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 some conditions, resulted in symptoms of irritation of the skin and of the mucosal membranes of the eyes and upper respiratory tract.

This conclusion is based primarily on interpretation of the evidence from the epidemiologic studies. Although the magnitude of the effects observed in these studies was only weak to moderate, these studies were reasonably consistent in reporting an association and evidence of an exposure-response relationship between CCP exposure and irritative symptoms of the eyes, skin, and upper respiratory tract. The plausibility of the epidemiologic evidence is supported by the presence of known irritants in some types of CCP, toxicologic studies that demonstrate mild irritation in laboratory animals exposed to CCP, and the evidence for respiratory and skin irritation in some of the experimental laboratory studies in humans. Some of the epidemiologic studies may have been biased, particularly by overreporting from study subjects who were already concerned about the potential effects of CCP exposure (i.e., recall bias). However, it is unlikely that recall bias could explain the associations observed between CCP exposure and irritative symptoms of the eyes, skin, and upper respiratory tract in the indoor air quality studies, since these studies were not conducted in an atmosphere of concern regarding the health effects of CCP. Exposure to CCP or its components may rarely cause allergic contact dermatitis.

This conclusion is based on published case reports of allergic contact sensitization and results reported in several industry-sponsored RIPT studies. Cases of allergic contact dermatitis were reported only in RIPT studies from the 1970s that were submitted to the 1987 NIOSH docket; no cases were reported in the studies submitted to the 1997 docket. This fact may indicate that the CCP component responsible for the allergic contact dermatitis observed in the early studies was removed from the more recent formulations of CCP. Systemic reactions have occurred in a few persons exposed to CCP.

This conclusion is based on the finding that three such cases have been reported in the peer-reviewed medical literature. No cases have been reported in the last 7 years, and thus there is no evidence that current exposures to CCP present a risk for this health outcome. Data are insufficient to evaluate claims of other adverse health effects (such as neurologic effects and reports of MCS) that have been suggested in some of the clinical reports submitted to the NIOSH docket.

In conclusion, although the weight of the evidence indicates that exposure to CCP in the past has resulted in adverse health effects, it is uncertain whether current formulations of CCP represent a significant risk to exposed workers. Only a few cases of systemic reactions and allergic contact dermatitis have been reported in the United States or in Europe, which suggests that the risk of these serious outcomes is extremely low given the large number of people who have been exposed to CCP over a period of many years. Recently conducted experimental studies in humans (RIPT studies) suggest that the potential for skin irritation from exposure to current formulations of CCP is nonexistent, or at most slight. However, it is unclear how well these experimental studies simulate the exposures and