Control Technology Assessment: Metal Plating and Cleaning ...

1 TECHNICAL REPORT Control Technology assessment : Metal Plating and Cleaning Operations DEPARTMENT OF HeAL HI AND HUMAN SERVICES Public Health Service centers for Disease Control National Institute for Occupational Safety and Health NIOSH TECHNICAL REPORT Control Technology assessment : Metal Plating AND Cleaning OPERATIONS John W. Sheehy Vincent D. Mortimer James H. Jones Stephanie E. Spottswood U. S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service Centers for Disease Control National Institute for Occupational Safety and Health Division of Physical Sciences and Engineering Cincinnati, Ohio 45226 December 1984 For aale by the of Documents. Government Printing Offlet', Washington, 20402 -/-()." DISCLAIMER Mention of company names or products does not constitute endorsement by the National Institute for Occupational Safety and Health (NIOSH).

2 DHHS (NIOSH) Publication No. 85-102 ii ABSTRACT A Control Technology assessment of electroplating and Cleaning operations was conducted by the National Institute for Occupational Safety and Health (NIOSH). Walk-through surveys were conducted at about 30 electroplating plants and 9 in-depth studies at 8 plants. Air sampling and ventilation data and other Control information were collected for 64 Plating and Cleaning tanks. Thirty-one of these were hard chrome Plating tanks but cadmium, copper, nickel , silver, and zinc Plating tanks were also evaluated. Acid, caustic and solvent Cleaning tanks were also evaluated. Worker exposures were found to be controlled below existing and recommended standards. i11 I. II. III. IV. V. VI. VII. VIII. ABSTRACT ACKNOWLEDGEMENTS INTRODUCTION Metal Plating INDUSTRY Mechanical Processes Bath Composition Cleaning Tanks Electroplating Baths HEALTH HAZARD ANALYSIS CONTENTS Overview of Chromium Health Effects Acids, Alkalies, and Solvents Metals and Salts LITERATURE REVIEW OF Plating PROCESS CONTROLS STUDY METHODS Ai r Sampling Airflow Measurements RESULTS Engineering Controls Hard Chromium Plating Reverse Chromium Stripping Silver Plating Copper Plating nickel Plating Cadmium Plating Zinc Plating Acid Cleaning Caustic Cleaning Solvent Degreasing Work Practices Personal Protective Equipment Hygiene Procedures Monitoring CONCLUSIONS AND RECOMMENDATIONS REFERENCES APPENDIX A.

3 Sampling Results iv iii ix 1 3 3 4 4 6 11 11 16 18 20 26 26 30 32 32 32 58 58 62 65 67 70 73 80 82 84 87 88 88 90 92 97 LIST OF TABLES Table 1-1 Types of Plating or Cleaning baths encountered in study 2-1 Summary of contaminants which may be released from typical 2-2 2-3 3-1 5-1 6-1 6-2 pre-treatment processes Summary of contaminants which may be released from typical Plating processes Cathode operating conditions Hazardous substances from electroplating processes Sampling and analytical methods Range of values for selected Plating tank parameters Relationship of Plating load and tank emissions for one tank 6-3 Airflow measurements for hard chromium tanks with push-pull ventilation . 6-4 Average concentrations around tanks with push-pull ventilation 6-5 Selected plant data and average tank-area concentrations for hexavalent chromium compared to average general air concentrations 6-6 Silver tank parameters 6-7 Air sampling results -silver Plating 6-8 Copper Plating tank parameters 6-9 Air sampling results -copper Plating 6-10 nickel Plating parameters 6-11 Air sampling results - nickel Plating .

4 6-12 Cadmium Plating parameters 6-13 Air sampling results -cadmium Plating 6-14 Air sampling results -zinc Plating 6-15 Acid Cleaning tank parameters 6-16 Air sampling results -acid tanks v .. 2 5 7 8 16 27 33 38 51 55 56 59 60 62 63 66 67 68 69 73 74 77 Table 6-17 6-18 6-19 6-20 A-I A-2 A-3 LIST OF TABLES (cont'd) Personal air sampling results -acid tanks Caustic Cleaning tank parameters Air sampling results -caustic tanks Air sampling results -tetrachloroethylene degreaser tank Personal sample statistics Tank-area sample statistics General-area sample statistics vi Page 78 80 82 83 98 101 106 Figure 6-1 6-2 6-3 6-4 6-5 6-6 6-7 6-8 6-9 6-10 6-11 6-12 6-13 6-14 6-15 LIST OF FIGURES Hardchrome Plating tank with two-sided ventilation Hardchrome Plating tank with two-sided ventilation Hardchrome Plating tank with two-sided ventilation Hardchrome tank with two-sided ventilation Tank -three-sided ventilation.

5 Average hexavalent chromium concentrations with respect to exhaust rate for all chromium tanks compared to pertinent ceiling limits .. Average hexavalent chromium concentrations with respect to exhaust rate for uncovered tanks with ventilation on two sides Average total chromium concentrations with respect to exhaust rate for uncovered tanks with ventilation on two sides Average hexavalent chromium concentrations with respect to exhaust rate divided by the ventilation Control distance for uncovered tanks with ventilation on two sides Average hexavalent chromiun concentrations with respect to exhaust rate for uncovered tanks with ventilation on one or three sides compared to representative curves for two-sided ventilation .. Average hexavalent chromium concentrations with respect to exhaust rate divided by the ventilation Control distance for uncovered tanks with ventilation on one or three sides compared to representative curves for two-sided ventilation Effect of full and partial covers on controlled airflow for a tank with two-sided ventilation Average hexavalent chromium concentrations with respect to exhaust for covered tanks compared to representative curves for uncovered two-sided ventilation Average hexavalent chromium concentrations with respect to exhaust rate provided by ventilation Control distance for covered tanks with ventilation on one or three sides compared to representative curves for uncovered

6 Two-sided ventilation Average hexavalent chromium concentrations with respect to exhaust rate for one tank with and without a cover compared to pertinent ceiling limits vii Page 34 34 35 36 37 38 40 41 43 44 45 47 48 49 50 Figure 6-16 6-17 6-18 6-19 6-20 6-21 6-22 6-23 6-24 6-25 6-26 6-27 6-28 6-29 LIST OF FIGURES Hard chrome Plating tanks with push-pull ventilation Tanks A and B with covers and push-pull ventilation Schematic of tank with push-pull ventilation Average hexavalent chromium exhaust rate for tanks with to pertinent ceiling limits concentrations with respect to push-pull ventilation compared .. Silver Plating tank 1D Copper Plating tank, IF Cadmium Plating tank -ventilated Zinc automatic rack Plating line Zinc Plating tank.

7 Acid Cleaning line and exhaust hood Side view of acid hood and tank Tank 7H -acid etch .. Caustic Cleaning tank with cover .. Solvent degreaser with cover open viii 52 53 53 54 61 64 68 71 72 75 75 76 81 83 ACKNOWLEDGEMENTS The authors would like to acknowledge the assistance of Alfred A. Amendola, Mary Ellen Cassinelli, Alex Cohen, Peter M. Eller, John C. Frede, Frank W. Godbey, Robert T. Hughes, Donald E. Hurley, Daniel R. Kemme, Sharon L. Kercher, Kenneth F. Martinez, Dennis M. O'Brien, Vernon Putz-Andersen, David E. Schroer, Kenneth M. Wallingford, and Ruby Watson of NIOSH during the field surveys conducted for this study. Mary Ellen Cassinelli of NIOSH or the Utah Biomedical Test Laboratory performed all air sample analysis required for the study.

8 Stanley A. Shulman provided invalu,able _ assistance with statistical analysis of data collected during the study. Rosalynd J. Kendall was extremely helpful in providing editorial comments on the manuscript. We also wish to recognize the interest and assistance of Mr. King Ruhly, Executive Director, Metal Finishing Suppliers Association. ix I. INTRODUCTION As a result of the Occupational Safety and Health Act of 1970 (PL 91-596), the National Institute for Occupational Safety and Health (NIOSH) has instituted a major program to prevent occupational health problems through the application of Control Technology in the workplace. The goal of this program is to stimulate private industry to prevent hazardous exposures to workers and to document successful approaches and applications of Control measures.

9 The Plating and Cleaning ( Metal finishing) industry was selected for a Control Technology assessment study because of the use of substances that are recognized health hazards such as hexavalent chromium, sulfuric acid, and cyanide. A large number of Plating and Cleaning shops involve manual operations such as dipping and masking where potential exposure to hazardous substances is high. In addition, a major portion of the Plating and Cleaning industry are small businesses, lacking the resources to develop information on the prevention of excessive occupational exposure on their own. The study was performed through a review of the technical literature on Plating processes and equipment and their associated hazards; preliminary surveys of approximately 30 electroplating plants, and 9 in-depth surveys at B electroplating plants.

10 Preliminary surveys were conducted to further identify Control methods, select plant locations for in-depth surveys, and to finalize sampling protocol. The in-depth surveys consisted of industrial hygiene measurements of selected hazards, engineering evaluation, and documentation of Control methods. The in-depth survey sites, their Plating and Cleaning baths, and the associated hazards are presented in Table 1-1. This report examines Control methods and systems for specific Plating baths and Cleaning solutions such as chromic acid, cadmium, cyanide and mixed acid cleaners. Sixty-four Plating and Cleaning tanks were evaluated with the major emphasis on hard chromium Plating . Individual plant reports which include more detailed information on specific plant processes and controls are available from the National Technical Information Service*.