Compass Minerals International, Inc. to Expand Its Magnesium Chloride Capacity.

OVERLAND PARK, Kan. -- The board of directors of Compass Minerals International, Inc. (NYSE: CMP) has approved plans to expand the company's magnesium chloride production facility in Ogden, Utah, and to install a new mill at the company's Goderich, Ontario, rock salt mine. The plans call for Compass to increase its capital investments by $5 million in 2005 and $14 million in 2006.

"The expansion of our magnesium chloride plant will allow us to take advantage of what we believe are increasingly favorable market conditions in the industry," remarked Michael E. Ducey, president and chief executive officer of Compass Minerals International. "Both projects provide opportunities to reduce production costs in the short term and provide the flexibility to accommodate growth in the long term."

Compass will invest $12 million over the next two years to expand its magnesium chloride evaporation ponds at the Great Salt Lake, upgrade its production facility and add rail infrastructure. The investment is expected to increase the company's capacity to produce liquid magnesium chloride by 70 percent and to double its capacity to produce crystallized magnesium chloride by midyear 2006. In liquid form, magnesium chloride is used for highway deicing and for dust control in rural locations and on construction sites. Crystallized magnesium chloride is used as a premium consumer deicer and in selected industrial applications. Compass Minerals is the leading producer in North America and generated approximately $20 million in revenues from magnesium chloride in 2004.

The remaining funds approved by the board will be invested over the next two years in a high-capacity mill at Compass's Goderich, Ontario, rock salt mine. Milling is the process whereby rock salt is crushed to its customary size and impurities are removed. The new, state-of-the-art equipment is expected to reduce the cost of production, maintenance and energy at the mine and will allow the facility greater flexibility to manage production processes. It is expected to be operational by mid-year 2006.

About Compass Minerals International

Based in the Kansas City metropolitan area, Compass is the second-leading salt producer in North America and the largest in the United Kingdom. The company operates nine production facilities, including the largest rock salt mine in the world in Goderich, Ontario. The company's product lines include salt for highway deicing, consumer deicing, water conditioning, consumer and industrial food preparation, agriculture and industrial applications. In addition, Compass is North America's leading producer of sulfate of potash, which is used in the production of specialty fertilizers for high-value crops and turf.

This press release may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are based on the Company's current expectations and involve risks and uncertainties that could cause the Company's actual results to differ materially. The differences could be caused by a number of factors including those factors identified in Compass Minerals International's annual report on form 10-K filed with the Securities and Exchange Commission on March 16, 2005. The Company will not update any forward-looking statements made in this press release to reflect future events or developments.