The U.S. Environmental Protection Agency announced this month new emission limits for cement kilns, with the hope of cutting annual emissions of mercury and hydrocarbons. According to an EPA statement, “These limits will help protect public health from mercury and total hydrocarbon emissions from portland cement kilns, through amendments to an air toxics standard issued on December 8.”

The amendments set mercury and hydrocarbon levels for all cement kilns built after December 2, 2005, and will reduce annual mercury emissions by about one ton and annual hydrocarbon emissions by about 1,100 tons, according to EPA. Kilns built before that time must meet work practice requirements, such as removing cement kiln dust when it no longer can be recycled and operating kilns properly to ensure complete combustion.

In addition, the amendments prohibit all cement kilns from using fly ash from utility boilers equipped with certain utility mercury emission controls (such as activated carbon injection), unless the cement kiln can demonstrate that use of that fly ash will not increase mercury emissions.

While EPA proposed setting limits for hydrogen chloride for cement kilns, the agency determined they were unnecessary, since such emissions at cement kilns are better than levels considered protective of public health.

In separate action, EPA announced that it will reconsider the mercury and hydrocarbon emissions for new kilns and take immediate steps to obtain additional information about mercury reductions achieved at kilns equipped with wet scrubbers. The information will include results of field testing at kilns equipped with these scrubbers, and EPA says it will make this information available for public review and comment.

The agency estimates costs for meeting the both new emission standards at $26 million to $28 million a year five years after the amendments are published in the Federal Register.