What was the maximum contaminant level (MCL) for arsenic in drinking water lowered to by the EPA in 2001?

The maximum contaminant level (MCL) for arsenic in drinking water was lowered to 0.01 mg/l (10 ppb) by the EPA in 2001. This change was made to enhance public health protections, as arsenic is recognized as a potent carcinogen and can cause various adverse health effects, including skin cancer and developmental effects, when present in drinking water at elevated levels. The decision to reduce the MCL reflects an ongoing commitment to improving water quality and safeguarding population health by ensuring that arsenic levels are kept as low as feasible. Lowering the MCL aimed to reduce the risk of exposure and disease, supporting the broader objectives of the Safe Drinking Water Act to protect public health through the regulation of contaminants in water supplies.