PORTAGE, Wis. (AP) -- A project that will reduce air pollution at one of the state's largest coal-fired power plants is under way.

Wisconsin Power & Light says the $627 million project at the Columbia Energy Center near Portage will result in hundreds of construction jobs in Columbia County through 2014, when the work is expected to be done.

WP&L spokesman Steve Schultz says during the peak of construction, there will be about 600 workers on site. The Journal Sentinel says the Columbia plant is the state's largest source of sulfur dioxide, which can contribute to asthma and respiratory problems. It's also the state's largest source of mercury emissions.

In addition to WP&L, the other owners of the plant are Wisconsin Public Service Corp., of Green Bay, and Madison Gas & Electric Co.