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testing requirements of the CPSC or the Organization for Economic Cooperation and Development. Each of the protocols included stipulations for adhering to good laboratory practices.
The following results were reported. Oral toxicity in rats was tested with 84 chemicals and mixtures. Each possessed an LD50 of >5 g/kg. According to CPSC criteria, these materials are negative and unlikely to pose an acute hazard to humans by ingestion. Ocular irritation tests in rabbits were conducted with 83 chemicals or mixtures; 55 produced no ocular irritation. According to Tardiff [1997], the 28 materials that tested positive consisted of powders, liquids, and pastes. They produced a range of treatment-related effects, including iridal and/or corneal involvement and slight to moderate conjunctival irritation (which cleared within 24 to 72 hr of the test material administration). According to the author, these substances are unlikely to lead to positive results in humans exposed to CCP because the test results indicated only mild and transitory effects with liquids, and end users would not be exposed to the liquids.
Primary skin irritation tests in the guinea pigs were conducted with 86 chemicals or mixtures. Each produced a skin irritation score of less than 5. Tardiff [1997] states that based on CPSC criteria and the primary irritation scoring data, these materials are negative and are unlikely to cause primary skin irritation in humans exposed to CCP. Acute dermal toxicity tests in rabbits were conducted with 18 chemicals or mixtures. Each possessed an LD50 >2 g/kg. On the basis of CPSC criteria, these materials are negative for acute dermal toxicity. Skin sensitization tests in guinea pigs were performed with 95 chemicals or mixtures. Eighty-seven were negative. Of the eight positive tests, treatment-related results ranged from very faint to faint erythema reactions that cleared within 24 hr of the test material administration. Six materials were tested as liquids—which does not represent normal usage of CCP. Therefore, Tardiff [1997] concludes that these reactions would not occur in humans. The other two positive substances were tested as powders. Because the exposure is expected to be limited to "minute" quantities produced as CCP is cut, shredded, or torn, the doses encountered were considered insufficient by the authors to cause sensitization.
Acute inhalation toxicity testing in rats was conducted with 44 chemical substances or mixtures. Forty-three were negative according to CPSC criteria. The only positive result came from a liquid mixture with an LC50 between 2 and 200 mg/L. Treatment-related effects included failure to gain expected body weight, respiratory distress, increased secretory responses, other changes in hair coat, and death. Since exposure conditions with normal use of CCP would not be in liquid form, Graves and Tardiff [1999] concluded that the test material was unlikely to be an acute hazard to humans by inhalation.
All 22 chemicals or mixtures tested for genotoxicity were negative for point mutations and did not increase chromosomal aberrations. These toxicity tests demonstrate that the tested CCP constituents are not mutagenic.
4.3.3 Summary
After examining the toxicological animal studies submitted to the NIOSH docket, NIOSH concludes that with a few exceptions, CCP constituents are not acutely toxic by the oral, dermal, or inhalation route. A number of CCP
