What is the maximum contaminant level goal (MCLG) for substances that are expected carcinogens?

The maximum contaminant level goal (MCLG) for substances classified as expected carcinogens is set at zero. This is because MCLGs are health-based standards developed by the Environmental Protection Agency (EPA) for drinking water pollutants. The rationale for setting the MCLG for expected carcinogens at zero is based on the principle of precaution in public health. Since these substances are known or suspected to cause cancer in humans, the goal is to eliminate any associated risk of exposure.

In the case of carcinogens, even the smallest detectable amount can potentially pose a risk to human health. Therefore, the regulatory goal is to strive for a level of exposure that is as low as possible, ideally zero, to protect public health effectively.