assistance provided by the following personnel from the National Aeronautics and Space Administration (NASA) and its contractors: Dr. John James (NASA) Dr. Duane Pierson (NASA) Dr. Martin Coleman (NASA) Dr. Lawrence Dietlein (NASA) Mr. Jay Perry (NASA) Mr. Kenneth Mitchell (NASA) Mr. James Hyde (Jet Propulsion Laboratory) Dr. King Lit Wong (Krug International) Mr. Donald Cameron (Boeing Company) The subcommittee also acknowledges the valuable assistance provided by the Johnson Space Center, Houston, Texas, the Marshall Space Flight Center, Huntsville, Alabama, the Kennedy Space Center, Cape Canaveral, Florida, and the Space Station Freedom Program Office, Reston, Virginia, for providing tours of their facilities. The subcommittee is grateful to astronauts Dr. Shannon Lucid and Dr. Drew Gaffney for sharing their experiences. vii
Preface The National Aeronautics and Space Administration (NASA) has been concerned with the potential toxicological hazards to humans that may be associated with entering and living within spacecraft for pro- longed periods. Despite major engineering advances in controlling the atmosphere within spacecraft, some contamination of the air appears inevitable. NASA has responded to this problem by measuring and identifying numerous airborne contaminants during each space mis- sion. As space missions increase in duration and complexity, ensuring the health and well-being of individuals traveling and working in this unique environment becomes increasingly uncertain. As part of its attempt to establish a safe space environment, NASA has requested that the National Research Council's Committee on Toxicology (COT) develop appropriate guidelines for establishing spacecraft maximum allowable concentrations (SMACs) for space- station contaminants. SMACs are not intended to represent the absolute dividing line between safe and unsafe exposures, because certain individuals may respond differently. Short-term SMACs provide guidance for crew members when it becomes necessary to operate under emergency conditions lasting up to 24 hr. Such exposures may produce measurable, but reversible, responses and discomfort, but they should not interfere with or impair judgment. Long-term SMACs are intended to avoid adverse health effects, immediate and delayed, and to avoid degradation in performance from continuous exposure. In response to NASA's request, COT established the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants. This subcommittee was made up of scientists with expertise in toxicology, biochemistry, epidemiology, pathology, analytical chemistry, industrial hygiene, genetics, occupational medicine, biostatistics, and risk assessment. ix
X PREFACE In establishing these guidelines, several major issues were con- sidered, including the development of methods for (1) translating existing animal toxicity data to predict toxicity for humans in space, (2) evaluating the toxicity of complex mixtures, (3) modifying risk estimates to account for altered physiological changes and stresses caused by the microgravity environment of space, and (4) determining how other exposure conditions within the spacecraft, such as recirculation of air and water, lack of purging of expired air, activities outside the space station, contamination from airlocks, reentry, and radiation, may alter the predicted or expected response. The subcommittee recognizes that many factors, such as the altera- tions in normal human physiological and biochemical processes associ- ated with spaceflight, are not fully understood and could warrant revisions of proposed SMAC values. The subcommittee emphasizes the necessity to review continuously and adjust these values when additional scientific data become available. This report could not have been produced without the untiring efforts of the National Research Council staff: Beulah Bresler, senior editorial assistant; Catherine Kubik, senior program assistant; and Ruth E. Crossgrove, editor. Finally, the subcommittee gratefully acknowledges the persistence, patience, and expertise of Dr. Kulbir S. Bakshi, project director of the subcommittee, and Dr. Richard D. Thomas, program director of COT, in bringing this report to its final form. Donald E. Gardner, Chairman Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants John Doull, Chairman, Committee on Toxicology
Contents LIST OF ABBREVIATIONS xiii EXECUTIVE SUMMARY 1 1 INTRODUCTION 9 2 HISTORICAL DEVELOPMENT OF LIMITS FOR TOXICANTS IN SPACECRAFT 13 3 SOURCES OF SPACE-STATION CONTAMINANTS 23 4 ENVIRONMENTAL CONTROL AND LIFE-SUPPORT SYSTEM 41 Contaminant Control and Monitoring 42 Recommendations 44 5 PHYSIOLOGICAL CHANGES DURING SPACEFLIGHT 49 Space Motion Sickness 49 Bone and Mineral Metabolism 50 Muscle Metabolism 53 Cardiovascular Function and Body Fluid Changes 54 Immune System 55 Nutrition 55 6 ESTABLISHMENT OF SPACECRAFT MAXIMUM ALLOWABLE CONCENTRATIONS 59 Description of SMACs 59 Sources of Data for Developing SMACs 60 Types of Data Used in Recommending SMACs 64 Risk Assessment 78 General Approach to Establishing SMACs 94 XI
xii CONTENTS REFERENCES 97 APPENDIX 1 Format for SMAC Documents 109 APPENDIX 2 Conversion Factors 111 APPENDIX 3 Reference Values Used by COT 113
List of Abbreviations ACGIH American Conference of Governmental Industrial Hygienists ACMA Atmospheric composition monitor assembly ACS Atmosphere control and supply AD Aerodynamic diameter ADI Acceptable daily intake ALARA As low as reasonably achievable ARS Atmosphere revitalization subsystem ATSDR Agency for Toxic Substances and Disease Registry BEST Board on Environmental Studies and Toxicology CEGL Continuous exposure guidance level CNS Central nervous system COT Committee on Toxicology ECLSS Environmental control and life-support system EEGL Emergency exposure guidance level EEL Emergency exposure limit EPA Environmental Protection Agency FAA Federal Aviation Administration FDS Fire detection and suppression IRIS Integrated Risk Information System LOAEL Lowest-observed-adverse-effect level MCA Major constituent analyzer MF Modifying factor NASA National Aeronautics and Space Administration NIOSH National Institute for Occupational Safety and Health NOAEL No-observed-adverse-effect level NOEL No-observed-effect level NRC National Research Council OSHA Occupational Safety and Health Administration PEL Permissible exposure limit PMC Permanently manned capability RDA Recommended Dietary Allowance xiii
JCI> LIST OF ABBREVIATIONS REL Recommended exposure limit RfC Reference concentration RfD Reference dose SF Safety factor SMAC Spacecraft maximum allowable concentration SMS Space motion sickness STEL Short-term exposure limit TCCS Trace contaminant control subassembly THC Temperature and humidity control TLV Threshold limit value UF Uncertainty factor WM Waste management WRM Water recovery and management
