Washington, D.C. ? The Obama administration proposed Friday reducing mercury emissions by more than 50 percent and cutting hundreds of tons of cancer-causing toxic metals emitted by industrial boilers, process heaters and solid waste incinerators by December.

The proposal would require large boilers and all incinerators to meet emission limits for mercury — a toxin that can damage the brains and nervous systems of unborn babies and young children — and other pollutants.

Facilities with boilers are also required to conduct energy audits to look for cost-effective ways to reduce fuel use and emissions. Smaller facilities, such as schools with smaller boilers, would not be subjected to these requirements, but they are required to perform tune-ups every two years.

The EPA said that when fully implemented, the plan would yield at least $18 billion worth of health benefits annually and prevent up to 5,200 premature deaths and about 36,000 asthma attacks a year. The EPA estimates it would cost $3.6 billion to install and maintain pollution controls required under these rules.