The U.S. National Toxicology Program (NTP) conducted 2-year bioassays of commercial grade toluene diisocyanate (TDI) (80% 2,4-TDI and 20% 2,6-TDI) and 2,4-toluene diamine (TDA) and concluded that both were carcinogenic in rodents. In the TDI study, there was an unproven but likely formation of TDA either because of flawed test-substance handling and storage conditions and/or the atypical exposure conditions employed. Although the carcinogenic responses in both studies were qualitatively similar, several statistical analyses were performed to substantiate this possibility more rigorously. Seven different statistical approaches combine to yield a robust and consistent conclusion that, if only a small fraction (approximately 5%) of the dose of TDI were hydrolyzed to TDA in the TDI study, then that would be sufficient to explain the observed carcinogenic responses in the TDI study.

美国国家毒理学计划 (NTP) 对商业级甲苯二异氰酸酯 (TDI)（80% 2,4-TDI 和 20% 2,6-TDI）和 2,4-甲苯二胺 (TDA) 进行了为期 2 年的生物测定，并得出结论两者都对啮齿动物具有致癌性。在 TDI 研究中，由于测试物质处理和储存条件有缺陷和/或采用的非典型暴露条件，存在未经证实但可能形成 TDA。尽管两项研究中的致癌反应在性质上相似，但进行了多项统计分析以更严格地证实这种可能性。七种不同的统计方法相结合，得出了一个可靠且一致的结论，即，如果在 TDI 研究中只有一小部分（约 5%）的 TDI 剂量被水解为 TDA，