How does the EPA categorize carcinogens?

The EPA categorizes carcinogens specifically based on their potential to cause cancer. This classification is grounded in extensive research that evaluates the relationship between exposure to certain substances and the likelihood of developing cancerous conditions. The agency relies on scientific studies and data assessments to determine whether a substance poses a risk, which is critical in guiding public health decisions and regulatory requirements.

In contrast, the other options imply categorizations based on different criteria. For instance, physical harm encompasses a broader range of injuries and health impacts besides cancer, while environmental effects focus on how substances interact with ecosystems rather than their influence on human health. Volatility relates to how substances behave under various storage conditions but does not correlate directly with carcinogenicity. Thus, the focus on the potential to cause cancer is what defines the EPA's categorization of carcinogens.