of the material in the pathology departments of Scottish hospitals and medical schools from the years 1950 through 1967.

An additional disconcerting feature of the Scottish data was the rapid rate of increase. In the early 1950's perhaps one case a year was seen. From 1964 through 1967, 51 cases were seen. This time period corresponds approximately to 30 years after the increased shipbuilding activities that took place prior to World War II. So the elapsed period between onset of exposure and onset of disease is evident here. Unfortunately, this long lapsed period gives rise to a problem. We have no knowledge of the exposure that took place that gave rise to this disease experience 30 or 40 years ago. We only have knowledge of the fact that such exposure did lead to disease. The dose response relationship is unknown at this time. Obviously, additional research and continued surveillance are extremely necessary in this area.

With this background of disease, let us turn to some present day uses of asbestos, uses that would fall directly within the province of the legislation here under consideration.

Over 3,000 uses of asbestos have been documented and the list grows yearly. The total U.S. consumption has risen from 146,000 tons in 1920 to 730,000 tons in 1965. Fortunately, the largest growth in this case is in the use of asbestos that is unlikely to contribute to air pollution or to serious consumer exposure. Here the asbestos is locked into such variables as vinyl floor tiles, siding, and roof shingles, wallboard, and asbestos cement products.

Uses of asbestos in firable form with greater potential for environmental pollution include the application to and removal of insulation from pipes and boilers, the mixing and application of asbestos-containing dry cements, erosion from brake linings, and, in recent years, the fireproofing of high-rise buildings by a fibrous spray mixture containing from 12 to 30 percent asbestos. It is this latter use, particularly, that has given rise to extensive dissemination of asbestos into the business and residential community surrounding a construction site. For the past 10 years, during which spray fireproofing came to be extensively used, it was not uncommon to see extensive snowfalls of asbestos-containing material over widespread areas of New York and other metropolitan centers. In some cases, the fireproofing was even done with no attempt to enclose the spray area by tarpaulins or other means.

To verify that such fireproofing operations were indeed a significant source of respirable asbestos fiber, air sampling was conducted in lower Manhattan about construction sites where extensive spraying of asbestos-containing fireproofing was taking place. This work was done by our laboratory in conjunction with the Department of Air Resources of New York City. The results demonstrated that spray fireproofing can indeed contribute significantly to asbestos air pollution.

Up to one-fourth mile away, levels exceeding 0.1 micrograms per cubic meter were observed, which exceeds by 100 times background levels found in urban areas distant from construction sites. While 0.1 micrograms may appear to be a small amount, it could represent more than 10 million minute fibers of asbestos. Moreover, the large clumps of asbestos-containing material covering the sidewalk serve as a continuing source to be dispersed by passersby.

While I mentioned there was no known dose-response relationship between these levels and possible disease, if one looks at photographs which I will submit to you of this process taken 1 year ago in Manhattan where spraying was done with no attempt to control it or even when control measures were taken, it is difficult to imagine that factories even 40 years ago had more extensive emissions.

The method of fire protection for high rise buildings presents an additional, continuing risk to the occupants of those buildings. Often, the space between the false room ceiling and the underside of the floor above, which has been sprayed with asbestos, serves as a return plenum for the air supply system. After filtration, inadequate to remove most asbestos fibers that may have eroded into the airstream, this return air is recirculated throughout the building. The magnitude of this problem has yet to be defined. To date, in New York City, we have not been allowed to analyze the air in buildings that has been in direct contact with asbestos-containing insulation. Obviously, adequate testing of the effects of this procedure should be required.

Finally, this spray procedure leaves a legacy of potential risk to future generations. The lifetime of modern office buildings is short and the procedures for the safe future demolition of buildings that could contain more than 100 tons of asbestos as fireproofing have yet to be developed. Perhaps these procedures will be found in time and perhaps they will be followed. The bill under consideration here offers an appropriate instrument to require their development and

use.

Unfortunately, safe procedures developed for the spray application of asbestos-containing materials have not been followed voluntarily by contractors. Because of this failure and because alternative procedures or materials are available, action banning this use of asbestos has been taken by four cities: Boston, Chicago, New York, and Philadelphia. However, in the absence of national legislation, residents of other urban centers are still subject to a serious risk from this practice which last year utilized approximately 10,000 tons of asbestos.

I would like to list some additional uses of asbestos that exist that give rise of concern to consumers.

One is the suggestion that children mix asbestos with cement or paste to make jewelry, puppets, masks or other play items. This suggestion has appeared in several books, in Girl Scout Brownie Handbooks, and in State Art Education Association manuals. One asbestos producer, Johns-Manville, has gone to considerable effort to prevent the use of asbestos in this manner. Unfortunately, such efforts are not industrywide, and the difficulty of preventing it is extremely high. Recently, we learned of the existence of a woman's coat made with fiber material containing 8 percent asbestos. With the help of Mr. Henoch Mendelsund, president of the Cloak Joint Board of the International Ladies Garment Workers Union, the origin of the material was traced. An importer had the fabric made in Italy and attempted to import it into the United States as an "asbestos fabric." If allowed as an "asbestos fabric" the duty would have been 6 percent rather than the nearly 100 percent applicable to standard woolen textiles. More than 100,000 coats-and that was from one manufacturer-were made

of this fabric and are now worn by women throughout the United States. All had the fabric content appropriated listed; 72 percent reprocessed wool, 20 percent nylon, and 8 percent asbestos.

To assess the risk to users, we measured air concentrations of asbestos near a coat lightly brushed for 2 minutes. Levels of asbestos 10,000 times background were found. Ironically, there is, as yet, no mechanism to prevent future imporatation of similar material for use in clothing. The only defense consumers have at this time is the refusa' of the Ladies Garment Union members to work with such cloth.

Unfortunately, they do not control the entire industry, and some of this cloth now exists in nonunion shops.

The description of inappropriate or questionable uses of asbestos can continue. Let me just touch on a few. In the 1950's, perhaps even today, handfuls of asbestos were added to bulk containers of wine in case small leaks developed-recall that the incidence of gastro-intestinal cancer in asbestos workers is three times normal. Asbestos is now one of the "stop leaks" in your antifreeze. Gas masks and cigarette filters at one time contained asbestos-the synergism between cigarette smoking and asbestos made this latter practice particularly objectionable.

The spraying of asbestos from airplanes had been contemplated in fighting forest fires. The dusting of asebstos mine tailings over farmland depleted in magnesium was once considered. Fortunately, when the possible risks were raised with the asbestos producer who proposed them, these two practices were never implemented.

Here was a case of an enlightened management taking action on a procedure that could provide a risk to many people, but are all producers or manufacturers so enlightened or so ready to abandon a profitable sale?

I might conclude this abbreviated list by mentioning that asbestos filters are used in the purification of foods and of drugs. While this is outside the scope of this legislation, it is worth noting that extensive erosion of asbestos fibers in these circumstances can occur. We have found up to microgram amounts of asbestos in single-dose samples of many widely used injectable drugs. Not only are people breathing asbestos, they are mainlining it.

I hope this information on the effects and uses of asbestos has proven useful to you. It is a particularly apt substance to consider in assessing the need for consumer protection legislation. The full spectrum of problems that might be encountered in the use of hazardous materials is presented by asbestos. Knowledge of the full health effects is limited. The evidence of deleterious effects following exposure may be delayed many years with the consequent buildup of a reservoir of potential disease should a use be found later to be harmful. Exposures in combination with other hazardous materials may provide greatly increased risks. Finally, widespread use, in many diverse circumstances, makes surveillance difficult, if not impossible, under existing regulations.

Thus, the legislation here considered can be especially useful. The development of test procedures to evaluate health effects, the certification for use only after the establishment of safety, and the limitation on inappropriate uses of hazardous materials will go far in protecting the consumer and the environment.

Senator SPONG. Thank you very much, Dr. Nicholson. You have presented a very thorough documentation of the hazards associated with asbestos exposure.

Do we have enough data to suggest a level of exposure at which no hazard would exist? How much can we tolerate?

Dr. NICHOLSON. We have no knowledge at this time of a threshold limit, a threshold value that could assure that there would be no possible disease in any population or people. We have just the beginnings of information indicating that there are levels of asbestos measurable in virtually all cities of the United States. So, we are living with a background of asbestos, some of which would come from occupational uses, some of which would come from natural resources. One natural source is the Appalachian Mountains, in part made up of serpentine rock, which contains within it chrysotile, an asbestos mineral. We only know that we have so far identified no observable disease at these background levels, but we don't know at what level greater amounts of asbestos might produce disease. Our knowledge at low levels is very poor.

Senator SPONG. In your statement, you mention the danger that might occur in the future from destroying buildings which are not now being built using asbestos as a fire retardant. I am curious as to whether asbestos is now being released from buildings which were built 50 years ago and which also contain asbestos.

Dr. NICHOLSON. The buildings that were built 50 years ago would have their asbestos predominantly in the insulation material, in the pipes and the boilers. Recently I saw one bizarre circumstnce at the time some of these pipes were being removed. The pipe insulation material was taken out by men who wore no respiratory protection in very small enclosed tunnels. It was loaded in a cart and wheeled through hallways with much of the material falling off. It was then loaded into an open truck and driven through the streets of New York.

The material after having had high temperatures applied to it for many years is extremely friable. So a considerable amount of asbestos was dispersed within the building and then into the environment of many people in New York City.

Senator SPONG. You have stated we are leaving a legacy to future generations by our use of asbestos in buildings and that when these buildings are torn down 50 or 75 years from now the asbestos once again will cause problems. Under the legislation we have before us, EPA would be authorized to set use restrictions on substances such as asbestos. I am curious as to how a use restriction might be fashioned to solve a problem like asbestos contamination from the demolition of old buildings. Do you have any thoughts on how this might be done?

Dr. NICHOLSON. This is a very difficult question to answer at this time. There has been absolutely no research done on the methods by which current buildings to which sprayed fireproofing material containing asbestos has been applied can be safely demolished. It is something that construction people simply say, "Wait until the time comes and we will find out what to do." We don't really know.

One could give some of the top-of-the-head answers. We are clearly going to need enclosures that will prevent the dissemination of asbestos. The form of these enclosures has as yet to be developed. We need a lot of work in that area.

Senator SPONG. In your statement, you cite the risk associated with asbestos-coated air ducts. Would you give us an estimate of how many structures contain this type of duct system so we might get an indication of the magnitude of the problem?

Dr. NICHOLSON. In New York at this time, there are perhaps 40 buildings being constructed. I would guess, and it is only a guess since I did not survey those buildings, that at least half of them have an air-conditioning system constructed in this way. It is by far the most economical procedure to use. It is in a very large number of buildings. Senator SPONG. It has come to my attention that asbestos is used in the brake lining of automobiles. If this is correct, the possibility exists that asbestos may be released as the brake linings wear out.

Could you tell us if brake linings are indeed a source of asbestos and if there is any indication that a hazard may exist?

Dr. NICHOLSON. They are a probable source of asbestos. We have had a brief look at this question, but a considerable amount of work has to be done. In one of the very brief measurements made, we found levels of asbestos near where extensive braking took place that were perhaps two or three times higher than measured a few blocks distant. This could be due to variability in the sampling technique. It could be due to a real emission from the brakes. The levels indicate that it is not nearly the problem of sprayed asbestos where rise to extremely high levels. It is a problem, though, that should have much greater study done.

It is clear that some asbestos does get off the brakes when one does laboratory studies of the brakes themselves. How much gets into the environment through extensive use is still pretty much an unknown question.

Senator SPONG. It has been suggested that the definition of a chemical substance under the legislation might not include a substance like asbestos because asbestos is not an uncombined chemical radical or element and does not have one particular molecular identity. Would you agree in this assessment?

Dr. NICHOLSON. It is true that asbestos is not a particular chemical substance. It is a generic term applied to a group of chemical substances. There are five or six mineral species which are definite chemical compounds to which the term asbestos is applied and each one of these separately would directly fall within the definition of chemical substance.

Senator SPONG. Would you say that asbestos comes within the definition of a chemical substance that I referred to?

Dr. NICHOLSON. I would say that the minerals to which the term asbestos is applied fall within the terms of this legislation, in particular chrysotile, crocidolite, amosite, tremolite, anthophyllite, all asbestos minerals which directly fall within the terms of this legislation. Since all forms of asbestos separately conform to the definition of a chemical substance, asbestos clearly falls within the scope of the legislation.

You could, if necessary, use the language of a specific mineral rather than the term asbestos, but the objection raised is a trivial semantic one with no real substance.

Senator SPONG. Your testimony says that asbestos presents a hazard to human health with its current usage. Are there any alternatives to these uses that present less hazard?