INDUSTRIAL HYGIENE CHEMICAL VAPOR TECHNICAL BASIS The Industrial Hygiene Technical Basis purpose is

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  • RPP-22491 Revision 1

    INDUSTRIAL HYGIENE

    CHEMICAL VAPOR

    TECHNICAL BASIS

    Prepared for the U.S. Department of Energy Assistant Secretary for Environmental Management Contractor for the U.S. Department of Energy Office of River Protection under Contract DE-AC27-99RL14047

    P.O. Box 1500 Richland, Washington

  • RPP-22491 Revision 1

    INDUSTRIAL HYGIENE CHEMICAL

    VAPOR TECHNICAL BASIS

    J. E. Meacham J. O. Honeyman T. J. Anderson M. L. Zabel CH2M HILL Hanford Group, Inc. J. L. Huckaby Pacific Northwest National Laboratory Date Published May 2006 Prepared for the U.S. Department of Energy Assistant Secretary for Environmental Management Contractor for the U.S. Department of Energy Office of River Protection under Contract DE-AC27-99RL14047

    P.O. Box 1500 Richland, Washington

  • RPP-22491 Revision 1

    TRADEMARK DISCLAIMER Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors.

    This report has been reproduced from the best available copy.

    Printed in the United States of America

  • RPP-22491 Rev. 1

    iii

    EXECUTIVE SUMMARY The Industrial Hygiene Technical Basis purpose is to identify all chemicals within a waste vapor source (i.e., tank headspaces, ventilation stacks and the 242-A Evaporator) that are potentially hazardous and might be released into worker breathing zones. It provides the Industrial Hygiene program with the basis to make decisions and set controls that ensure worker protection. The approach assesses gases and vapors generated by ongoing waste decomposition, release mechanisms from the waste to tank headspaces, behavior of gases and vapors in tank headspaces, discharges of the headspace atmosphere through breather filters and stacks to the environment, and environmental effects on chemical vapor concentrations. CH2M HILL Hanford Group, Inc. technical expertise was augmented with tank chemistry and toxicology experts. An Independent Toxicological Panel of nationally recognized toxicology and industrial hygiene experts reviewed and validated the methodology used and particularly, the toxicological basis for preparation of the Chemicals of Potential Concern (COPC) list. Headspace gas and vapor origins are understood and can be related back to chemicals placed into tanks and their degradation chemistry. Concentrations are determined by dynamic competition between evolution from the waste and removal by ventilation or other means. Absent waste-disturbing activities, changes are slow, and there are no large, rapid changes in headspace concentrations. Headspace concentrations do vary over months and years, but sampling results indicate that 95% of the chemicals in a passively-ventilated single-shell tank (SST) vary by less than a factor of three. Most SST headspaces have been sampled (118 of 149), and similarities between sampled tanks suggest that the non-sampled SSTs have similar compositions. Headspace characterization provides a large body of information about the identities and concentrations of the waste gases and vapors. Sampling and analyses have progressed sufficiently to identify and evaluate a broad range of chemicals. Characterization data maintained in the Tank Characterization Database (TCD) are based on appropriate sampling and analytical methods, and these data were used to identify chemical species and estimate concentrations to be expected in tank headspaces. Headspace gases are released via breather filters and other penetrations in tanks and might enter worker breathing zones. Dispersion modeling indicates that SST headspace and double-shell tank stack chemical concentrations would be diluted up to several orders of magnitude after traveling five or more feet from the source. Worker breathing zone data (area samples and personal monitoring) indicate that gas and vapor concentrations are orders of magnitude lower than concentrations found in tank headspaces, consistent with the dispersion modeling results. Most tank headspace chemicals present in the worker breathing zones are below sampling and analytical detection limits and those chemicals that have been detected are well below occupational exposure limits. Sampling and analytical detection limits are established by evaluating the Occupational Exposure Limits for those chemicals that might be present in the workplace to provide assurance that all hazardous or potentially hazardous chemicals would be detected if present.

  • RPP-22491 Rev. 1

    iv

    Volatile waste chemicals were evaluated for their potential hazard to workers. The evaluation was comprehensive and addressed all chemicals reported in tank headspace and ventilation system samples, volatile chemicals reported in liquid and solid waste samples, and chemicals identified as potentially present in the tank headspaces but not reported because of sampling and/or analytical limitations. Forty-eight chemicals have been detected at tank farm sources at greater than 10% of the Occupational Safety & Health Administration Permissible Exposure Limits, American Conference of Governmental Industrial Hygienists Threshold Limit Values, or Hanford Site Tank Farms Acceptable Occupational Exposure Levels were placed on the COPC list.

  • RPP-22491 Rev. 1

    v

    CONTENTS

    1.0 INTRODUCTION ...............................................................................................................1

    1.1 PURPOSE................................................................................................................1 1.2 BACKGROUND .....................................................................................................2 1.3 CONCLUSIONS......................................................................................................3

    2.0 GAS AND VAPOR SOURCES AND DYNAMICS ..........................................................4

    2.1 GAS AND VAPOR SOURCES ..............................................................................4 2.1.1 Process Wastes.............................................................................................4 2.1.2 Chemical Generation and Storage ...............................................................5 2.1.3 Other Chemicals...........................................................................................7

    2.2 TRANSPORT AND RELEASE MECHANISMS ..................................................7 2.3 HEADSPACE DYNAMICS....................................................................................9 2.4 242-A EVAPORATOR .........................................................................................10 2.5 CONCLUSIONS....................................................................................................11

    3.0 MEASURED AND PROJECTED HEADSPACE COMPOSITIONS..............................13

    3.1 VAPOR SAMPLING BASICS..............................................................................13 3.2 SAMPLING MEDIA AND ANALYSIS METHODS ..........................................14

    3.2.1 SUMMA Canister Samples........................................................................15 3.2.2 Sorbent Trap Samples ................................................................................16 3.2.3 Metals Sampling ........................................................................................16

    3.3 SOURCE SAMPLING DATA SUMMARY ........................................................17 3.4 HEADSPACE VARIABILITY .............................................................................19 3.5 EFFECTS OF WASTE-DISTURBING ACTIVITIES .........................................21 3.6 CONCLUSIONS....................................................................................................22

    4.0 WASTE GASES AND VAPORS IN THE WORKER BREATHING ZONE..................23

    4.1 ACTIVE VENTILATION.....................................................................................23 4.2 PASSIVE VENTILATION ...................................................................................23 4.3 ATMOSPHERIC DISPERSION OF RELEASES ................................................25 4.4 CORRELATION BETWEEN VAPOR INCIDENTS AND

    METEOROLOGICAL CONDITIONS .................................................................27 4.5 INDUSTRIAL HYGIENE SOURCE, AREA AND PERSONAL DATA............27

    4.5.1 Data from 1992 through 2003....................................................................28 4.5.2 Data from 2004 through 2006....................................................................29

    4.6 CONCLUSIONS....................................................................................................31

    5.0 TOXICOLOGICAL EVALUATION................................................................................33

    5.1 VOLATILE TANK WASTE CHEMICALS.........................................................33 5.2 CHEMICALS ........................................................................................................33

    5.2.1 Misidentified Chemicals ............................................................................34 5.2.2 Contaminants .............................................................................................3