The Ramazzini Institute
for Occupational and Environmental Health Research   

Inside

Who Are We?

Introduction
Carbon black is sometimes confused with soot, but it is a very different material. It is a powdered form of elemental carbon manufactured by the controlled vapor–phase pyrolysis of hydrocarbons. There are many different types of carbon blacks. There are four principal methods of manufacture : furnace, channel, lampblack and thermal black processes, as well as special ones, e.g., the acetylene process. Carbon black is an essential ingredient of thousands of industrial products. However, over 90% of carbon black produced is used as a reinforcing filler in elastomers, mainly in the manufacture of tires. Some other important applications are pigment in inks, paints, paper and plastics, conductive fillers, radio frequency insulators, dry cell batteries, magnetic tapes, UV stabilizers and antioxidants in plastics and photocopy toners. The workers are potentially exposed to carbon black during its manufacture and while using this product.

The History of Carbon Black
Ancient advanced civilizations, like those of the Chinese, Indians, Egyptians, Greeks and Romans, required carbon blacks for watercolors, inks, so they were able to decorate the walls of their buildings. Essentially nothing has changed in the production process for centuries, from ancient times to the 19^th century. Lampblack in the new era of production was first produced commercially in the USA in 1840, where it was separated from the gases and made into pellets. Another type of carbon black – the channel black experienced a rapid upswing in demand, especially after the discovery in 1904 of usefulness in reinforcing filler for rubber. From 1910 carbon black was used as a reinforcing agent in tire production.

Manufacture of Carbon Black
Carbon black is manufactured by a number of different methods. The highly aromatic oil feedstock is steam atomized into the reactor, which is at a temperature of 1200 –1850 °C. The feedstock is either pyrolised under reduction conditions, or is cracked wherein the carbon atoms are dissociated from the other elements present in the oil. The mayor by – products are gases, called „production gas” and after cooling are separated from carbon black.. As a result of legislative restrictions on direct emission and of the high energy content to this gas, it is used in other processes such as power generation and community heating. The major problem for employees (during production processes and usage) is carbon black concentration in the air and the possibility of a dust explosion, so all methods of controlling hazardous conditions must be done. There were many articles about these problems.

Occupational Exposure
Industrial hygiene studies of production processes, the major carbon black use industry, tire manufactury and so on found mean dust levels from < 0,5 mg/m³ to > 100 mg/m³. Regulations limiting occupational exposure to carbon black at a TWA of 3,5 or 4,0 mg/m³ are found in many countries, although a few allow higher exposure, e.g. Germany – 6,0 and Switzerland – 8,0 mg/m³. Organic solvent extracts of carbon black contain mainly four or more Polynuclear Aromatic Hydrocarbons [PAH], among which are known or suspected animal mutagens and carcinogens. However, PAH interact strongly with cabon surface, and are not readily bioavailable when adsorbed on carbon black.

Toxicology and Health Aspects
The production and use of carbon black normally results in the workers in the industry coming into contact with the bulk materials or dusts that may arise when carbon black is handled, resulting in a certain amount of risk. A number of studies have been published in which various species of animals have been dosed with carbon black. All studies performed with experimental animals have reached contrasting conclusions regarding the hazard of exposure to carbon black.[3]  Most of the reports, describing the effects of carbon black on humans have dealt with pulmonary effects, while only a few have studied its effects on oral mucosa, skin, the heart, the digestive system, or as a cancer hazard. The overall results of all epidemiological studies have been the subject of controversial scientific discussion for decades. In about half of all reports, there is some speculation about a carcinogenic risk of workers employed in the production processes and use of this substance. There are two points of view on this subject: some believe carbon black is a potential carcinogen while others think it is not. For proper assessment of the toxicity of carbon black and its potential hazard to the working population, further animal and human study is needed.[4]

Ecology
Most of the energy generated globally is based on the combustion of coal and fuel oil. The combustion of carbon containing materials is one of the main contributors to world – wide pollution of the atmosphere. Besides carbon dioxide, the pollutants NO₂ and SO₂ are the major concern. Since legislation in different countries has become more stringent, these pollutants provide an environmental and an economic challenge also to the carbon black producer. Carbon dioxide in particular is held responsible for global changes of the climate by increasing ambient temperatures, through a phenomenon known as the ‘green house’ effect. Carbon black and energy are closely linked in terms of both raw materials and final products. The feedstock used for the production of carbon black consists of aromatic oils that also can be used for generating heat. During the production process only about 50% of the hydrocarbons used as feedstock and fuel are converted into an off-gas contributing to the carbon dioxide level. The rest of the carbon in the form of carbon black may be considered as a product with a hidden energy.
     Carbon black itself is a potential carbon dioxide producer and CO₂ may be its final destiny. However before the end of its life it contributes to the lifestyle of mankind. It is used in the rubber industry and as pigment and in some other applications. At the end of the lifetime of all of these products, it is very probably that they will be burnt producing energy. Nevertheless, they would not then contribute to the green house effect, because they would replace fuel oil or coal, which would otherwise be needed for energy production. Carbon black itself can be a source of energy.
     The development of risk assessment procedures for airborne particles and gases has evolved over the years. During the last several years the use of data on the mechanisms by which particles and gases cause disease has been suggested to reduce the uncertainty in estimates of human risks from exposures to them. Carbon black may often be produced from recycled materials, for example, from oils derived from scrap tires. It is possible that there is no ecological problem at all, since in these processes recycled products can be used. An ecological perspective in environmental health would mean that solutions to environmental health problems would be sought by adopting a much broader and longer term perspective. To find effective solutions we need to understand much more about the natural world and work in partnership in nature. These must be understood by all carbon black producers and users.

The Carbon Black Industry and It’s Future
Carbon black differs from other carbon – based materials in many respects, an important one beeing that of bulk density. This property has prompted carbon black production facilities to be located as close as possible to consumers, since when compared with carbon black feedstock, the transportation costs are considerably higher. As a consequence carbon black plants are concentrated in those parts of world where major portions of industry requiring this material are located. Carbon black plants are distributed all over the world: in North America, Western Europe, Eastern Europe, Asia , South America, Africa , and Australia, for a total of 146.
     The future of the carbon black industry lies in the development of environmental ecology policies by both producers and users. Carbon black is still a necessary product. There were, there are and there will be some differences in production processes, ecology, exposure and health conditions of carbon black workers throughout the world. Carbon black is a pathogenic factor of some diseases and ecology. There is a need for continuous monitoring of workers health condition, as well as for improving the working conditions where they are employed.

Selected References on Carbon Black

Szozda R.: The respiratory health of carbon black workers – differences between Polish, West European and American Scientific Reports. J UOEH 1994, 16 (1), 91 – 95.

Szozda R.: The history of carbon black production and preventive health programs in carbon black industry in Poland. In.: A.Grieco, S.Iavicoli and G.Berlinguer (ed), Elsevier Science B.V. 1999; 233 - 239.  

Szozda R.: Characteristic features of workers exposure at the „CARBOCHEM” Carbon Black Factory in Gliwice (in Polish) Medycyna Pracy 1994, 5, 399 – 404.  

Szozda R.: Condition of the respiratory system in workers involved in carbon black production. (in Polish) Medycyna Pracy, 1994, 1, 57 – 61.  

Szozda R.: The circulatory system in workers involved in carbon black production. (in Polish). Medycyna Pracy, 1994, 5, 405 – 410.  

Szozda R.: Pneumoconiosis in carbon black workers. JUOEH 1996, 18 (3), 223 – 228. 

Szozda R.: Effects of carbon black in health of workers involved in the production process (1999). Comparison of our own results with those obtained by foreign authors. (in Polish) Medycyna Pracy 2000, 2, 139 – 144.  

Criteria for a recommended standard: Occupational exposure to carbon black. USDHEW, PHS, CDC, National Institute for Occupational Safety and Health, Washington, DC 1978.

Monographs on the evaluation of the carcinogenic risk of chemicals to humans: Polynuclear Aromatic Hydrocarbons. Part 2. Carbon blacks, mineral oils (lubricant base oils and derived products) WHO, International Agency for Research on Cancer, Lyon 1984.

Monographs on the evaluation of the carcinogenic risks of chemicals to humans:  Printing processes and printing inks, carbon black and some nitro compounds. WHO, International Agency for Research on Cancer, Lyon 1996.

Meet a GEE!  Reader!

Ryszard Szozda was born in 1955 in the town of Gliwice, where he graduated from the Silesian Medical Academy in 1980, and later studied  Occupational Medicine, with additional degrees Social Medicine and Health Protection. He has worked in the Town Hospital in Gliwice and as head of Occupational Health Care Units, but also in the Military Hospital as a consultant. His staff includes a psychologist, laryngologist, neurologist and ophthalmologist. They serve some six to seven thousand patients: carbon black workers, other chemical industries workers, construction industry and teachers, doing prophylactic examinations and cooperating with factory management in the organization of health protection. Author of 130 papers, he is active in the Polish Societies for Occupational Physicians and Occupational Hygienists, and the International Commission of Occupational Health.

Human Ecology
Workers Memorial Day
Raises An Important Question
     Each year since 1989, unions in the United States, and now through much of the industrialized world, dedicate April 28 as Workers Memorial Day. April 28, 1971 is the date the Occupational Safety and Health Act of 1970 went into effect. The theme is constant, a refrain from Mother Jones, a revered union organizer: Mourn for the Dead, Fight for the Living! More than three decades have passed since the passage of the OSHAct, and similar legislation has been enacted in many other countries. Why is April 28^th still an important day?
     Part of the answer lies in every issue of the dozens of medical and scientific journals published worldwide that document why at least 1.1 million workers die, 250 million workers are disabled, 160 million workers develop occupational disease, and 12 million “youth” workers are injured annually at a cost of 4% of the world’s GNP[1].
     Thirty years ago, the United States government under the pressure of lawsuits brought by the AFL-CIO reluctantly set a responsive standard for asbestos. Other countries quickly followed with their own restrictions, including bans. For some, even an enforced ban was and is too late. In Australia, for example, where a ban is planned but not yet in place, there have been about 7000 cases of mesothelioma, just one of the diseases associated with asbestos exposure, an incurable cancer almost always attributable to asbestos exposure, from 1945 to the present time. The toll is expected to reach 18,000 by 2020[2].
     The risk is not among civilian workers alone. Last month, GEE! received an e-mail from a 27 year old American sailor recently discharged from an aircraft carrier. “I worked in the boiler room,” he wrote, “…uncovered old asbestos insulation…repacked hundreds of valves with asbestos-based packing…replaced hundreds flextallic gaskets that were asbestos-based.” [3].
     Last year, we wrote about an unsuccessful effort by American civilian maintenance workers in US Army facilities in South Korea. They asked the Army to enforce its own rules on asbestos control to protect workers and families of servicemen who maintain and inhabit government facilities contaminated with asbestos. [See archives]
     Thirty years ago, the case could be made that governments in our global society were unaware of the nature and extent of the asbestos hazard. Not today. This explains the attitude of the world’s free labor movement toward any action or even idea that would shift the burden of moral responsibility from the employer, who is often the government, to the worker, including the use of tests for genetic susceptibility to mesothelioma and the other causes of 160 million annual cases of occupational disease. [See Genetic Profiles in this issue and the archive of GEE!]
     Rory O’Neill, editor of Hazards, reports that: “Australia's unions say employers should 'be prohibited from requiring, requesting, collecting or disclosing information derived from genetic testing of current or potential employees.' In a submission to an official commission of enquiry, union federation ACTU says: 'Although sometimes justified in terms of protecting workers' health and safety at work, the ACTU submits that this is an inversion of the fundamental principles; employers are responsible for providing employees with a safe and healthy workplace, while work-related illnesses and injuries are caused by hazards in the workplace, not by employees' genetic make-up.' It adds that 'the focus in workplace health and safety needs to be on hazard removal, not on a mathematical calculation of risk based on genetic testing.' “[4].
     Asbestos is but one of hundreds of toxic agents in the work environment. April 28th is still an important day.

^{[1] Takala, J 1999 in Schulte, PA Approaches to Sharing Occupational Safety and Health Information on a Global Scale. AJIndMed 41,3:210-216 March 2002.}

^{[2] Leigh, J et al. Malignant Mesothelioma in Australia, 1945-2000. AJIndMed 41,3:188-201 March 2002}

^{[3] GEE! editorial policy protects the privacy of reader communications to our editors.}

What Is "Human Ecology"?
    A recent e-mail[1] to GEE!  expresses a common confusion. “I looked at some journals with the title “Human Ecology” and didn’t find a single article from a occupational or environmental health practitioner or scientist. Why does your publication have a section with that title?”
     The reader is correct. Occupational and environmental health [even public health] specialists don’t normally publish in journals of Human Ecology, or belong to the professional societies that publish them. This is an unfortunate expression of their separation from those who identify themselves professionally as human ecologists, who are usually found in academic departments of sociology, anthropology, geography, and what was once called home economics.
     An answer to the second part of the reader’s question begins by noting that public health leaders, such as John Last,[2] in his text on disease causation, writes: “Ecology is concerned with the healthy interaction of living creatures in a closed system. Human ecology includes humans in this system. Humans interact with each other as well as with other living creatures and those interactions can have important effects on the health of all partners in the complex closed ecosystem of our planet.”
     While some may question Last’s belief that the system is closed, and he doesn’t mention the inorganic environment, he is nevertheless taking direction from a long tradition: from the presocratic philosophers of ancient Greece to the present time. The modern tradition of ecology begins with Charles Darwin, one of whose interpreters, Ernst Haeckel, first used the term in 1870: “Ecology is the study of all those complex interrelations referred to by Darwin as the conditions of the struggle for existence.”[3]
     Darwin set us on a path that helps us to foster evolving ecological habits of thought that suggest models of causation that are fruitful. They explicitly incorporate the systems of social and moral values that shape the way in which we select, organize, and interpret the data needed in research or professional practice.
     The recognition of the need to consciously recognize an ecological model of causation in occupational and environmental health was recognized more than two decades ago when the Ergonomics Research Society debated calling itself “The Society for Human Ecology.” There is indeed a current professional organization with that name, but they have little if any interest in ergonomics or its basic science: biomechanics. A quarter century ago, Erwin Tichauer published his classic The Biomechanical Basis of Ergonomics, in which he modeled ergonomics within the work environment as a system of “ecologic stress vectors,” one of which is a set of “sociotactic” stresses.[4] The mainstream of broad ecological thinking supported this insight.
     C. Judson Herrick , a generation ago, looking back at the lifetimes of research in neurophysiology from an ecological perspective by himself and his colleague George Ellett Coghill, perceived that “a practicable biomechanics must include the biosocial and psychosocial factors or it fails utterly to meet the requirements of our times.”[5] He didn’t use the term “human ecology” to describe this perspective in biomechanics, albeit this application of the concept appears to have been in his mind. He did use it to describe the reorganization of the Rockefeller Foundation in 1951, which previously supported a narrow program of eugenics, “on the broad basis of human ecology.”[6]. In fact, he invented another term that has become fashionable in a closely associated, but somewhat narrower direction: “sociobiology”, by which he meant “the search for the biological origins and nature of human patterns of social organization.”[7]  
     Herrick’s perceptions of the need for broad models of thinking should not be surprising. Nearly a half century earlier in the same university community, The University of Chicago, George Herbert Mead, following Henri Bergson of the College de France, integrated cultural [moral and social] and biological theories that lay the basis for an ecological model of causation. Mead observed that even Spencer, a pioneer in the development of evolutionary ethics, “misinterpreted evolution as a process of bare adaptation. If, as Bergson insists, even biologic evolution is creative, then beyond doubt this is the case in social evolution. We fashion hypotheses and test them and intentionally reconstruct the institutions within which we live.”[8]
     “The society in which we belong,” Mead observed, “represents an organized set of responses to certain situations in which the individual is involved, and that in so far as the individual can take those organized responses over into his own nature, and call them out by means of the symbol in the social response, he has a mind in which mental processes can go on, a mind whose inner structure he has taken from the community to which he belongs.”[9] Earlier in the same work Mead noted, “problems which come from within the community itself can be definitely controlled by the community. It is this control of its own evolution which is the goal of the development of human society.”[10]
     These views run counter to other intellectual traditions, e.g., that of Rene Descartes: the picture of a bifurcated world of mechanical bodies and thinking minds, basically different and functioning independently, each according to its own laws, albeit harmonized by an “unmoved mover”.
     The ecological perspective was not rare in Tichauer’s community, even though it was a community within the caste of workers and their attendant professions. The community included the late Irving J. Selikoff, an internationally renowned leader in occupational and environmental medicine. Selikoff addressed what he called the “total burden of risk,” an interdisciplinary cultural and biological approach to occupational risk management that, in his words, “really began with Darwin”.[11]
     At least one of the links integrating cultural and biological causation in this perspective has had strong support among sociologists who have an human ecological perspective. Edward Shils, chronicling the sociological tradition in human ecology at Chicago, observed (interestingly, on the value systems in the division of labor) that “even in the ecological and biological sphere, beliefs about what is right and proper and what is wrong and improper are pervasive, and the physical and biological events are hedged about, controlled, and even instigated in part by these beliefs.”[12]
     Outside their professional community, but within the caste, the views of Tichauer, Selikoff, and others often have not prevailed. A narrower tradition of social values persists in the legal system, for example where claims for wage replacement and medical care for occupational disease are often rejected because of reliance on arbitrary environmental threshold limit values set for a single agent associated with a single disease, excluding multiple agents or causal factors and effects such as depression, chronic fatigue, anxiety, attention deficit, concentration and memory problems as well as numerous physical signs and symptoms for which conventional medicine has little or no answer. It is this narrow tradition that defines, ecologically, the caste of workers and associated professionals.