PHOENIX (April 22)—Manuel J. Iraola will retire as president and CEO of Phelps Dodge Corp.'s specialty chemicals unit, Columbian Chemicals Co., effective June 30 and be replaced as president by James P. Berresse. Iraola has been with Columbian Chemicals since 1984, when he served as senior vice president and chief financial officer. He became president of Phelps Dodge International Corp. in 1992 and three years later became president of Phelps Dodge Industries and CEO of Columbian Chemicals. When Jack Walsh retired as the carbon black maker's top executive last summer, Iraola assumed the firm's presidency in addition to his other responsibilities. Berresse, who joined Phelps Dodge in 1993 as director of business analysis and planning for the company's mining and metals division, had most recently been executive vice president of the firm's carbon black operations.