Document MJBzYMkXM8L34p9x2qaM4R5xj

FILE NAME: Caterpillar (CAT) DATE: 1971 Oct 19 DOC#: CAT020 DOCUMENT DESCRIPTION: Report - CAT Tractor Co. Submitted to State of Illinois Pollution Control Board at Regional Hearing on Asbestos and Spray Insulation SUBMISSION OF CATERPILLAR TRACTOR CO. to State of Illinois Pollution Control Board at Regional Hearing on Asbestos and Spray Insulation Waukegan, Illinois October 19, 1971 CAT-1007362 015 J PREFACE It is the sincere desire of Caterpillar Tractor Co. to cooperate with and assist the State of Illinois Pollution Control Board in the prep aration of the proposed Asbestos and Spray Insulation Regulations R71-16 in accordance with the Environmental Protection Act of the State of Illinois. The purpose of this booklet prepared by Caterpillar Tractor Co. is to supplement the statement and document the information presented by the Company at the Regional Hearing on Asbestos and Spray Insulation Reg ulations at Waukegan, Illinois on October 19, 1971 } Included in this booklet are: (1) Caterpillar's concerns regarding the possible prohibition of asbestos brake linings; and (2) Caterpillar's recommendations relative to the proposed Regulations which would ban asbestos brake linings by 1975. Also included in Appendix B is a copy of Caterpillar Tractor Co.'s oral testimony presented at the Waukegan Hearings, October 19, 1971. CAT-1007363 015 TABLE OF CONTENTS PAGE NO. I. INTRODUCTION.............................................. 1 A. Purpose of Booklet B. Caterpillar Product Line II. CATERPILLAR CONCERNS......................................... 2 A. Proposed Regulation R71-16, "Asbestos and Spray Insulation" B. Definition of a Vehicle C. Reasons for Caterpillar Concerns 1. Prohibition of Asbestos Brake Linings 2. Some Types of Disc Brakes are Not a Solution III. PROBLEM IDENTIFICATION..................................... 5 A. Types of Caterpillar Product Brakes B. Brake Wear Products C. Asbestos Usage - Caterpillar vs. U.S. Consumption IV. OTHER CONCERNS............................................... 17 A. An Illinois Standard Would Dictate Worldwide Caterpillar Requirement B. Effect of Proposed Regulations on Illinois Caterpillar Dealers V. SUMMARY AND RECOMMENDATIONS................................. 19 APPENDIX................................. .................. 21 A. Caterpillar Product Line Brochure B. Caterpillar Oral Testimony, October 19, 1971, Waukegan, Illinois iii CAT-1007364 J V > i | 5 LIST OF FIGURES FIGURE MO. PAGE NO. 1. EXAMPLES OF CATERPILLAR EARTHMOVING EQUIPMENT 5 2. TORQUE CURVES OF FRICTION MATERIAL 6 3. TRACK-TYPE LOADER WITH RAISED BUCKET 7 4. TRACK-TYPE TRACTOR ENCLOSED BRAKE COMPARTMENT 8 5. OFF-HIGHWAY TRUCK, ENCLOSED, OIL COOLED, MULTIDISC BRAKE 9 6. FRICTION PLATE AND MATING PLATE FROM BRAKE IN FIGURE NO.5 10 7. MOTOR GRADER SHOE BRAKE (DRUM REMOVED) 10 \ 8. WHEEL TYPE LOADER CALIPER DISC BRAKE 11 9. ASBESTOS FIBER FROM NEW BRAKE LINING 5000X 14 10. NEW BRAKE LINING SCRAPINGS AFTER HEATING 5000X 14 11. DEBRIS FROM DRY BRAKE COMPARTMENT 5000X 14 12. DEBRIS FROM DRY BRAKE COMPARTMENT 5000X 14 iv CAT-1007365 015 I. INTRODUCTION A. Purpose of Booklet The purpose of this booklet is to supplement and support the oral statement made by Caterpillar Tractor Co- at the Regional Hearing on Asbestos and Spray Insulation Regulations at Waukegan, Illinois on October 19, 1971. Recommendations and suggestions contained herein are intended to apply only to products of a type and kind built by Caterpillar Tractor Co. The information presented is brief; the intent is to provide the Company's posi tion relative to the proposed ban on the use of asbestos brake linings. B. Caterpillar Product Line Caterpillar currently produces 52 models of track or wheeled earthmoving equipment (in addition to 53 models of Towmotor material handling equipment), all of which have braking systems which utilize asbestos friction material. The following list ing gives the number of models in each specific product line (Appendix A pictorially illustrates the Caterpillar product line): 6 - models 6 - models 5 - models 7 - models 5 - models 13 - models 6 - models 2 - models 2 - models of track-type tractors of wheel-type tractors and of track-type loaders of wheel loaders of pipelayers of wheel tractor-scrapers of motor graders of off-highway trucks of off-highway tractors compactors 52 - Total Models 1 CAT-1007366 015 I) II. CATERPILLAR CONCERNS A. Proposed Regulation R71-16, "Asbestos and Spray Insulation11 The specific portion of the proposed Regulation that concerns Caterpillar Tractor Co. is Part VII - Asbestos Containing Prod ucts, Section 702, which states: "The use of asbestos in the brake lining of vehicles manufactured after January 1, 1975, and sold for use in Illinois is prohibited." B. Definition of a Vehicle The lack of a definition for the word "vehicle11 in the proposed ^ regulation is of concern to Caterpillar Tractor Co. The Illinois Vehicle Code (Section 1-217) defines a vehicle as "every device, in, upon or by which any person or property may be transported or drawn upon a highway...". Although this definition could provide some clarification to the proposed regulation <iE included), it is obviously quite general. Earthmoving equip ment does not normally operate on public highways and is not designed for such use, although certain equipment such as the 613 Elevating Scraper is small and light enough to be driven on the highway in its movement from one job site to another; motor graders may also be used to repair and maintain existing roads. Regulatory statutes typically have differentiated between motor vehicles and earthmoving equipment. It is, therefore, the Company's suggestion that this distinction should be recognized CAT-1007367 015 3 > and dealt with by including the following definition of vehicle in Section 103 of the proposed Regulations: Vehicle - Any self-propelled device designed primarily for transporting persons or property on a street or highway. A specific definition of this type would properly exclude from the proposed Regulation earthmoving and construction equipment -- not designed primarily for use on public highways. C. Reasons for Caterpillar Concern Unaware of the full intent of the proposed Regulation and un certain as to whether or not Caterpillar product is included ' in the proposed Regulation, the Company felt it mandatory to present its case assuming the intent was to include earthmov ing equipment. 1. Prohibition of Asbestos Brake Linings It is the Company's concern that all "use of asbestos in brake lining...is prohibited." Asbestos brake linings are used in all Caterpillar product because of their demonstrated safety and durability characteristics (which will be discussed in more detail later). At this tine, Caterpillar is unaware of a safe substitute for asbestos brake linings (our experience with sintered metal brake material has been unsatisfactory). The brakes on some of Caterpillar's equipment are totally enclosed. The brakes on many models are immersed and rotat ing in cooling oil. In these cases, asbestos wear products CAT-1007368 015 A it cannot get into the atmosphere except possibly when the brake compartment covers are removed for service. Other models have brakes with shields which are not air tight and thus brake lining wear products can escape to the atmosphere. The characteristics of these wear products are described in Section III of this booklet. - Some Caterpillar models use caliper disc brakes, which are not enclosed, and the brake pads, containing asbestos, can emit their wear products directly into the air. 2. Some Types of Disc Brakes Are Not a Solution In the explanation of Proposed Regulations (R71-16), the statement is made: "It is contemplated that the ban will necessitate design changes, probably to disc brakes..." As previously mentioned, Caterpillar Tractor Co. currently utilizes caliper disc brakes on some of its models; however, asbestos friction material pads are still utilized in this type of brake because of the safe, sure stop they provide. It must be pointed out that caliper disc brakes are not an alternative solution to banning the use of asbestos brake linings. In fact, with the open nature of caliper disc brakes, it is easy for brake-pad wear products to be emitted. CAT-1007369 015 > III. PROBLEM IDENTIFICATION A. Types of Caterpillar Product Brakes Asbestos-type friction material is used for brake lining through out the entire line of Caterpillar Tractor Co.'s earthmoving equipment. A few of the models are shown in Figure No. 1: A is a wheel-type tractor, B is a motor grader, C is a wheel-type FIGURE NO. 1 EXAMPLES OF CATERPILLAR EARTHMOVING EQUIPMENT loader, D is a wheel tractor-scraper, and E is an off-highway truck. Asbestos friction material is not used in Caterpillar's brakes frora happenstance but is chosen for its performance, re liability and safety. Sone of the products use dry friction surface brakes and some are bathed in cooling oil. For example, the off-highway truck (E) has totally enclosed oil cooled multi disc brakes while the wheel tractor-scraper (D) has shoe brakes. Each product (e.g. , truck, wheel tractor-scraper, etc.) requires a specific brake type and friction material depending on its primary application. 5 CAT-1007370 015 7 in noise and undue stress in the whole brake system. The abrupt change to a static level at the end of braking (as circled in Figure No. 2 on the right of curve B) causes instability and an erratic, unsafe brake operation. FIGURE NO. 3 TRACK-TYPE LOADER WITH RAISED BUCKET If a track-type loader (see Figure No. 3) stops abruptly, rather than smoothly, while backing up with a raised bucket full of rocks, some of the rocks leave the bucket and continue in the rearward direction and end up in the operator's lap. This safety hazard also applies to ether earthmoving machines which can spill a load due to an abrupt stop. CAT-1007372 015 8 FIGURE NO. 4 \ TRACK-TYPE TRACTOR ENCLOSED BRAKE COMPARTMENT I The enclosed brake compartment in Figure No. 4, shown with covers removed, has band brakes (noted by arrows), which are used either dry or bathed in oil. In either case, due to the enclosure, brake wear products cannot be emitted into the am bient air during normal operation. When servicing these compartments, they are exposed to the ambient air and the products found (Figures No. 11 and 12 and discussion) are powder rather than fibrous in nature and submicron in size. CAT-1007373 015 9 ) FIGURE NO. 5 OFF-HIGHWAY TRUCK ENCLOSED, OIL COOLED, HULTIDISC BRAKE Figure No. 5 is an example of multidisc brakes which are totally enclosed and bathed in cooling oil. The only time brake wear products from this type brake are exposed to the ambient air is during servicing. This brake was originally designed to use sintered metal friction material. Poor performance, re liability, and safety requirements necessitated a change to asbestos-type material. CAT-1007374 015 i 10 Figure No. 6 shows the asbestos containing friction plate used in the previously mentioned multidisc off-highway truck brake design. This design of disc brake system cannot emit wear prod ucts into the air during operation cue to its oil environment and the fact that it is contained in an enclosed compartment. FIGURE NO. 7 MOTOR GRADER SHOE BRAKE (DRUM REMOVED) CAT-1007375 015 11 Figure No. 7 shows a shoe brake located in the wheels of rubbertired eartr.mcving equipment. Motor grader shoe brakes of this type normally are shrouded to protect the operating mechanism. The shrouding may allow brake wear products to be emitted into the ambient air since it does not provide an airtight compartment. FIGURE NO. 8 WHEEL TYPE LOADER CALIPER DISC BRAKE Convention::! caliper disc brakes are also used on Some Caterpillar product ar.i are shown in Figure No. 8. The pads in the brake cal iper ccr.z'/.r. asbestos. With this type of brake system any brake wear products are emitted directly into the ambient air. CAT-1007376 015 12 The heavy-duty performance of Caterpillar machines and their braking requirements are considerably more stringent than auto motive applications and need to be explained. It is normal for track-type or wheel loaders to go forward and reverse as frequently as 180 times per hour, all day long, and often three shifts a day. This means as many as 360 brake applications per hour. Bulldozing operations also require severe usage of brakes since track-type tractors are steered by the brakes. Caterpillar 666 Wheel Tractor-Scrapers weigh 250,000 pounds when loaded to capacity. Typical applications will find these ma chines going downhill when fully loaded. The brakes on a 250,000 pound scraper, stopping from 45 miles per hour on the level, con vert enough energy into heat to melt 41 pounds of iron. (A typical passenger car stopping from this same speed would develop enough heat to melt 2/3 of a pound of iron.) Of course, downhill opera tion increases the energy dissipation further. Off-highway trucks weigh slightly less and must perform in similar situations. Pipelayer brakes must hold as much as 200,000 pounds of pipe sus pended over a trench, while men are working beneath the pipe. Track-type tractors often operate in conditions where very steep slopes must be negotiated (in forward and reverse). Since these machines are steered by the brakes, the safest possible linings must be used to prevent brake failure which could result in a machine attaining runaway speeds on these steep slopes. CAT-1007377 015  13 It is Caterpillar's candid opinion that the prohibition of as bestos from brake linings would place a severe penalty on the performance and safety of earthraoving equipment. B. Brake Wear Products In the December 1968, Air Pollution Control Association Journal, Jeremiah Lynch presented'the results of his study entitled "Brake Lining Decomposition Products." In an initial study, dust samples taken from automobile brake drums were examined. Electron micro graphs did not reveal the presence of any free fiber. Additional study, on a laboratory basis, was conducted. Decomposition prod\ ucts of various brake linings were sampled under simulated operating conditions. In all but a very few cases the linings tested showed less than 1% free absestos fiber in the decomposition product. This is a significant finding since the original linings averaged 50% asbestos by weight. In the isolated cases where significant free asbestos fiber was found, the test conditions were such that brake failure would have occurred if the linings had been sub jected to like conditions in a vehicle. Lynch states that in all but the most extreme driving conditions, only a very small fraction of the 302 -- 50% asbestos present in brake lining escapes into the ambient atmosphere as a free fiber. Wear apparently occurs not by abrasion but in minute areas of intense heat at points of contact between the drum and lining. At these temperatures, about 900F . , decomposition products do not generally contain free fiber, but are a different mineral resulting from the thermal breakdown of the asbestos. CAT-1007378 n-is 16 It should be pointed out that there are well over 100 different natural minerals having a degree of fibrous structure. Some in vestigators consider respirable fibers to be ubiquitous (everywhere at the same time) and feel that much more definitive information must be obtained on their identification, source, and biologic response. A good example of this is talcum power which is found in almost every home and is a measurable source of asbestos fiber. Tremolite, another form of asbestos, occurs naturally in most talc used in this country and is thus found in talcum powder. In dustrial talc may contain as much as 30% tremolite. Since more than 750,000 tons of talc are used in this country annually, it must be considered to be a prime source of respirable asbestos fibrils. (The finest single fiber shown in Figure No. 9 can be called a fibril.) C. Asbestos Usage - Caterpillar vs. U.S. Consumption Finally, it should be pointed out that of the more than 800,000 tons of asbestos used in this country each year, only about 3% of this goes into the manufacture of friction materials such as brake linings. Caterpillar's dry brake asbestos material usage amounts to 0.006% of the total asbestos usage in the U.S.A. and less than 0.2% of the total friction material usage of asbestos in the U.S.A. It is felt that the amount of free asbestos fiber that can potentially become airborne, as a result of breakdown of brake linings of earthmoving equipment, is quite low and u n likely to be significant from a health standpoint. CAT-1007381 015 IV. OTHER CONCERNS A. An Illinois Standard Would Dictate Worldwide Caterpillar Requirement The establishment of a standard which prohibits the use of a material in vehicles which are manufactured and sold for use in Illinois has the effect of setting national or even inter national standards. It is impossible to knc" the ultimate destination of Caterpillar machines as they are assembled and to provide for selective assembly or alternate brake sys tems for those to be sold in Illinois. In order to provide competitive leadership on a worldwide basis, Caterpillar has established the policy to use interchangeable parts on all models so that specifications can be followed for purchase and manufacture at any plant in the world If there were a material that would do the same job as asbestos in brakes, it is highly improbable that it could be a direct substitute. Other mechanical parts would have to be modified to adapt this new material. The results would be an "Illinois only" machine with parts only available locally, not worldwide. The customer could immediately react to this and buy a standard machine in a neighboring state and move it into Illinois as a used machine. Caterpillar Tractor Co. has long been a leading and vitally im portant company in Illinois. As the state's largest private employer with over 41,000 employees and 6 manufacturing facilities, it has become the largest dollar exporter of product in the United 17 CAT-1007382 015 18 States. Over 52% of the $2.1 biliion annual sales reached in 1970 were outside the United States. Illinois would not be the leading state in exports to other countries without Caterpillar. Imposition of a ban on the use of asbestos in brakes would impose a severe restriction upon Caterpillar Tractor Co. B. Effect of Proposed Regulations on Illinois Caterpillar Dealers The requirement for a specific design of earthmoving equipment for Illinois could result in a hardship for Caterpillar dealers and Illinois earthmoving contractors, and a subsequent loss of sales tax to the State. Special brake assemblies to meet the ' Illinois requirement would, of necessity, result in higher first cost of product. This higher first cost would result in higher bid prices for road building and earthmoving contracts. Thus, with a fixed State budget for road improvement, etc., less work would be done, and fewer machines would be sold. CAT-1007383 015  I 1. That asbestos brake linings (friction material) may be used in a brake system when the friction material operates in either a dry or oil-wetted environment in a totally enclosed brake com partment which prevents the emission of brake wear products into the ambient air. 2. That asbestos brake linings (friction material) may be used in a brake system, when the friction material operates in a nonenclosed brake compartment, until conclusive medical evidence proves that the emitted brake wear products contain harmful amounts of asbestos fibers. If all evidence indicates the need for asbestos brake controls and/or regulations, Caterpillar would further recommend that reasonable threshold limits of asbestos fiber be established by qualified per sonnel (based on scientific fact and foreseeable technological advances). Test procedures which measure the concentration of asbestos fibers must also be developed which are understandable. repeatable, and realistic. Place the burden on the manufacturer to design his product to meet rea sonable, attainable standards -- don't just prohibit the use of asbestos for brakes. As mentioned at the beginning of this booklet, Caterpillar Tractor Co. agrees in principle with the objectives of the Environmental Protection Act. The Company stands ready and willing to assist the Board in the establishment of asbestos regulations which serve the intent of the legislation. CAT-1007385 015 APPENDIX' B ORAL TESTIMONY by CATERPILLAR TRACTOR CO. to State of Illinois Pollution Control Board at Regional Hearing on Asbestos and Spray Insulation Waukegan, Illinois October 19, 1971 CAT-1007386 015  Mr. Chairman, members of the panel, my name is Fred Engelking. I joined Caterpillar in Peoria in 1937 after receiving a degree in Chemical En gineering from Purdue University. X have been working on friction materials for over 20 years. Presently, I direct the Research and Development pro grams for nonmetallic materials, including friction material, in the Research Department. I have been a member of the American Society for Testing Materials subcommittee on Friction Materials since 1957. Caterpillar is pleased to have the opportunity to appear before the Board today. We have six manufacturing facilities in the state, and are the largest private employer in the State of Illinois, with over 41,000 em ployees. We are vitally interested in the efforts of the Illinois Pollution Control Board to guard the health and environment. I am here today to present to you information that I hope will assist you in efforts to regulate the use of asbestos and spray insulation in the State of Illinois. Copies of our complete submission are in your hands, and it is our sincere hope that each of you will find time to read the entire booklet. My oral remarks are included in Appendix B. The Caterpillar product line includes primarily earthmoving equipment. All of this equipment utilizes asbestos brake linings and it is for this reason that we are concerned with Section 702 of Part VII of the pro posed Regulation. Appendix A of the booklet provides a listing of the Caterpillar product line which includes 52 models of earthmoving equipment and 53 models of material handling equipment. CAT-1007387 015 t i t - 2- The lack of a definition for the word "vehicle" in the proposed Regulation is also of concern. Typically, regulatory statutes have differentiated between motor vehicles and earthmoving equipment. There are suggestions for the definition of "vehicle" in the written testimony. There are reasons for our concern: Asbestos is used in all types of brakes in all Caterpillar machines because it has outstanding safety and durability characteristics. In spite of many years of research,, there are no known safe substitutes for asbestos brake linings for our type of equipment. I would like to acquaint you with a few I types of machines other than the familiar track-type tractor. SLIDE 1 Starting in the upper left hand corner and going clockwise, there is a I wheel tractor, motor grader, off-highway truck and wheel tractor-seraper. I I A wheel tractor loader is in the center. i I Dnlike most vehicles you may know about, we have 5 different types of brakes. They are dry shoe brakes, dry caliper disc brakes, dry band brakes, oil cooled band brakes, and oil cooled disc brakes. j SLIDE 2 J ! Conventional shoe brakes with dry linings are used in wheel tractor- scrapers, motor graders and most wheel loaders. These brakes are always shrouded to minimize the entry of debris from the outside. Brake lining wear products can be emitted into the environment from this type brake. Smaller sizes of this type are used on passenger cars. CAT-1007388 -3- SLIDE 3 The second type is called a caliper disc brake. The asbestos-containing pads are forced to grip the disc to produce the braking power. This is the most exposed type of brake and.obviously, wear products can easily enter the environment. Many U.S.-made passenger cars are now using this type brake on the front wheels only. We use caliper disc brakes on all wheels of some loaders. SLIDE 4 The next three types of brakes are totally enclosed and may be less familiar to you. Wear products cannot be emitted into the environment due to their containment. Track-type tractors and track-type loaders use band brakes. In this photo, the covers have been removed from the compartments so that the brake's are visible. Our larger machines use band brakes bathed in cooling oil such as is shown. The smaller machines use a dry-type band brakes without oil. SLIDE 5 The fifth type is the totally enclosed oil-cooled disc brake used in our off-highway trucks. These have many discs which are forced to rub against mating steel discs and provide braking power. Due to large rubbing surface area and the oil media, there is very little wear in this type brake. There are no emissions into the environment. CAT-1007389 015 -4- SLIDE 6 This is a typical friction disc with its mating disc as is used in oilcooled, multiple disc brakes shown in the previous slide. Break Wear products: It is my understanding that the technical paper by Mr. Jeremiah Lynch of the U.S. Public Health Service on "Brake Lining Decomposition Products" has been entered into the record in earlier testimony before this Board at Granite City, Illinois. Ke have done similar, but less extensive work, on brake decomposition SLIDE 7 products. This slide shows scrapings from an unused brake as photographed with an electron microscope at high magnification. So you will have a better feel for this high magnification, the thickness of human hair at this same magnification would cover a screen twice as largo as we have in this room. I have included a 5 micron scale on this and the three succeeding slides because Section 601 in the proposed Regulation states that "only fibers of 5 microns or greater in length...shall be counted" in the emissions from a factory into ambient air. We believe that if it is safe for a factory to emit fibers less than S microns in length, it should also be safe for a brake to emit fibers less than 5 microns in length into the ambient air. Additional research by qualified medical personnel may even show that asbestos fibers much larger than S microns are safe in the ambient air. Since these are fibers scraped from unused brake material, they are larger than 5 microns. CAT-1007390 015 -5- SLIDE 8 Some asbestos fibers from new friction material were heated in an oven to remove the water of crystallization inherent in asbestos. This destroys the fibrous nature, and mechanically rubbing the deteriorated fibers further reduces the fibers to powder. This is a simulation of the formation of brake wear products. You will note no fibers are longer than 5 microns. SLIDE 9 A sample of brake wear products was taken from a dry brake compartment. There are a few fibers showing and they are much shorter than .5 microns. Dust or clumps of dust occupy most of the picture. SLIDE 10 This last slide on brake wear products from a dry brake compartment also shows very few fibers and none of significant size. There are many dust particles. he believe that our limited study substantiates the findings of Mr. Lynch of the U.S. Public Health Service, that few fibers are emitted as wear products from brakes. Smoothness of brake operation is vital to safe operation of Caterpillar equipment. You may have experienced a malfunctioning passenger car brake SLIDE 11 which grabbed and threw you forward at the end of a stop. This pair of curves shows what is happening when you brake a vehicle. In curve A, asbestos material CAT-1007391 015 - 6- is stopping the vehicle. The brake torque or stopping power builds up at the beginning, stays smooth and constant, and finally increases slightly at the end of the stop. The sintered metal friction material produces rough braking in curve B. There is a lot of vibration and noise followed by a drastic increase in torque at the end. The sudden increase in stopping power causes material to spill out of machines. SLIDE 12 If this loader is backing up with a raised bucket full of dirt or rock, and the machine stops abruptly, due to grabbing brakes, the material will spill out of the bucket and end up in the operator's lap. Smooth braking action is absolutely necessary for safe operation of our machines. Safety: When a brake is designed for a Caterpillar machine, there are three vital factors: safety, durability, and smoothness of stopping. Tne last two factors enhance the safety factor. The brake must be able to stop the machine in a reasonable distance, time-after-time. Asbestos brake materials have proven performance and durability. I would like to summarize and make some recommendations. Caterpillar Tractor Co. questions whether the intent of the Asbestos and Spray Insulation Regula tions is actually accomplished by the proposed ban of asbestos brake linings. If research work and data on ambient concentration levels of asbestos fibers which are detrimental to society establish a need for asbestos brake control and/or regulation, Caterpillar recommends that Section 702, Part VII of R71-16 (Asbestos and Spray Insulation Regulations) be modified to allow the following exceptions: CAT-1007392 015 -7- 1. That asbestos brake linings (friction material) may be used in a brake system when the friction material operates in either a dry or oil-wetted environment in a totally enclosed brake compartment which prevents the emission of brake wear products into the ambient air. 2. That asbestos brake linings (friction material) may be used in a brake system, when the friction material operates in a nonenclosed brake compartment, until conclusive medical evidence proves that the emitted brake wear products contain harmful amounts of asbestos fibers. If all evidence indicates the need for asbestos brake controls and/or regulations, Caterpillar would.further recommend that reasonable threshold limits of asbestos fiber be established by qualified personnel (based on scientific fact and foreseeable technological advances). Test procedures which measure the concentration of asbestos fibers must also be developed which are understandable, repeatable, and realistic. Place the burden on the manufacturer to design his product to meet reasonable, attainable standards -- don't just prohibit the use of asbestos for brakes. As mentioned at the beginning of this booklet, Caterpillar Tractor Co. agrees in principle with the objectives of the Environmental Protection Act. The Company stands ready and willing to assist the Board in the establishment of asbestos regulations which serve the intent of the legislation. CAT-1007393 015