these substances do not necessarily have to be treated as select carcinogens. However, because of the chemical similarity of these compounds to chloromethyl methyl ether, these substances may have comparable carcinogenicity, and it is prudent to regard them as select carcinogens requiring the special handling procedures outlined in section 6.D.
Whether a suspected carcinogenic chemical is treated as a PHS in the context of a specific laboratory use is affected by the scale and circumstances associated with the intended experiment. Trained laboratory personnel must decide whether the amount and frequency of use, as well as other circumstances, require additional precautions beyond the basic prudent practices of section 6.C. For example, the large-scale or recurring use of such a chemical might suggest that the special precautions of section 6.D be followed to control exposure, whereas adequate protection from a single use of a small amount of such a substance may be obtained through the use of the basic procedures in section 6.C.
When evaluating the carcinogenic potential of chemicals, note that exposure to certain combinations of compounds (not necessarily simultaneously) causes cancer even at exposure levels where neither of the individual compounds would have been carcinogenic. 1,8,9-Trihydroxyanthracene and certain phorbol esters are examples of tumor promoters that are not carcinogenic themselves but dramatically amplify the carcinogenicity of other compounds. Understand that the response of an organism to a toxicant typically increases with the dose given, but the relationship is not always a linear one. Some carcinogenic alkylating agents exhibit a dose threshold above which the tendency to cause mutations increases markedly. At lower doses, natural protective systems prevent genetic damage, but when the capacity of these systems is overwhelmed, the organism becomes much more sensitive to the toxicant. However, individuals have differences in the levels of protection against genetic damage as well as in other defense systems. These differences are determined in part by genetic factors and in part by the aggregate exposure of the individual to all chemicals within and outside the laboratory.
4.C.3.7 Control Banding
Control banding is a qualitative risk assessment and management approach to assist in determining the appropriate handling of materials without occupational exposure limits (OELs) and to minimize the exposure of personnel to hazardous material.2 It is not intended to be a replacement for OELs but as an additional tool. The system uses a range of exposure and hazard “bands” that, when mapped for a given material and application, help the user determine the appropriate safety controls that should be in place. The approach is built on two major premises: (1) there are a limited number of control approaches and (2) that many problems have been encountered and solved before. Control banding uses the solutions that experts have developed previously to control occupational chemical exposures and applies those solutions to other tasks with similar exposure concerns.
By considering the physical and chemical characteristics and hazards posed by the material (e.g., toxicity), the quantity used, the intended use or application, and the mode of exposure (e.g., inhalation), a graduated scale of controls can be applied, from general ventilation requirements to requiring containment of the material to recommending that the user seek expert advice. Because this approach is expected to provide simplified guidance for assessing hazards and applying controls, it is anticipated that control banding will have utility for small- and medium-size nonchemical businesses; however, larger companies may also find it useful for prioritizing chemical hazards and hazard communication.
Note that a number of control banding models exist, each with its own level of complexity and applicability to a variety of scenarios. Within the United States, questions about the utility of control banding for workplaces initiated a review by NIOSH on the critical issues and potential applications of the system. The resulting report, Qualitative Risk Characterization and Management of Occupational Hazards: Control Banding (CB) (HHS/CDC/NIOSH, 2009b), can be found on the NIOSH Web site. It provides an overview of the major concepts and methodologies and presents a critical analysis of control banding.
Control banding is of interest internationally, and variations on the methodology can be found in many countries. More information about control banding can be found by consulting these Web sites and articles.
• (UK Health and Safety Executive) Control of Substances Hazardous to Health Regulations, www.coshh-essentials.org.uk/
• ILO Programme on Safety and Health at Work and the Environment (SafeWork), www.ilo.org/
• NIOSH, www.cdc.gov/niosh/
• “Training Health and Safety Committees to Use Control Banding: Lessons Learned and Opportunities for the United States” (Bracker et al., 2009)
• “Evaluation of COSHH Essentials: Methylene Chloride, Isopropanol, and Acetone Exposures in a Small Printing Plant” (Lee et al., 2009)
2For information on how OELs are determined, see Alaimo (2001).