These standards will reduce emissions of harmful pollutants including mercury, lead, cadmium, nitrogen dioxide and particle pollution.

Environmentalists say they are concerned about possible toxic chemicals at the Bronx site, including mercury, barium and lead.

These standards identify levels for pollutants, including mercury, that must be met in order to protect human health, fish, and wildlife.

No person may discharge pollutants, including mercury, into waters unless the person has a permit.

Their equipment and materials, including silver, copper and mercury, were also expensive.

The plant annually burns 63,000 tons of hazardous waste, including lead, mercury and hundreds of other toxic chemicals.