Also

* Energy explorer Kerr-McGee Corp. said it was buying Denver-based Westport Resources Corp. for about $2.5 billion in stock in a deal that would create one of the nation’s biggest independent oil and gas producers.

* Merck & Co. said it planned to grant a license to a South African company to make and sell a generic version of efavirenz, a key anti-retroviral AIDS drug.

* Footstar Inc., an athletic-shoe retailer that filed for bankruptcy protection last month, won court approval to auction its 355 Footaction stores April 16 to pay some of the company’s debt.

* Tyson Foods Inc., Cargill Inc. and other U.S. meatpackers will spend as much as $149.1 million a year to comply with emergency regulations imposed by the government to protect the beef supply from mad cow disease, the Agriculture Department said.