Perception of Risk

Johns-Manville's Corporate Marketing department made this animated film for the A/C Pipe Producers Association, to sell asbestos-cement water pipe. It explains risk as probability, and dose and response with a threshold. It says the asbestos in A/C pipe is "locked in the cement binder", and that cutting the pipe with the recommended work practices keeps fibre levels under the OSHA limits then in force and those proposed. Most of the film is about drinking water: it says the water, not the pipe, decides how much fibre is released, and cites water surveys and cancer statistics from Duluth, Switzerland, Tennessee and Connecticut. It closes with quotations from the International Agency for Research on Cancer, Dr. Irving Selikoff, the National Cancer Institute and the American Water Works Association Research Foundation.

What it says about asbestos and health

It names asbestosis, lung cancer in smokers and mesothelioma from "prolonged or heavy exposure to airborne asbestos", and says every case has involved occupational exposure. It says that with the recommended work practices "the risk of working with AC pipe is virtually non-existent", calls the risk from swallowed asbestos "solely presumptive", and says A/C pipe "is not and never will be a risk to the public".

About this copy

Our copy is a transfer of a print from Johns-Manville's own film archive (box 15-90018), shown in full, 22:05 long. Produced by the Johns-Manville Corporate Marketing, Advertising and Sales Promotion Department. Made for the A/C Pipe Producers Association.

Transcript

A machine transcript of the soundtrack, not yet checked against the film; names and technical words may be wrong.

The world has never been and never will be free from risk. It is inescapable. It is life itself. And since the dawn of time, man has accepted it as a normal part of his daily activity. The perception of risk varies from situation to situation, from individual to individual. What one person considers safe, another may perceive as downright foolish, illustrating that the perception of risk is subjective, emotional, and often has little basis in fact.

All risks have one thing in common. They can be measured. There is a name for this measurement. It's called probability. Something is judged safe if its probability of risk is acceptable. However, safe does not necessarily mean free from risk.

A seemingly safe six-minute canoe ride, for example, carries the same risk of death as a 500 mile per hour commuter flight from Washington DC to New York City traveling the same distance by automobile the risk increases fivefold very few things to which we are exposed are zero risks but like the automobile and electricity there are non harmful ways to use potentially harmful things it's simply a matter of probabilities few risks are as well publicized and fraught with anxiety as the risk of cancer. While the fear of cancer alters our perception of risk, it cannot, does not, alter the probability of risk. Cancer, an unrestrained growth of cells, is not a single disease but a collection of many diseases caused by agents called carcinogens. Asbestos is a carcinogen. It is not alone. It shares this distinction with a growing list of common and exotic substances.

As a matter of fact, nearly Nearly 300 organic or inorganic chemicals, many of them known or potential carcinogens, have been identified in drinking water. Fact, not speculation, which has prompted a much closer examination of all pipe materials in common use to determine if any are above suspicion, since all contain toxic materials. The critical question with any toxic material is, at what exposure level does it represent a hazard? Medical research determines this by a concept known as dose response. The principle is rather straightforward. For every dose, there is a proportionate biological response.

Alcohol is a familiar example. For every dose of martini you drink, you can anticipate a proportionate biological response. Let's add another wrinkle to this concept, and it's a common-sense wrinkle. There is a dose small enough which will result in no measurable response. This level is called a threshold. Threshold effects are common.

We have thresholds for hearing, pain, heat, and martinis. Everything known about the potential hazards of asbestos indicates that it observes the rules of dose response. Therefore, a practical threshold or safe level level of exposure to asbestos must exist. If it did not, it would be difficult to reconcile the prevalence of asbestos in the environment with the absence of related diseases in the general population. Asbestos-bearing rock is found throughout the world. Geologists tell us that 470 million years ago, hot subterranean water dissolved rock layers containing iron, magnesium, and silica, creating veins of liquid minerals.

As the earth cooled, these minerals crystallized into the fibrous ore we know today as asbestos. 2,000 years ago, pharaohs and kings used this unique product of nature. Today, you don't have to be royalty to use asbestos. Practically everyone does. Over 3,000 products use asbestos, usually in combination with other materials. With With physical properties unmatched by any other natural or manmade material, asbestos is irreplaceable for the micro reinforcement of high performance products like asbestos cement pipe. Comprising less than 20% of AC pipe, these incredibly strong fibers are not free, but encapsulated or locked in the cement binder.

Picture, if you will, reinforcing rods in concrete. The distinction between free and bound asbestos is extremely important. Why? It determines the probability of fiber release, which in turn directly relates to the probability of exposure. It explains why asbestos cement pipe is a non-harmful use of asbestos. The ability of of asbestos to subdivide into microscopically small fibers is the key to its biological availability.

In other words, its ability to become air or waterborne and thereby inhaled or ingested. The biological effects of asbestos are believed to be a function of fiber shape and size rather than chemical composition. Generally, the longer and thinner the fiber, the greater the potential health risk. While the relationship between asbestos exposure and probability of risk is not a simple one, we do know this. The biological response to asbestos depends on dose and route of entry into the body, that is whether it is inhaled or ingested. Prolonged or heavy exposure to airborne asbestos can lead to asbestosis, a disease which impairs breathing.

In the In the case of smokers, high risk of lung cancer. And finally, to a much lesser degree, mesothelioma, a rare cancer of the chest or abdominal cavity. To date, all identified occurrences of these diseases attributed to asbestos have involved exposures in or related to occupational settings. In contrast to inhalation, a cause and effect relationship between ingested asbestos and and gastrointestinal or GI cancer does not exist. Everything from mice to baboons has been watered, forced fed, or dined at will on asbestos, as much as 6% of their total food intake. Result, no cancers.

These then are the risks for exposure to asbestos. High for heavy or prolonged inhalation exposure, exposure, solely presumptive with no proven risk for ingestion. Regulatory agencies internationally have set safe levels of exposure to airborne asbestos based on the number of fibers longer than 5 micrometers. The levels established by the United States Occupational Safety and Health Administration are an eight- hour time-weighted average of two fibers per cubic centimeter of air, a peak or ceiling concentration of 10 fibers per cubic centimeter of air. A proposal to lower these levels to 0.5 and 5 fibers respectively is now under consideration. Let's compare the existing and proposed exposure standards to fiber levels measured when field cutting or machining AC pipe.

Independent industrial industrial hygiene studies have confirmed that when recommended work practices are followed, fiber levels are not only far below the present two-fiber standard, but also meet the proposed one-half fiber standard. This should come as no surprise. Remember, the asbestos fiber is locked in the cement binder. The infrequency and short duration of field operations further reduce even these exposures. when recommended work practices are followed, the risk of working with AC pipe is virtually non-existent. Some of you are probably thinking that's a real plus, but what about waterborne asbestos? That's the real concern about AC pipe.

Well, let's let the facts speak for themselves. The prevalence of asbestos in soil results in its presence in most waters of lake, river, and well origin, and in distribution systems whether fabricated of asbestos cement or other materials. Surveys by the United States Environmental Protection Agency show that although there are sites with asbestos levels below present limits of detection, natural and treated waters in Montana, Oregon, Pennsylvania, California, Connecticut, Massachusetts, and Georgia have levels in the range of millions of fibers per liter. Similar studies in Canada concluded there is asbestos in all surface waters of all habited areas of Ontario and perhaps there always has been some asbestos there. Asbestos found in ice core samples dating back hundreds of years confirms that natural weathering and erosion have in the past and will for generations to to come release asbestos to surface watersheds and underground aquifers around the world. Another potential source of waterborne asbestos can be asbestos-bearing soil deposited in the pipe during installation or repair.

This can occur whether the pipe is ductile iron, plastic, or asbestos cement. A thorough flushing of the distribution system easily eliminates any long-term effects of soil contamination to provide house connections water distribution mains are tapped approximately once every 140 feet the industry recommends when tapping AC pipe while under pressure that equipment with a positive purge be used this ejects 99% of the asbestos cement chips and downstream flushing takes care of the rest another alternative is the the use of heavy wall tapped couplings supplied directly from the factory now the critical question does AC pipe contribute asbestos to drinking water conveyed through it a no- nonsense answer is a simple yes and no it depends on the water not the pipe as long as AC cement binder remains intact the release if any of the locked-in fiber is infinitesimal. However, certain corrosive or aggressive waters will attack even corrosion resistant asbestos cement. The most common of these are low hardness or a soft water and low pH or acidic water. Imagine aggressive waters as being hungry waters, not only hungry for calcium and magnesium in cement, but hungry for iron, lead, copper, zinc, and and cadmium in metallic pipe, hungry for organic residuals in plastic pipe, polyaromatic hydrocarbons in coal tar linings, and on and on and on. Aggressive waters take a staggering economic toll from the waterworks industry every year.

But the heaviest toll of all may be the toll in human lives. In 1974, a highly significant relationship was confirmed between aggressive water and cardiovascular diseases such as heart attacks. Cities with the softest water had twice the death rate from coronary disease as cities where the water was hardest. Economics alone argues strongly for treating aggressive waters. The loss of life punctuates the urgency. Though the AC pipe industry is not the first to spotlight the need for stabilization, it has been a leader in in taking positive steps to include aggressive water guidelines in national product specifications.

These guidelines do not recommend the use of asbestos cement pipe with highly aggressive waters. Measurements taken in the field confirm EPA laboratory results that for moderately and non-aggressive waters, AC pipe does not contribute significant, or in many cases, even measurable amounts of asbestos to drinking water conveyed through it. Northeast Illinois, an analysis of 15 public water systems containing A.C. pipe of various ages, lengths, and diameters. Conclusion, no significant release of asbestos from A.C. pipe was observed. California, an analysis of water at the end of long pipe runs in a distribution system with over 1,000 miles of A.C. pipe. Conclusion, all tests for asbestos, negative.

New Mexico, an analysis of asbestos fiber concentrations in water systems containing 548 miles of AC pipe. Conclusion, no evidence of asbestos pickup from AC pipe. Texas, Ohio, and Connecticut, EPA monitorings of AC pipe systems. Conclusion, fiber levels either not statistically significant or below detectable limits. Common sense tells us that real-world risk must relate to real-world exposure. For that reason, these results are important.

They measure actual exposures to waterborne asbestos in AC pipe systems. Clearly, the amount of asbestos, if any, contributed to drinking water supplied through AC pipe was infinitesimal, certainly far less than than was found in many natural source waters. Now what about water systems which have measurable quantities of asbestos fiber? What's the risk of contracting cancer? There is no evidence that anyone in the general public has ever contracted any disease from naturally occurring asbestos or the minute amounts of fiber released from AC pipe. This is not a judgment of safety.

It is a statement of fact. Whether it's the extremely small size of waterborne asbestos or the sub-threshold dose, one fact is irrefutable. If there is a cause-and-effect relationship between GI cancers, ingested asbestos, or the use of AC pipe, it does not show in state, national, or world cancer statistics. statistics. Duluth, Minnesota, millions of asbestos- like fibers in its drinking water and Houston, Texas, with none. A comparison of tissues from deceased residents from both cities failed to disclose any asbestos fibers of waterborne origin. Duluth again, this time a comparison with Minneapolis, St.

Paul, which has no asbestos in its water. No statistical statistical difference in the incidence of gastrointestinal cancer. Switzerland, the highest per capita use of AC pipe in Western Europe. From 1951, more than 20 years after AC pipe was introduced, to 1973, the death rate from GI cancer dropped a significant 29%. The United States, during 40 years of rapidly increasing AC pipe usage, gastrointestinal cancer rates for the period 1954 to 1974 declined 33% Tennessee Knoxville AC pipe in use since 1938 and Nashville no AC pipe a 20-year comparison shows that Nashville with metallic pipe at a 29% higher death rate from GI cancer than Knoxville with asbestos cement pipe Connecticut. Results from an extensive Environmental Protection Agency study show no correlation between the incidence of GI cancer and the use of asbestos cement water pipe.

This inability to relate a real-world response with a real-world dose again says that like the amount of asbestos contributed to drinking water by AC pipe, the risk from ingesting that asbestos must be infinitely small. An exact number? Well, we did say all risks could be measured. Let's create a hypothetical human feeding experiment based on magnified doses used in animal feeding studies which failed to establish a cancer risk from ingested asbestos. Based on a diet containing 0.27% asbestos, this amounts to about five pounds of asbestos, roughly the amount of butter you eat in a year. Using the highest fiber levels found in drinking water, you would have to drink 3.8 million quarts of water per day to consume five pounds of asbestos in a year, or in excess of 50,000 quarts per day for a lifetime.

This is preposterous, but it does provide a roundabout way to quantify and place in perspective the probability of risk from a real-world dose of ingested asbestos from AC pipe. A dose which is not uncommonly a billion times less than asbestos levels proven to be non-carcinogenic in animal feeding studies. One in a billion. That figure probably doesn't register with most people. In terms of quality, it's one bad apple in two million barrels. In terms of volume, it's a very, very, very dry martini.

One drop of vermouth in 15,750 gallons of gin. In terms of risk, it's a thousand times safer than smoking one and a half cigarettes or drinking a half bottle of your favorite wine. This is a statement of fact and certainly a margin of safety. In spite of perceptions and publicity to the contrary these incredibly low probabilities of risk tell us that AC pipe is not and never will be a risk to the public a judgment confirmed again and again by some of the most respected health authorities in the world international agency for research on cancer the question is there evidence of an increased risk of cancer resulting from asbestos fibers present in water beverages food or in the fluids used for the administration of drugs the answer such evidence as there is does not indicate any risk dr. Irving J Selikoff director of the environmental sciences laboratory Mount Sinai School of Medicine there is no evidence at all at this time that the presumably very low level exposure by ingestion which might occur by intake of water supplied through asbestos cement pipe has resulted in a recognized health hazard. National Cancer Institute.

NCI scientists have found no unusual cancer mortality patterns so far among persons residing where drinking water is contaminated by asbestos. Select Study Committee of the American Water Works Association Research Foundation. No firm evidence shows that the proper use of of asbestos cement pipe poses a hazard to health by reason of ingestion of asbestos fibers. The probability of risk to health from the use of such systems is small, approaching zero. False accusations and guilt by association have created a perception of risk about AC pipe. Scientific measurements and common sense show this distorted perception has no basis in fact. designed for value engineered for performance AC pipe is the optimum balance between high performance long life and cost-effectiveness quality control second to none assures high pressure reliability with sensible factors of safety consistently inexpensively and that's a a fact.

The AC pipe industry has a commitment, a commitment to quality water. This commitment encompasses much more than simple assurance of water quality at the consumer's tap. Regardless of how bountiful or clean water reserves might be, whimsical as nature can be, and short-sighted as man has been, quality water demands conservation in use, diligence in treatment, and economical reliability in distribution. Providing distribution pipe of integrity at a cost the user can and will support is the goal of the AC pipe industry.