Carbon Black: Kuempel et al. Respond

Environmental Health Perspectives • volume 119 | number 8 | August 2011 A 333 Ward et al. (2010) recommended that “the relation ship between occupational exposure to carbon black and validated bio markers of oxidative stress should be examined.” Despite the appeal of biomarkers of oxidative stress in pinpointing inflammatory changes associated with malignant and non malignant illnesses, such markers are non specific, not well validated, and appear not “ready for prime time,” as noted in a recent symposium on nano toxicology (Fischman et al. 2011). A meta-analysis of all three major carbon black cohorts (United States, United Kingdom, and Germany) to assess risk of heart disease is also under way. In a recent position paper, Brook et al. (2004) noted that particle exposure may play a role in the develop ment of heart disease. Ward et al. (2010) suggested evaluating carbon black particle size and surface area. However, the physi cal and chemical properties of untreated manufactured carbon blacks are distinctly different from ubiquitous carbon core particulates in both occupational and ambient atmospheres (Kuhlbusch and Fissan 2006). Approximately 90% of manufactured carbon black is used for tire and automotive rubber products. In products, such as toners, plastics, and surface coatings, carbon black is matrix-bound, and not an exposure risk to end-users. Care should be taken when applying quantitative models that claim to address the particle size and surface area topics (Tomenson and Morfeld 2010). The authors serve as scientific advisors to the International Carbon Black Association (ICBA), a scientific, non-profit corporation originally founded in 1977, with the purpose of sponsoring, conducting, and participating in investigations, research, and analyses relating to the health, safety, and environmental aspects of the production and use of carbon black. This manuscript was neither influenced by the ICBA nor by any company funding the ICBA, nor does it present any view or opinion of the ICBA or of the companies. H.M. is president of Muranko and Associates, a consulting company that provides industrial hygiene and safety services and serves as expert witness in industrial safety cases.