Document jy2b9zr9d2B2o21vVzjoB0VbR

FILE NAME DuPont DUP DATE 1969 Nov 1 DOC DUP202 DOCUMENT DESCRIPTION Report - Old Hickory Textile Fibers - Asbestos Dust Control ASBESTOS DUST CONTROL CONTROL CONTROL DUP 1012406 DU 053453 ASBESTOS DUST CONTROL e a 1 Old Hickory Textile Fibers Old Hickory Tennessee November , 1969 DUP 1012407 DU 053454 ASBESTOS DUST CONTROL This summary report is a compilation of work done by Analytical Research Laboratory Chemical Control Laboratory and Works Engineering Section Old Hickory Textile Fibers Old Hickory Tennessee By R. E. Tyree Area Engineer Maintenance Engineering DUP 1012408 DU 053455 TABLE OF CONTENTS INTRODUCTION . . e . e e e e DEVELOPMENT OF OLD HICKORY'S ASBESTOS DUST EXPOSURE LIMITS THRESHOLD LIMIT VALUES SAMPLING PROCEDURE SAMPLE DATA .., RECOMMENDATIONS SUMMARY .... ACKNOWLEDGMENTS APPENDIXES Page No. DUP 1012409 DU 053456 I. Introduction A. Objectives Reference Letter J. H. Sigman Cox to R. J. Blair 8/8/68 Letter R. J. Blair to O. W. Hess 8/16/68 See Appendix A 1 Study jobs where asbestos dust is present take dust samples for analysis and determine when protection is required respiratory 2 Provide information to the Textile Fibers that could be used Department as a guide for a uniform safely standard 3 Recommend minimum equipment requirements for dust control adequate Premise 1. Asbestos dust control is the prevention of high concen- trations of asbestos dust entering the lung of asbestos workers insulators and any other person handling or working with asbestos exposed to 2- Asbestosis is a fibrogenic scar producing pneumo- coniosis dust disease of the lung due to inhalation of asbestos fiber dust In its it more advanced stages can impair respiratory fufunnction ction with production of emphysema Total disability and Especially in smokers there is a marked increase in incidence of several varieties of cancer There is no known cure for asbestosis therefore every reasonable effort be made from a to humane standpoint control the dust and prevent it from lung entering the DUP 1012410 DU 053457 II Development of Old Hickory's Threshold Limit Values Asbestos Dust Exposure Limits In April 1968 the Engineering Department's Construction Division established procedures for monitoring air using personnel air sampling instruments see Appendix B Samples were then sent to the University of Pittsburgh for microscopy analysis by qualified experts The Construction Division's established Threshold Limit Value TLV for total dust count at this time was set particles per cubic foot of air for industry This was 1/10 at 500,000 the TLV set Old Hickory's Asbestos Committee of asbestos dust and control and studies has has researched the concluded from subject their Asbestos dust consisted of grains and fibers 1 The fibers are the major recognized health hazard Large dust grains studies show that do enter the lung cannot enter the lungs but medical long fibers as long as 200 microns and cause asbestosis 2 @ Prior to 1960 exposure measurements were based on particle counting methods which were not efficient for TLV fiber count had been set Therefore by necessity the asbestos for dust concentrations which were measured primarily by grain count @e In the late 1950's new sample and count techniques were developed which provided much improvement in the accuracy and efficiency of counting asbestos dust grains and fibers This method was particularly effective in the fiber sizes of most concern i.e. 5 microns and greater length 1 Fiber is defined as any particle having a size ratio of 3 to 1 or greater to diameter 2 1 micron = approximately .00004 inches DUP 1012411 DU 053458 f e Studies since that time led the American Conference of Governmental Industrial Hygienists in 1968 to adopt as an intent to change 1 " , a TLV of 12 fibers greater than 5 microns in length per milliliter of air 12 fibers 5 ...or 2 million particles per cubic foot of air 2 MPPCF instead of the present TLV of 5 MPPCF see Appendix C The 12 fibers > 5 TLV is based on the new membrane filter sample method whereas the 2 MPPCF TLV is based on the older less effective impinger sample method @ Both the ACGIH and the Division of Occupational Health Department of Health Education and Welfare agree the fiber count method will in all probability replace particulate measurement for exposure to asbestos dust and will be in the TLV Recommended category in 1970 e The Construction Division's TLV and the Departmental goal of 500,000 PPCF actually applies to overall dustiness as measured by the impinger method and is not meaningful when the sample is taken by the membrane filter method The membrane filter remains the best method of measurement to date and justities its continued use findings sampling was being findings the fact that membrane filter used used used at Old Hickory Hickory the committee agreed to change from the Departmental TLV goal of 500,000 PPCF to 12 fibers > 5 ~ in length for instantaneous or short term exposure one hour or less A length >5 in This is 1/2 the was established for ACGIH proposed TLV eight We TLV of 6 fibers hour exposure feel that TLV goals of 12 and 6 offer as much or more protection than the original TLV expressed in particles Additionally we are aligning ourselves in the direction which the asbestos industry and those in the field of study are taking We shall continue to take additional dust samples and follow the industry studies 1 The ACGIH leaves their recommendation in a Notice of Intended Change category for two years If in two years questioning the values in the Recommended list no evidence comes to light TLV's they are then placed 2 The ACGIH TLV of 12 fibers based on an hour day > 5 is a time weighted average DUP 1012412 DU 053459 III In the following sample data Old Hickory used for long and short term exposure defined above ing when respiratory protection is required the for TLV's specify- Sampling Procedure IV Sampling at Old No. 92814 with Aerosol Adaptor Hickory was done with an MSA portable pump Millipore Filter Assembly No. MAWG037AO and No. XX6200004 All samples were sent to Dr. Morton Corn Attention Felix Stein Department of Occupational Health University of Pittsburgh Pittsburgh Pennsylvania 15213 Dr. Corn is a qualified analysis See Appendix expert in the field for microscopy D for actual procedures Sample Data In a period May through August 43 samples were taken and analyzed See Appendix E Of the 43 36 were jobs 7 were sampled at vents Fifteen of the 36 were out of limits Four or the 15 out sawing Unibestos one long term of limits were taken whiie machine There were three short term samples and Of the 11 remaining 5 were greater than samples 6 samples samples 6 six hours were less than one hour and Following are data of the 15 samples that exceeded TLV's DUP 1012413 DU 053460 ( ) DUST SAMPLING EXCEEDING TLV's - 278 weet gates . Instantaneous or short term hour > 5 length Long term eight hour > 5 length or less average Duration Fiber Sample No. Location and Activity of Sample ML > 5 wit - 12 fibers - fibers Remarks Group 1 25 Central Shops - 20 min Sawing Unibestos 28 Central Shops - 5 min Sawing Unibestos 477 _ 99 Sawing of Unibestos All samples produced fiber counts greatly exceeding TLV's 30 Central Shops - 10 min Sawing Unibestos 759 32 Reemay Shop - 1 hr Sawing Unibestos 4 min and Kaylo 249 Central Shops - Sawing Dacron Shops - Sample B - Sawing Ruberoid 10 min 15 min Dacron Shops Sawing & Pouring Ground Asbestos 13 min 42 Dacron Shops - Sawing Kaylo 7 hr 30 min 19 DMT Shop - Sawing 15 min 25 DMT Shop - Sawing 10 min Asbestos Without Bag Over Exhaust 15 PRL Shop - Sawing 16 min With Vacuum on Saw 38 27 : . 38 Sawing of Insulation Specific brands of insulation not known All short term fiber counts exceed TLV by considerable amount The long term sample 42 only slightly exceeds TLV 8 925 773 106 DUP 1012414 DU 053461 DUST SAMPLING EXCEEDING TLV's Cont'd Sample No. Location and Activity Duration of Sample Fiber ML > 5 Remarks Group 3 39 Central Shops - 7 hr Routine Work 40 Dacron Shops - 6 hr Routine Work ; 4 min 7 Routine Long Term Work includes all types of jobs from sawing to 13 cleaning Some read- ings are slightly . . 41 Dacron Shop 6 hr greater than two times - 8 the TLV but do not Routine Work 10 min approach the levels of 42 Power Maintenance 6 hr the short term jobs 13 Routine Work 50 min V. Recommendations Based on Old Hickory's study of the asbestos dust problem and analysis of the sample data the following recommenda- tions are made 1. rs The Engineering Standards should specify the exclusion of insulation materials containing Crocidolite type CK Use of Unibestos be discontinued and removed from the Ck Engineering Department Standards Samples should be taken using membrane filters instead OK of impinger type samplers at several plant locations ~ Torit Dust Collector Series 19 or equal should be NO specified for use on all power saws used for asbestos Consider including in Engineering Standards All existing vacuum systems used for asbestos dust removal should be upgraded to highest effectiveness attainable against air leakage Special attention should be given to bandsaws Consider including in Engineering Standards " fl fl 1 Analyze data to establish relationship to the TLV This may indicate relaxing or tightening of requirements Routine sampling should be done so that dust level control can be maintained DUP 1012415 ~ DU 053462 6. Torit Down Draft Benches or equal should be specified for use in production type insulation shops where severe dusting occurs from shaping asbestos OME 1.5M- cutting or handsawing Consider including in Engineering Standards 7 Approved vacuum cleaners shall be used for floors equip- ment etc. whenever practical Investigation is continu- ing to find vacuum cleaners that will entrap particle sizes 5 microns and greater efficiently Goal is to reduce fiber content of the exhaust air 8. Minimum Safety Rules a Mineral dust respirators approved under U. S. Bureau of Mines Schedule 21B life Appendix F shall be worn for the following jobs life 1 All sawing of Unibestos until this product is discontinued 2 Pouring of ground asbestos in all cases Examples filling storage bins dumping into mix pails etc. 3 Tearing off asbestos insulation from pipelines equipment vessels etc. 4 Any operation involving cleaning or removing of asbestos dust or residue in which an approved vacuum cleaner is not used (5 ) ) Cleaning vacuum systems and vacuum cleaners handling asbestos dust b An approved vacuum cleaner shall be used to remove asbestos dust when cleaning floors equipment and parts wherever practical Where impractical an approved dust mask shall be worn c On power equipment provided with dust removal systems turn systems on before working on asbestos materials Turn systems off only after completing work old Hickory has chosen 96042 filter approved the MSA Dustfoe under 21B as a 77 with catalog number plant standard The Insulation Industry Hygiene Research Program and Manville Research and Engineering Center are developing and testing disposable masks with the cooperation of members of the Inter- national Workers Association Heat and Frost Insulators and Asbestos Old Hickory will keep Textile Fibers informed on this development DUP 1012416 DU 053463 Procedures All insulation shops must be properly ventilated and saws equipped with high efficiency cyclone type or fabric filter type dust collectors In order to assure expedient and efficient dust removal the following shall be in effect a Specific Safety Rules shall apply b Equipment and shops shall be inspected once per month to assure systems are being maintained and are operating properly This inspection shall be on the IBM monthly reminder Specific items to be checked are 1 Dust collector fans operating 2 Seals around ducts are tight to assure adequate velocity and volume of air 3 All duct joints are tight 4 Dust collection containers shall have plastic bags inserted to eliminate need for shoveling sweeping dumping etc. Bags should not be allowed to fill more than 1/2 to 2/3 full to allow for tying the tops of bags upon removal to prevent dusting condition 5 Under normal use of saws average one hour sawing per day the cloth exhaust filter bags should be agitated shaken and beaten each week and cleaned each six months 6 To clean exhaust filter bags a large plastic should be placed over the filter bag and tied the top Then with the fan off agitate the bag at filter bag vigorously by beating and shaking to loosen the dust particles from inside and outside the filter bag Plastic bag must then be removed tied and disposed of Dust inside the filter bag will settle to the bottom These bags can be used indefinitely by properly cleaning but it is recommended they be replaced after three years normal use DUP 1012417 DU 053464 7 Ducts shall be checked by use of flashlight or other means to assure they are not plugged 8 Room exhausts and wall fans shall be proper rotation of fan and grids are not blocked with to assure trash checked for guards or 9 Exhausts and vents to assure they are areas shall be checked periodically exhausting into unoccupied c Approved dust masks shall be used as specified in Safety Rules and inspected monthly monthly 2- Personnel should be thoroughly trained in how to properly fit the masks or respirators to the face as per the manufacturer's recommendations Responsibility It is the responsibility of the area supervisor in whose area dust collection systems are located to see that they are inspected and recorded on IBM cards according to this procedure SUMMARY - Old Hickory has attempted to pool present knowledge of the asbestos dust problem with the information obtained from plant sampling to do the following 1 clarify the differences between level identification - MPPCF and fibers 2 determine realistic TLV 3 identify jobs and materials exceeding TLV 4 reduce exposure by specifying equipment modifications or additions changes in job procedures and use of suitable respirators where levels cannot be lowered sufficiently The recommendations contained in this report are based on analysis of the problems imposed on the only groups of people on the Old Hickory plant site routinely exposed to asbestos dust the pipe insulators Other job classes and other plant sites may have particular problems which go beyond old Hickory's considerations DUP 1012418 DU 053465 10 Asbestos dust hazards can obviously be greatly minimized by controlling exposure concentrations to safe levels Old Hickory's selection of a safe level is equivalent to 20 of the present recognized industry standard Further it is believed that the best way to obtain this level is to control it at the source thereby reducing the instances where respirators are needed DUP 1012419 DU 053466 11 \ ACKNOWLEDGMENTS The assistance of the following individuals is gratefully acknowledged - Oa C. D. Crook Analytical Analytical Research 2 Peer 7593 7593 Laboratory 8-144-7679 8-144-7679 Old Hickory Bureau of Mines U.S. Department of Interior Pittsburgh Pennsylvania Lynch Bureau of Occupational Safety & Health U.S. Department of H.E.W. Cincinnati Ohio Murray M.D. Medical Supervisor old Hickory Rose J. R. Smith Felix Stein Secretary of American Conference of Governmental Industrial Hygienisis Cincinnati Ohio Chemical Control Laboratory Old Hickory Department of Occupational University of Pittsburgh Pittsburgh Pennsylvania Health Tracey Du Pont de Nemours Werk Uentrop Hamm West Germany Deutschland GMBH DUP 1012420 DU 053467 APPENDIXES DUP 1012421 DU 053468 COPY CC R. B. Hayden D. D. Drummond TO R. J. BLAIR FROM J. A. SIGMAN - LYMAN COX Wilmington Delaware August 8 1968 CONTROL OF ASBESTOS DUST The recommended rules and procedures contained in letters Cockrill me to be to Drummond dated 3/29/68 generally satisfactory but and are Rhodes to Kennedy seem to not complete in certain respects The additions that I think should be considered are outlined below 1. A goal level should be stated The Threshold Limit Value recommended by the American Conference of Governmental Industrial Hygienists is 5 million particles per cu ft of air cles Construction has set a goal of 5 hundred thousand parti- per cu ft of air Both values are average concentrations for an hour working day I think we should use the same goal as Construction 2 A procedure for monitoring the level of exposure should be established insulators insulators insulators insulators wear wear sample is collected Construction does this by having one of their dust sampler for an hour day One such once once a month a month at at at cach construction construction construction construction construction construction site site site site site The filter through which the air sample has been drawn drawn is is sent to Dr. Morton Corn at the University of Pittsburgh for microscopic to Queener examination See dated 5/29/68 We attached could do copy of letter Keuper the same thing However I suggest that we learn how to do the microscopic work ourselves This is something the Old Hickory laboratory is trying to do A method for collecting and examining asbestos dust samples was published in the Journal of Occupational Medicine dated January 1968 by Lynch and Ayer The title of their paper is Measurement of Asbestos Exposure If this article doesn't provide enough information it might be advisable to to visit Dr. arrange for someone from the Old Hickory Corn for instructions His address is Laboratory Graduate School of Public Health Department of Occupational Health University of Pittsburgh Pittsburgh Pennsylvania 15213 DUP 1012422 DU 053469 COPY _ 3 The procedure discussed above in item 2 should be used to determine whether or not our control methods as outlined in Rhodes letter of May 22 are good enough to hold dust levels at values such that the hour value is not likely to be exceeded This at The values is something else that old Hickory is working obtained in this way will show whether there are specific operations or activities that cause enough dust to require additional control or the use of protective equipment air masks or respirators I would think we would devise control measures in preference to specifying protective equip- ment If we find that we can't do this we will have established a basis for supervisory judgment for saying what dust condi- tions are sufficiently severe or irritating to require protective equipment In my opinion if we find that we want to adopt a safety rule respirators it should requiring the wearing of dust masks or apply to any dust that is severe or irritating not just insulation dust soda ash activated carbon are handled on the plant dust This might be coal or other dusty materials that 4 The procedure should outlaw materials containing crocidolite type asbestos In this connection the Purchasing Department .says we haven't been buying any products containing crocidolite 5. The The procedure procedure should should should contain asbestos outlaw outlaw pressure pressure sprayi spran yingg spraying of spraying of materialsmaterialms aterials that that materials materials that 6 A record should be compiled to show dates on which improved control measures were instituted e.g. when specific saws were equipped with exhaust systems when protective equipment was provided when specific instructions on mixing asbestos cement were established etc. 7 Medical records that Dr. Murray has compiled on personnel who work as insulators should be continued The interest commendable which When Old Hickory is showing in they gain skill in taking the subject is dust samples and measuring concentrations accumulate meaningful data on the amount of dust produced by identifiable devise improved control methods operations or activities and they should be assigned the responsibility for taking the lead in applying findings to other Textile Fibers plants and if it seems appropriate suggesting additions to the present Engineering Standard S2T which is on Threshold Limit Values of Air Contaminants LC'rbl Att 10-17-69 a DUP 1012423 oo . DU053470 COPY CC Lyman Cox Wilmington Delaware August 16 1968 O. W. HESSfiMANAGER OLD HICKORY PLANT ASBESTOS EXPOSURE HAZARDS Ref Letter B. F. Kennedy to R. J. Blair of 5/27/68 The reference letter pointed out Old Hickory's concern on the adequacy of present safety standards for employees exposed to insulation dust Old Hickory suggested that a departmental standard be set up requiring respiratory protection for employees working with insulation I have reviewed this proposal with the Division Engineer's Office who in turn have ment Haskell Laboratory counseled and other with the Engineering Depart- locations We conclude the following 1 Basically there is little technical knowledge today on level of exposure that is tolerable Accordingly there is considerable debate on what standards should apply to dust exposure 2 There have been many recent changes in the direction of minimizing personnel exposure For example pre- formed insulation outlawing of crocidolite insulation dust exhaust systems etc. The effect of these improvements are not quantitatively known Accordingly before adopting a standard requiring respiratory protection across the board a significant administrative problem we should obtain some quantitative facts of where we stand today I would like for old Hickory to take the lead in making this analysis and in turn give guidance to the department DUP 1012424 DU 053471 2 ' - - Specifically Old Hickory should first assure itself that it is in conformity with all the latest operating and procedural standards and then under these conditions measure dust concentra- tion at the various identifiable operations including not only insulation dust but coal carbon and other dust sources This will require developing techniques for sampling and measuring dust concentration Some thoughts along this line are contained in the attached letter from Lyman Cox Then let's judge our actual position standard standard of dust concentration in various operations against a of 500,000 particles per cubic foot of air This is the recently adopted by Construction and is tenth of the official Governmental standards From these data identify the problem areas of dust concentration exceeding the standard These findings should be made known to the department and used as criteria for adopting respiratory protection at Old Hickory and other plant , locations with Also your medical section should continue its insulators so that a continuing medical history for correlation with procedural equipment changes follow is available Old Hickory's concern in this area is justifiable and I believe with the above approach we can more realistically establish protective equipment standards Please advise if you have any questions DACRONfiMANUFACTURING DIVISION bhs Attach 10-17-69 s J. BLAIR PRODUCTION MANAGER DUP 1012425 DU 053472 ee EB | ee: ees eee COPY CC J. S. G. J. E. C. F. H. B. B. H. D. C. R. K. W. C. G. L. R. J. Queener Employee Rel Nemours Stopps M.D. Employee Rel Haskell Jones Purchasing Louviers Mackie Lewis Boyce Lang Mason Engg It tt " Constr 14 IT 11 0 Louviers 15 1 11 Weaver " # 1 Dorsch 11 t 1 Ham " " 00 C. J. Lawrence Jr. Engg Constr Louviers W. H. Zane Engg Design Louviers J. R. Allen Engg ESD Site Safety Supervisor Louviers Constr Wilmington Delaware April 5 1968 FIELD PROJECT MANAGERS F. C. BAYLIS ASHTABULA W. S. BRIGGS BEAUMONT J. J. BELL BREVARD A. D. DAY CAPE FEAR C. S. ANDERSON CHAMBERS WORKS W. S. FREE CHATTANOOGA H. S. STANTON JR CIRCLEVILLE W. G. HARRIS COLUMBUS SHOPS M. W. HARTNETT JR EAST CHICAGO W. C. MANNFAR FLORENCE K. G. CAUGHMAN JR HOUSTON ~ R. H. DAVIS KINSTON R. G. STERNBERGER LOUISVILLE J. K. ADDISON MARTINSVILLE W. A. SAMANS MAY SAFETY - DUST CONTROL A. S. TRUMPORE MEMPHIS W. BLAKE MOBERLY H. F. REDMILE OLD HICKORY W. S. LEWIN PARLIN F. H. FOWLER AFPM PONTCHARTRAIN E. M. VASS SABINE RIVER H. J. FEINEN SAVANNAH RIVER Te _ E. K. DRAWDY SEAFORD R. A. MINIARD SPRUANCE S. V. HINSON VICTORIA R. L. SPITZ WASHINGTON WORKS S. KREWATCH WAYNESBORO G. E. BARLOW JR WILM AREA J. R. BALDER MGR WILM SHOPS 7 Industrial work producing airborne dust particle contamination is recognized as a primary contributor to employee health problems The ability of the medical profession in identifying the personal respiratory disease of asbestosis and the establishing of the cause to be due to extended exposure to asbestos dust have created a serious industrial concern Federal and State legislation is being enacted to place the burden of proof on the employer for continuous conformance with Governmental Industrial Hygienists established Threshold Limit Values for specific materials The employer's problem becomes acute when employment medical examinations are not required for the employees DUP 1012426 DU 053473 COPY With the mentioned responsibility in mind and to assure atmospheric conditions which will not contribute to the employees health problems when working with asbestos fiber containing materials the Construction Division is initiating the following permanent air quality control program to be effective June 1968 Air Monitoring Environmental air monitoring shall be conducted to provide quantitative data for site evaluation of dust control efficiency and document air quality analysis needed to demonstrate conformance with established Threshold Limit Values TLV 1. The Threshold Limit Value for total dust count shall be 500,000 particles per cubic foot of air 2 Personnel monitoring will be conducted in the insulation shops on site locations One employee will be requested to wear the air sampler one eight day each month 3 Trained site safety personnel shall be responsible for the control operation and adjustment of the air sampling instru- ment recording required technical data associated with the - air sample mailing of air sample to laboratory for analysis and compiling records of analysis reports . when soliciting participation in the air monitoring program craft supervision and Safety Engineer should anticipate who will be involved in work which will produce the greatest dust exposure for what day of that month 5 The personnel air sampling instrument used shall be a Universal Industrial Equipment Company Millipore filter Model 440B qualified for explosion hazard areas air sampler The filter used shall be a .8 micron pore size Millipore Cat No. MAWG 037 AO Type AA in plastic holder This equipment will be assigned to the sites where air monitoring is required by the Division Safety Office DUP 1012427 DU 053474 COPY 3 f \ 6 The filter in plastic holder upon completion of air sampling shall be mailed by the site Safety Engineer to Morton Corn Ph.D. Graduate School of Public Health University of Pittsburgh Pittsburgh Pennsylvania 15213 attention Felix Stein A phase microscopy analysis of submitted sample will be made and a Safety Office report submitted to the site and the indicating a fibers below 5 micron Division length b fibers above 5 micron length and c total number of particles Reports indicating total particle count to be approaching or above the TLV will require determining cause of condition and taking corrective action to reduce particle count After improvement been applied a second eight sample shall be conducted analyzed and documented Atmospheric Dust Control The application of the following conformance with the established dust emission control recommendations should demonstrate dust TLV and provide effective 1. Materials containing Crocidolite asbestos fiber shall not be purchased or accepted for use Materials containing Chrysotile - and Amosite asbestos fibers are acceptable for use 2. pressure spray application of materials with any per cent of asbestos fiber content shall be eliminated 3 All power tool and equipment operations shall be isolated from other shop facilities and fabricating operations 4 All power shop equipment shall when operated have installed exhaust ventilation of sufficient capacity to remove dust particles at point of origin Exhausted dust particles shall be collected by an effective collector system which will not allow vent of dust particles to the atmosphere 5 Present controlled shop cleanliness programs shall be expanded A vacuum cleaner should be used in lieu of broom sweeping to remove dust particles from shop equipment work tables ledges floors etc. 6 A controlled materials handling program should be adopted to eliminate the emission of dust for example when opening and removing materials from shipping cartons or in the handling and mixing of asbestos cements DUP 1012428 DU 053475 COPY Respiratory Protection Severe or isolated conditions may require that respiratory protective devices be used Consideration should be made for adequate protection of people in adjacent areas to the work location producing this condition A supplied air respirator or a filter respirator manufactured by Mine Safety Appliance Co. Pittsburgh Pennsylvania Model Dustfoe 77 with filter number BM 21 97 should be used Your usual cooperation is anticipated in administering these dust controls CONSTRUCTION DIVISION s E. DIVISION KEUPER SAFETY SUPERINTENDENT KEK 10-17-69 DUP 1012429 DU 053476