Hazard class: Germ cell mutagenicity (Category 2). Suspected of causing genetic defects (H341). Obtain special instructions before use (P201). Do not handle until all safety precautions have been read and understood (P202). Use personal protective equipment as required (P281). Hazard class: Carcinogenicity (Category 1B). May cause cancer (H350). Phenolphthalein is categorized as "Reasonably anticipated to be a human carcinogen" by the National Toxicology Program (first listed in 2000). Hazard class: Reproductive toxicity (Category 2). Suspected of damaging fertility or the unborn child (H361).