Federal regulators have agreed to set standards for mercury emissions from cement plants under a legal settlement with activists and nine states, including New York.

The deal comes after a decade of wrangling over air pollution from 106 cement plants around the nation. They annually generate nearly 23,000 pounds of airborne mercury, according to Earthjustice, an environmental law firm.

EPA actually issued mercury regulations for cement plants three years ago, but they applied only to kilns built after December 2005. Kilns built earlier -- the vast majority of those now operating -- were exempt.

A  study by Lafarge Cement of Ravena released earlier this month to the NYS Department of Environmental Conservation showed it was a major mercury source.  The report found more than half the estimated 146 pounds of mercury emitted by the Albany County plant each year comes from local limestone used to produce cement.