EXHIBIT 99.1 FORM OF CHANGE IN CONTROL AGREEMENT CHANGE IN CONTROL AGREEMENT This Change in Control Agreement (this "Agreement"), dated as of June 8, 2005, is made by and between OM Group, Inc., a Delaware corporation (the "Company"), and...Change in Control Agreement • June 14th, 2005 • Om Group Inc • Secondary smelting & refining of nonferrous metals • Ohio
