Which of the following are known carcinogens?

The correct response identifies phenolics as known carcinogens. Phenolics are a class of compounds that can pose significant health risks, especially in the context of long-term exposure. They are associated with various health issues, including cancer, due to their ability to cause cellular damage and influence biological pathways that can lead to cancerous growths.

While alcohols can have health implications with excessive consumption, they are not classified as direct carcinogens. Formaldehyde is also known to be a carcinogen and is used in various industrial and laboratory settings, which suggests that the question may involve nuances regarding the specific contexts of exposure. Chlorine compounds, particularly in certain concentrations, have been linked to respiratory issues but are not classified as direct carcinogens in the same way as phenolics. Understanding the specific classifications and mechanisms through which these substances operate is crucial for recognizing health risks, particularly in environments such as salons or laboratories where such chemicals may be used.