Kerr-McGee Accepts 46.7 Million Shares in Dutch Auction

Kerr-McGee Corp. (NYSE: KMG) has accepted for payment an aggregate of 46,727,763 shares of its common stock at a purchase price of $85 per share under its modified "Dutch Auction" self tender offer. These shares represent approximately 29% of the shares outstanding as of March 31, 2005. Kerr-McGee has been informed by the depositary for the tender offer that the final proration factor for the tender offer is approximately 33.64%.

Based on the final count by the depositary for the tender offer, approximately 138,896,136 shares were properly tendered and not withdrawn at a price of $85 per share. Kerr-McGee has exercised its right to increase the number of shares purchased pursuant to the tender offer by 3,227,763 shares, which are included in the 46,727,763 shares referred to above, in accordance with applicable securities laws without extending the tender offer. The offer to purchase shares expired on Wednesday, May 18, 2005, at midnight EDT.

Payment for the shares accepted for purchase and return of all other shares tendered and not accepted for purchase will be carried out promptly by the depositary. With completion of the tender offer, Kerr-McGee now has approximately 115.1 million shares of common stock outstanding.

For questions and information about the tender offer, please contact the information agent, Georgeson Shareholder Communications Inc., toll free at 1-877-278-6310.