Which agency usually sets the maximum contaminant levels (MCLs) for drinking water?

The Environmental Protection Agency (EPA) is responsible for establishing maximum contaminant levels (MCLs) for drinking water in the United States. This regulation ensures that water supplies are safe for human consumption by setting limits on the concentration of specific contaminants that can be present, thereby protecting public health. The MCLs are established based on rigorous scientific research that assesses health risks associated with various contaminants.

The other agencies listed have different areas of focus. OSHA is primarily concerned with occupational safety and health, ensuring safe working conditions for employees. The CDC focuses on public health and disease prevention but does not set drinking water standards. The FDA regulates food safety and some aspects of bottled water but does not set MCLs for public drinking water supplies. Thus, the EPA is the logical and correct choice for this question.