Three subsidiaries of the Potash Corporation of Saskatchewan (PCS), the world's largest fertilizer producer, have agreed to take action to reduce harmful air emissions at eight U.S. production plants.

In a settlement announced last week by the U.S. Environmental Protection Agency (EPA) and Department of Justice, PCS Nitrogen Fertilizer, AA Sulfuric Inc. and White Springs Agricultural Chemicals Inc. will install, upgrade and operate state-of-the-art pollution reduction measures, as well as install emissions monitors, at eight sulfuric acid plants in Geismar, La. (one plant), White Springs, Fla. (four plants) and Aurora, N.C. (three plants).

This settlement resolves claims that the three businesses violated the Clean Air Act when they modified facilities in ways that released excess sulfur dioxide into surrounding communities.

The three subsidiaries will spend an estimated $50 million on the agreed measures and will also pay a civil penalty of $1.3 million.

An additional component of the settlement is a "supplemental environmental project" designed to protect the community around the PCS Nitrogen nitric acid plant in Geismar, Louisiana. PCS Nitrogen is required to install and operate equipment to reduce emissions of nitrogen oxide and ammonia at a cost of between $2.5 million and $4 million.

The EPA said that this project is part of its commitment to advancing environmental justice by reducing the disproportionate environmental impacts on communities near industrial facilities. In this case, the new equipment will reduce the release of fine particulates that can aggravate respiratory disease.