 Between 2010 and 2012, the Centralia Power Plant has been offline for an average of 4 months of each year.In March 2009, a proposed agreement between TransAlta and the Washington State Department of Ecology was announced, regarding a significant step forward in improving air quality in Washington.Key to the agreement is TransAlta's willingness to voluntarily reduce mercury emissions by at least 50 percent by 2012 to address air quality concerns in the region.